EX-10.15
                              Lease Agreement wiith Apple Computer, Inc.

                                      LEASE
   
THIS LEASE,  executed in duplicate  at  Cupertino,  California,  this 6th day of
January,  1978,  by and between JOHN A. SOBRATO and SUSAN R.  SOBRATO,  as to an
undivided 45%  interest,  and CARL E. BERG and MARY ANN BERG, as to an undivided
45% interest, and ANN S. RUSSO as to a 10% interest, herein collectively Lessor,
20700  Valley  Green  Drive,  Cupertino,   California,  and  TYMSHARE,  INC.,  a
California corporation, 20705 Valley Green Drive, Cupertino,  California, herein
Lessee. For convenience, references herein to Lessor and Lessee shall be without
regard to number or gender.
    

IN CONSIDERATION of the mutual promises exchanged, it is agreed as follows:

1. Premises Leased: Lessor leases to Lessee and Lessee takes from Lessor, on the
terms and  conditions  hereinafter  set forth,  that  certain  two-story  office
building commonly known as 20705 Valley Green Drive, Cupertino,  California (the
"existing  facility"  premises),  together with an additional  two-story  office
building to be constructed at Lessor's  expense in accordance with the plans and
specifications  approved by Lessee,  comprised of an approximate  sixty thousand
(60,000)  square foot  building  (the  "additional  facility"  premises) on real
property  adjacent to the existing  facility  premises.  The  existing  facility
premises and additional facility premises are sometimes hereinafter collectively
referred  to as the  "premises".  The real  property  covered  by this  lease is
located in the City of Cupertino, County of Santa Clara, State of California and
more  particularly  described  on Exhibit A,  attached  hereto and  incorporated
herein by reference.

2. Term of Lease:

(a) Initial Term: The initial term of the Lease shall be for fifteen (15) years,
commencing  January 1, 1978 and ending  December 31, 1992,  provided,  if Lessor
cannot deliver possession of the additional  facility on or before July 1, 1978,
Lessee may, at its option  terminate  this Lease except for delays caused by (i)
war or  insurrection;  (ii)  strike,  lockout  or  other  labor  dispute;  (iii)
unavailability  of materials or  equipment;  (iv) delays  caused by acts of God,
local or state  governing  bodies,  or inclement  weather beyond the control and
without the  negligence of Lessor.  In the event Lessee  exercises his option to
terminate  this  Lease,  upon such  termination,  the terms  and  conditions  of
Lessee'.  occupancy of the existing facility shall be covered by the Lease dated
October 24, 1974 by and between the parties hereto.

(b) Options to Renew: Lessee shall have the right and option to renew this Lease
for three (3) additional five (5) year terms commencing  automatically as of the
expiration  date of the initial or any extended term,  upon Lessee giving Lessor
written notice of exercise of its option to renew at least 180 days prior to the
expiration of the initial or any extended  term. Any extended term shall be upon
all the terms and  conditions  set forth  herein,  except that the monthly  base
rental  for  such  extended  term  shall  be  adjusted  in  accordance  with the
provisions of Sections 3(c) and 3(d) hereof.

3. Rental Consideration.

(a) Monthly  Base  Rental.  The monthly  base rental for the initial term of the
Lease shall be the sum of Forty-Five  Thousand Three Hundred Seventy-two Dollars
($45,372.00) per month, subject to adjustment at the time of Lessee's possession
of the additional  facility,  based upon Lessor's  actual costs,  as the parties
have agreed  separately,  provided  however  that there shall be an abatement of
monthly base rental in the stem of Twenty-Two  Thousand Eight Hundred Fifty-Five
Dollars  ($22,855.00) during the period of time between commencement of the term
of this  Lease  and the  time  when  Lessee  actually  takes  possession  of the
additional  facility.  Any  partial  month to be prorated on a basis of the date
Lessee actually takes possession of the additional facility. Each installment of
monthly  base rental  shall be payable in advance on the first day of each month
during the term of the Lease  (subject to the  foregoing  relating to  abatement
prior to completion of the additional facility).

(b) Payment of Taxes:  At least ten (10) days prior to delinquency  Lessee shall
pay to Lessor,  or in the event the  premises  are  separately  assessed for tax
purposes,  Lessee shall pay to the public  officers  charged with the collection
thereof, all real and personal property taxes,  assessments and charges that are
now or may hereafter be levied, assessed, charged, or imposed upon the premises,
the improvements, or any of them now or hereafter constructed upon the premises,
commencing  with  taxes and  assessments  levied and  assessed  for the tax year
1977-1978,  prorated as of the date of  possession  of the  additional  facility
premises by Lessee.  Lessor will promptly advise Lessee of all notices,  levies,
and assessments of taxes and other charges respecting the property. Lessee shall
have the right, at its election, to contest in the name of Lessor, or in its own
name, any tax, levy or assessment which Lessee is required to pay hereunder,  in
whole or in part. Lessor shall execute all documents necessary-or appropriate to
effectuate the purposes of this  subparagraph  and to perfect Lessee's rights of
contest.  In the event that taxes are assessed against a parcel or parcels where
the demised  premises  only form a part of such parcel,  Lessee's  liability for
such taxes shall be equitably prorated.

(c) Rental Adjustment.

      (1)  "Adjustment  Base"  shall  be the sum of  Forty-Five  Thousand  Three
      Hundred Seventy-two Dollars ($45,372.00), as may be reduced based upon the
      Lessor's actual cost savings 1n completing the additional facility.

      (2) "Fair rental  value" shall mean the going market rental as of the date
      of any  adjustment  of rent or extension of this  Lease-,  for  equivalent
      space of similar age and  construction by a tenant  proposing to execute a
      Lease  of  five  (5)  years  minimum   term,   and  having  the  financial
      qualifications similar to Lessee's. In determining "fair rental value" the
      parties shall confer in order to reach agreement and in the event they are
      unable to reach agreement,  the matter shall be referred to arbitration by
      one appraiser,  experienced in the evaluation of similar rental properties
      in the County of Santa Clara,  State of  California,  whose  determination
      shall be final for all purposes.

      (3) Any  adjustment  of monthly  base rental  provided for herein shall be
      made in an amount  equal to the lesser of: (i) a sum equal to one  hundred
      percent (1001) of the adjustment  base plus 2.5% of such  adjustment  base
      per year or portion  thereof  during the initial  term of the Lease or any
      extension,  or (ii) a monthly  rental equal to the "fair rental  value" of
      the premises as of the effective date of such  adjustment.  Any adjustment
      in the monthly base rental so determined  shall be the monthly base rental
      for  the  succeeding   period  as  provided  herein.  In  the  event  such
      determination  is made  subsequent  to any date provided for herein as the
      effective date for such adjustment, the adjusted monthly base rental shall
      be  retroactive  to the date  provided  for herein.  In no event shall the
      monthly base rental  during any adjusted  period be lower than the monthly
      base rental during the period immediately preceding such extension.

(d) Adjustment of Base Monthly Rental.  The monthly base rental for the premises
shall be adjusted in  accordance  with  Section 3(c) hereof  effective  June 30,
1985, such adjusted  monthly base rental to be in effect for the remaining seven
and one-half (7 1/2) years of the initial term of this Lease. Thereafter, in the
event Lessee exercises any of its options to renew the monthly base rental shall
adjusted in accordance with Section 3(c) hereof as of the  commencement  date of
any such renewal term.

(e) Taxes:  Should the State of California or any political  subdivision thereof
(including the County of Santa Clara or City of Cupertino) levy or impose a tax,
assessment,  license fee or other charge upon this Lease,  the estate created by
this Lease, or upon the Lessor by reason of its ownership of the fee interest in
the property, or upon the rents or other income of the Lessor from the property,
and such tax, assessment,  license fee or other charge is assessed,  in whole or
in part,  in lieu of property  taxes and  assessments,  the parties shall confer
upon an equitable  allocation of such tax between Lessor and Lessee,  based upon
the  extent to which  Lessor  can  reasonably  establish  that such new tax is a
substitute for real property taxes assessed  against the premises for the fiscal
period next preceding  enactment of the new tax. In the event the parties cannot
agree upon an equitable allocation of such new tax, the issue shall be submitted
to  arbitration  in  accordance  with the  then  current  rules of the  American
Arbitration  Association.  with any  amount  payable  by Lessee and Lessor to be
deemed to be additional rent under the terms of this Lease.

4. Use: The premises may be used by Lessee for any and all lawful purposes,  but
initially  for the  purpose  of  administrative  offices,  data  processing  and
communications  operations.  Lessee  shall  abide by all  laws,  ordinances  and
statutes,  as they now exist or may hereafter be enacted by  legislative  bodies
having jurisdiction thereof,  relating to its use and occupancy of the premises,
provided  that any changes in the laws,  ordinances or statutes of any governing
body thee may be hereafter  enacted shall not be deemed a breach of any covenant
of this lease by Lessee.

5.  Modification  to Premises - Waste:  Lessee  shall not commit or suffer to be
committed  any waste upon the premises,  or any nuisance.  Lessee shall have the
right to construct, alter, modify, or improve any improvements upon the premises
as in its sole  discretion it may deem necessary or appropriate  for its use and
occupancy of the premises, provided that prior to such construction,  alteration
or improvement Lessee shall obtain the written consent of Lessor,  which consent
shall not be  unreasonably  withheld.  Any consent by Lessor to  construction by
Lessee of alterations or  improvements  to the premises may be conditioned  upon
Lessee's  agreement to remove such  alterations or improvement at the expiration
of this Lease and restore the premises to their original  condition,  subject to
reasonable wear and tear based upon the age of the other improvements.

6. Maintenance of Premises: Subject to any construction guarantees or warranties
by Lessor or its  subcontractors,  Lessee  shall at its sole  expense,  keep and
maintain the premises and appurtenances, including but not limited to sidewalks,
parking areas,  electrical  and air  conditioning  systems,  roof (provided that
Lessor  shall  keep and  maintain  the roof for a period  of the first 24 months
after completion of construction, except for damage caused by the negligent acts
of Lessee),  and interior of the premises in good and sanitary order,  condition
and repair. Further, all water, gas, electricity or other public utility service
used  upon or  furnished  to the  premises  during  the term of the lease or any
extension shall be paid for by Lessee.  Lessee shall maintain and replace,  when
necessary,  any shrubbery,  paving, or landscaping,  provided by Lessor upon the
leased premises.  In the event Lessee's premises are only a portion of the site,
then Lessor  shall  maintain  and replace  when  necessary  any such  facilities
located upon the leased  premises and the cost of such  maintenance,  repair and
replacement  shall be equitably  prorated with the annual cost  reimbursable  to
Lessor  within ten (10) days after Lessor  provides  evidence of payment of such
expenses.  Lessee  waives all right to make  repairs at the expense of Lessor as
provided in Section 1942 of the Civil Code of the State of  California.  Lessor
shall,  at its sole expense,  maintain and repair any defects in the  structural
portions of the buildings comprising the leased premises (e.g.,  concrete walls,
footings,  concrete  slab,  roof  structure),  except  for  any  damage  to  the
structural portions caused by the negligent acts of Lessee.

7. Parking Area: Lessee shall have,  without  additional rental, for the use and
benefit of Lessee, its agents,  employees and customers,  the exclusive right to
use 100% of the  parking  area on the  premises  during the  entire  term or any
extension of the Lease for parking,  ingress,  egress of  automobiles  and other
vehicles. Lessee is to pay any parking use fees, taxes or assessment which might
hereafter be imposed by any Municipal, State of Federal authority.

8.  Damage or  Destruction  of the  Premises:  If either  building  in which the
premises are situated  shall be  substantially  damaged or destroyed  during the
term hereof 'or any cause, Lessor shall forthwith repair the same, provided such
repairs can be made within one hundred eighty (180) days by working in the usual
and  ordinary  manner  under the laws and  regulations  of the State,  County or
municipal  authorities,  but such damage or destruction shall in no way annul or
void this  Lease,  except  that  Lessee  shall be  entitled  to a  proportionate
reduction  of rental  while such  repairs  are being  made,  such  proportionate
reduction to be based upon the extent to which the making of such repairs  shall
interfere  with the business  carried on by the Lessee in the premises.  If such
repairs  cannot be made in said manner in one hundred  eighty  (180) days,  this
Lease may be  terminated  by either  party upon giving  notice in writing to the
other party on or before said one hundred  eighty (180) days.  Said  termination
shall be effective  thirty (30) days after any party gives such notice.  Whether
or not such  repairs can be made within one hundred  eighty  (180) days,  Lessee
shall in all events be entitled to an  abatement of rental from the time of such
event and during the time such repairs are being made.

9. Condemnation:  If the premises or any portion of the structure shall be taken
under any right of eminent  domain,  or any transfer in lieu  thereof,  and such
taking  renders the leased  premises  unsuitable  in the  judgment of Lessee for
Lessee's business  operations,  Lessee may cancel this lease effective as of the
time of such taking by giving  notice to Lessor  within thirty (30) days of such
taking.  Lessee  shall be entitled to  reimbursement  for the value of any trade
fixtures, equipment and other property installed by it, moving expenses or other
special damages provable in any condemnation action. Lessor shall be entitled to
claim and have paid to it all other  compensation  awarded for the taking  under
the  power of  eminent  domain,  except  that  upon  termination  of this  Lease
agreement  under the provisions of this  paragraph,  Lessee shall be entitled to
have  compensation  from the  condemning  authority  or from the Lessor,  if the
condemning  authority  shall not make a separate award, on account of the value,
if any, of Lessee's interest or leasehold estate as it exists  immediately prior
to such  termination.  In the event that only a part of the premises shall be so
taken,  and the part  not so taken  shall be  sufficient  for the  operation  of
Lessee's  business,  Lessee at its option may retain the part not so taken,  but
the rent shall be proportionately  reduced according to the extent to which such
taking shall interfere with or curtail Lessee's business.

10. Quiet Enjoyment: Lessor, for himself, his successors and
assigns, covenants, represents and warrants to Lessee, its
successors and assigns:

      (a) Lessor has good and  sufficient  title to the leased  property  in fee
      simple  absolute,  free and clear of all liens,  encumbrances,  covenants,
      conditions,  restrictions,  easements,  exceptions  or other  limitations,
      except those covenants, conditions' restrictions,  easements or exceptions
      now of record  and  certain  Deeds of Trust to secure  permanent  mortgage
      loans from Prudential Insurance Company.

      (b) So long as  Lessee  shall  pay its rent and not be in  default  in the
      performance  of any of the  covenants  or  conditions  to be  performed by
      Lessee, or any other obligations not expressly set forth herein, which may
      affect Lessor's fee title or reversionary interest in the leased premises,
      Lessee  shall  freely  and  peaceably  have,  hold and  enjoy the sole and
      exclusive use and enjoyment of he leased property, or any part thereof.

      (c) Lessor will at all times save and hold Lessee free and  harmless  from
      any claim,  demand,  cause of action or other act relating to the title to
      the property,  or any part thereof,  or which  interferes  with the quiet,
      peaceful and exclusive use and  enjoyment of the leased  property,  or any
      part thereof,  including but not limited to reasonable costs and attorneys
      fees incurred by Lessee in defending any such  interference  or threatened
      interference therewith.

11.  Assignment  and  Subletting:  Lessee shall have the full right to assign or
sublet its  interest  in this  Lease,  the  premises,  or any  portion  thereof,
provided  that no such  assignment or  subletting  shall  relieve  Lessee of its
liabilities for the full  performance of this Lease and every  provision  hereof
required to be performed by Lessee.  After the initial term of this Lease and in
the event Lessee  desires to assign or sublet its interest in the Lease,  or any
portion of the  premises,  Lessor shall have the right of first  refusal to take
such  assignment  or  subletting  upon the terms and  conditions  offered by any
sub-lessee and acceptable to Lessee.

12. Events of Default:

(a) By Lessee: The occurrence of any of the following shall
constitute a material default and breach of this Lease:

      (1) Any  failure by Lessee to pay the rental  when due for a period of ten
      (10) days after written notice thereof by Lessor to Lessee;

      (2) Any failure by Lessee to make any other payment required to be made by
      Lessee  hereunder  within ten (10) days after  written  notice from Lessor
      specifying  in  detail  the  nature  and  amount of such  payment  and the
      obligation for which is not contested by Lessee;

      (3) The  failure  by  Lessee to  perform  any  obligation  of Lessee to be
      performed  by  Lessee  hereunder  for a period of 120 days  after  written
      notice thereof,  which notice shall specify with  particularity the nature
      of Lessee's default; or (4) The making by Lessee of any general assignment
      for the  benefit  of  creditors;  the  filing  by or  against  Lessee of a
      petition to have Lessee  adjudicated  a bankrupt  (unless in the case of a
      petition  filed against  Lessee,  the same is dismissed  within sixty (60)
      days);  the  appointment  of a  receiver  to  take  possession  of  all or
      substantially  all of Lessee's  assets  located  upon the  premises  where
      possession is not restored to Lessee within sixty (60) days.

b) By Lessor:  The failure by Lessor to perform any  covenant or  obligation  of
Lessor to be performed  hereunder for a period of 120 days after written  notice
thereof,  which notice shall specify with  particularity  the nature of Lessor's
default.

13. Lessor's Remedies Upon Default:  In the event of any such default by Lessee,
as specified in paragraph 12(a) herein,  Lessor shall have the following  rights
and remedies:

a) Lessor shall have the immediate option to terminate this Lease and all rights
of Lessee hereunder by giving written notice of such intention to terminate.  In
such event, Lessor may recover from Lessee:

      (1) The worth at the time of the award of any unpaid rental which had been
      earned at the time of such termination; plus

      (2) The worth at the time of the award of the  amount by which the  unpaid
      rental  would have been  earned  after  termination  until the time of the
      award exceeds the amount of such rental loss Lessee proves could have been
      reasonably avoided; plus

      (3) Any other amount necessary to compensate  Lessor for all the detriment
      proximately  caused by Lessee's  failure to perform its obligations  under
      this Lease or which in the  ordinary  course of things  would be likely to
      result  therefrom.  The term  "rental" as used herein  shall mean the base
      rental  required to be paid by Lessee pursuant to the terms of this Lease.
      As used in  subparagraphs  (1) and (2)  above,  the  "worth at the time of
      award" shall be computed by allowing interest at the rate of seven (7) per
      cent per annum.

b) Lessor shall also have the right, with or without  termination of this Lease,
to re-enter the premises and remove all persons and property therefrom with such
property to be removed and stored in a public warehouse or elsewhere at the cost
and for the account of Lessee.

c) In the event  Lessor  elects to  re-enter as  provided  in  subparagraph  (b)
hereinabove,  or  shall  take  possession  of the  premises  pursuant  to  legal
proceedings or any notice provided by law and Lessor does not elect to terminate
this lease as provided in subparagraph  (a) above,  then Lessor may from time to
time without terminating this Lease either recover all rental as it becomes due,
or relet the  premises  or any part  thereof  for such term or terms and at such
rental or rentals and upon such other terms and conditions as Lessor in its sole
discretion may deem advisable, with the right to make alterations and repairs to
the premises. If Lessor shall elect to so relet, then rentals received by Lessor
from such  reletting  shall be applied:  (1) first to the payment of any cost of
such  reletting;  (2) to the payment of the costs of any alterations and repairs
occasioned by such  reletting  upon the premises;  (3) to the payment of rentals
due and unpaid hereunder, with residue, if any, to be held by Lessor and applied
in payment of future rent as the same may become due and payable.

d) No  re-entry  or taking  possession  of the  premises  by Lessor  pursuant to
subparagraphs  (b) or (c) hereof  shall be construed as an election to terminate
this  lease,  unless a written  notice of such  intention  is given to Lessee or
unless a termination thereof be decreed by any court of competent  jurisdiction.
Notwithstanding  any reletting  without  termination  by Lessor,  because of any
default  by  Lessee,  Lessor  may at any  time  after  such  reletting  elect to
terminate this lease for such default.

14.  Lessee's  Remedies  Upon  Default:  In the event of any  default  by Lessor
hereunder,  Lessee may (a) perform, or cause to be done or performed, any act or
thing to have been  performed  by Lessor  hereunder  and Lessor  shall  repay to
Lessee,  upon  demand,  the  entire  cost and  expense  thereof,  including  any
compensation  to agents or servants of Lessee;  (b) terminate this Lease and all
rights of  Lessor  hereunder  by giving  written  notice  of such  intention  to
terminate  to Lessor;  or (c) with or without  terminating  this Lease,  recover
damages and exercise any other remedies available at law or equity to Lessee.

15.  Liens:  Each  party  shall  during  the  entire  term of this  Lease or any
extension  keep the demised  premises and the property on which the premises are
situated,  free  from  any and all  liens  arising  out of the  work  performed,
materials  furnished,  or obligations incurred by either party in respect to the
premises.

16.  Entry  by  Lessor:  Subject  to  security  restrictions  imposed  by U.  S.
Governmental  Agencies,  Lessee shall permit Lessor and his agents to enter into
and upon said premises at all reasonable times for the purpose of inspecting the
same or for the purpose of maintaining  the buildings in which said premises are
situated, or for the purpose of making repairs,  alterations or addition. to any
other portion of said buildings,  including the erection and maintenance of such
scaffolding,  canopies,  fences and props as may be required, or for the purpose
of posting  non-responsibility notices for alterations,  additions,  repairs, or
for the  purpose of placing  upon the  property in which the said  premises  are
located any usual or ordinary  'for sale" signs,  without any rebate in rent and
without any liability to Lessee for any loss of occupation or quiet enjoyment of
the premises thereby occasioned;  and shall permit Lessor and his agents, at any
time within 180 days prior to the  expiration of this lease,  to place upon said
premises  any usual or  ordinary  "To Let" or "To Lease"  signs and  exhibit the
premises to prospective tenants at reasonable hours.

17. Late Charges:  In the event Lessee fails Go pay any  installment or rent due
hereunder  by the  fifteenth  day of each  month when the same is due then there
shall be added to the  monthly  rental a sum equal to two  percent  (21) of said
monthly rental, said sum to represent a late charge to be paid to Lessor.

18.  Hold Over:  Any  holding  over after the  expiration  of the initial or any
exceeded term of this Lease,  with the consent of Lessor,  shall be construed to
be a tenancy from  month-to-month  at a monthly rental equal to the base monthly
rental as existing  during the preceding term of the Lease,  and shall otherwise
be on the same terms and conditions as herein specified, so far as applicable.

19.  Subordination:  Lessee  agrees that this lease shall,  at the option or any
mortgagee  under or  beneficiary  of any  mortgage  or deed of trust that may be
placed upon or against said premises,  be  subordinated to said mortgage or deed
of trust, to any and all advances to be made thereunder, to any interest secured
thereby,  and all renewals,  replacements and extensions  thereof,  provided the
mortgage  or trust deed shall agree to  recognize,  if Lessee is not in default,
Lessee's interest  hereunder.  In the event any mortgagee or trustee shall elect
to have this lease prior to the lien of its  mortgage  or trust deed,  upon such
mortgagee or trustee  giving  notice in writing to Lessee to that  effect,  this
lease shall be deemed prior to the lien of such  mortgage or trust deed.  Lessee
shall  execute  and  deliver  whatever  instruments  may be  required  for  such
purposes, and failing to do so within ten (10) days from demand in writing, does
hereby make,  constitute and  irrevocably  appoint Lessor,  or assignee,  as its
attorney  in fact in its name,  place and stead so to do. In the event that this
lease becomes  subordinate to any mortgage or deed of trust,  Lessee agrees that
in the  event of  transfer  of title to the  demised  premises  by  Lessor  to a
mortgagee,  trustee or beneficiary under any mortgage or deed of trust or to any
purchaser  therefrom  or  successor  thereto,  this  lease,  if Lessee is not in
default  hereunder,  shall not  terminate,  but Lessee  shall attorn to said new
owner  regardless  of any rule of law to the  contrary  or absence of privity of
contract.  Any  subordination  agreement  shall provide that the Lessee's rights
under this lease shall be honored by the mortgagee,  beneficiary, or trustee, as
long as  Lessee is not in  default,  regardless  of  Lessors  default  under the
obligation to which the lease is subordinate.

20. Broker:  Lessee  warrants that Lessee has not had any dealings with any real
estate broker or agent, in connection  with  negotiating or securing this Lease.
21. Waiver of Subrogation:  Lessor and Lessee shall each,  upon demand,  procure
from and cause each of the  insurers  under all  policies of  insurance,  now or
hereafter,  during the term of this Lease  existing,  and purchased by either or
both, insuring or covering the premises or any portion thereof,  and/or Lessee's
business or operations  thereon, a waiver of all rights of subrogation which the
insurer  under said  policies  might  otherwise,  if at all, have as against the
other  party;  the  foregoing  including,  the  following  being  by  a  way  of
specification,  and not by  limitation,  all policies of fire,  theft and public
liability insurance purchased by either party.

22.  Attorneys'  Fees:  In the event any action is  instituted  by either  party
against the other by reason of the breach or alleged  breach of any  covenant or
condition in this Lease on the part of the other  party,  or arising out of this
Lease,  the party in whose favor final  judgment is entered shall be entitled to
have and recover from the other its actual court costs and reasonable attorneys'
fees to be fixed by the court in such action.

23.  Waiver:  The waiver by either party of any breach or alleged  breach of any
term,  condition,  covenant or agreement herein contained shall not be deemed to
be waiver of such term,  covenant or condition or subsequent breach of the same,
or any other term,  covenant  or  condition  herein  contained.  The  subsequent
acceptance of rent hereunder by Lessor shall not be deemed to be a waiver of any
preceding breach or alleged breach by Lessee of any tern,  covenant or condition
of this Lease,  other than the failure of Lessee to pay a  particular  rental so
accepted.

24. Signs: Subject to all applicable laws and ordinances,  Lessee shall have the
right to erect and  maintain a sign or signs,  concerning  its  business  on the
exterior  wall or right front lawn of the building in which the premises  form a
part.

25. Notices:  All notices to be given by either party shall be given in writing,
personally or by depositing the same in the United States mail, postage prepaid,
and  addressed to the other party at such address as may have been  specified by
prior notice to the other.  Notice to Lessor may be made to any one of the above
named persons.

26. Successors and Assigns: The covenants and conditions herein contained shall,
subject to the provision  hereof as to assignment,  apply to and bind the heirs,
successors, and assigns of each party.

27. Insurance:
a) Fire and Extended Coverage: Lessee shall at its sole cost and expense, obtain
and keep in force during the term hereof,  fire,  extended  coverage,  malicious
mischief and  vandalism  insurance on all buildings  and  improvements  that are
constructed  upon the premises.  The amount of such insurance  shall be not less
than one hundred per cent (100%) of the replacement  value of such buildings and
improvements. Lessee waives as against Lessor any and all claims and demands for
damages,  loss or injury to the buildings and  improvements  hereafter placed or
built upon the Premises  which shall be caused by, or result from fire and other
perils,  events  or  happenings  which  are the  subject  of  extended  coverage
insurance.  Lessee  further  agrees that each such  policy of fire and  extended
coverage  insurance which shall be obtained by Lessee,  whether  required by the
provisions  of  this  Lease  or not,  shall  be mace  expressly  subject  to the
provisions of this paragraph,  and that Lessee's insurers  hereunder shall waive
any right of subrogation as against Lessor.

b) Liability Insurance:  During the term of this Lease, Lessee shall procure and
maintain in full force and effect, bodily injury liability insurance with limits
of not less than Five Hundred Thousand Dollars ($500,000.00) per person and Five
Hundred Thousand Dollars  ($500,000.00) per occurrence  insuring against any and
all  liability of Lessee with  respect to the leased  premises or arising out of
the use, occupancy or maintenance thereof. If so requested in writing by Lessor,
property  damage  liability  insurance with a limit of not less than One Hundred
Thousand Dollars  ($100,000.00)  per action shall be obtained by Lessee.  All or
such insurance shall insure the performance by Lessee of its indemnity agreement
as to liability  for injury or death of persons and injury or damage to property
as herein set forth.  Lessee  waives all claims  against  Lessor for  damages to
goods,  wares and merchandise in, upon or about the premises and for injuries to
persons in or about the premises  from any cause  arising at any time,  with the
exception of the acts or omissions committed by Lessor, its agents,  servants or
representatives.

c) Policy Forms:  All of the  insurance  provided  under this  paragraph and all
renewals  thereof  shall  be  issued  by such  good,  responsible  and  standard
companies as licensed to do business in the State of California. The policies of
insurance  provided for in this paragraph  shall be payable to Lessor and Lessee
and to such other firm, firms,  person or persons as their interests may appear.
Such  insurance  shall be carried in the joint names of Lessor and  Lessee.  All
such  policies  shall  expressly  provide that the policy shall not be cancelled
without  thirty (30) days prior  written  notice to Lessor and Lessee.  Upon the
issuance thereof,  each such policy or duplicate or certificate thereof shall be
delivered to Lessor.

28. Memorandum:  Upon the effective date of this lease, the parties hereto shall
record the memorandum of lease in form attached hereto as Exhibit C.

29. Right of First Refusal:  Prior to Lessor accepting any offer to purchase the
premises or any part  thereof,  or prior to Lessor  making any offer to sell the
premises or any part thereof,  Lessor shall give Lessee  written  notice of such
offer  and  shall  include  in such  notice  the  price  and terms or sale and a
statement  that  Lessor is willing  to sell at that price and on those  terms or
sale. Lessee shall have the option,  which may be exercised by written notice to
Lessor at any time within thirty (30) days from receipt of the Lessor's  notice,
to agree to  purchase  at the price and on the  terms of sale  specified  in the
notice to Lessee; provided,  however, that if such terms provide for an exchange
of property as part or all of the price of the premises,  Lessee shall  purchase
the  property to be exchanged  upon the terms and at the price  specified in the
Notice and  thereafter  exchange  such  property  in  exchange  for the  demised
premises,  on the basis specified in the Notice. If Lessee fails to exercise its
option within the 30-day period,  Lessor shall have 180 days  thereafter to sell
at the price and upon the terms of sale specified in the notice to Lessee.

30. Option to Purchase: Lessor hereby grants to Lessee an option to purchase the
leased  premises,  which option is conditioned  upon this Lease or any extension
thereof  or  replacement  thereof  being in force and  effect  during the option
period.  Such option period shall  commence on the first day of the 21st year of
this Lease or any  extension  thereof and end on the 366th day  thereafter.  The
price at which the leased  premises  may be  purchased  shall be  determined  by
dividing  the annual net rental  (being an amount  equal to 12 times the monthly
base rental  provided  for in Section 3(a)  hereof,  and not  including  taxes,
repairs,  maintenance,  and other similar items), as adjusted in accordance with
section 3(d) hereof, for the 21st lease year by .085. For example,  if the total
annual net rental for the 21st year of the lease term (as adjusted in accordance
with  Section 3(d)) is $540,000,  then the option  price for the said  premises
would be $6,352,941.

The amount of such purchase price, in full in cash or 5% in cash and the balance
in the form of  commitments  from  lending  institutions,  shall be deposited in
escrow to a title  company of Lessee's  choice within thirty (30) days after the
exercise or said option and said transaction shall close within ninety (90) days
of the  exercise of said option.  Lessee  agrees that it will assume the balance
due of any permanent loan financing  encumbering the leased premises at the time
of closing  such  transaction,  or will (if the same is in  accordance  with the
terms of said loan) pay any prepayment penalty in connection with the early full
payment thereof. This option shall terminate on any sale by Lessor or its heirs,
successors. or assigns to a bona fide purchaser, provided that any such purchase
shall have been made after  Lessor's  compliance  with all of the  provisions of
Paragraph  29 hereof,  and  Lessee has  elected  not to  exercise  its rights to
purchase under the provisions of said Paragraph 29. It is  contemplated  that in
the event Lessor desires to enter into a three-party exchange agreement,  Lessee
will,  to the  extent  that it is not to its  detriment,  cooperate  in any such
three-party exchange,  provided however that under no circumstances shall Lessee
be  responsible  for any expense of any kind or nature in  connection  with such
three-party exchange.

31. Miscellaneous:  Where it is herein provided that the consent of either party
shall be obtained,  it is  understood  and agreed that such consent shall not be
unreasonably  withheld.  This lease and any exhibits  attached hereto constitute
the entire  agreement and  understanding  between the parties,  and shall not be
modified,  changed or amended in any  respect  unless in writing  signed by both
parties.

Dated and effective as set forth above.

LESSOR

/s/ John A. Sobrato
JOHN A. SOBRATO

/s/ Susan R. Sobrato
SUSAN R. SOBRATO

/s/ Carl E. Berg
CARL E. BERG

/s/ Mary Ann Berg
MARY ANN BERG

/s/ Ann S. Russo
ANN S. RUSSO

LESSEE

TYMSHARE, INC.
A California Corporation

By /s/ Albert A. Eisenstat


And /s/





EXHIBITS

Exhibit A  Description of Real Property

Exhibit B  Covenants, Conditions, Restrictions, Easements,
           Exceptions and Limitations of Record
Exhibit C  Memorandum of Lease





                                    EXHIBIT A

[Legal Description]





                                    EXHIBIT B

[Title Report]





                                    EXHIBIT C
Recording Requested By:
Mark A. Bertelsen, Esq.
Wilson, Mosher & Sonsini

When Recorded Return To:
Wilson, Mosher & Sonsini
Two Palo Alto Square, Suite 900
Palo Alto, CA 94304
Attention: Mark A. Bertelsen, Esq.

                               MEMORANDUM OF LEASE

THIS MEMORANDUM OF LEASE,  dated as of the 6th day of January,  1978, is made by
and  between  JOHN A.  SOBRATO and SUSAN R.  SOBRATO,  CARL E. BERG and MARY ANN
BERG, and ANN S. RUSSO (herein  collectively  referred to as the "Lessor"),  and
TYMSHARE,  INC.,  a California  corporation  having a place of business at 20705
Valley Green  Drive,  Cupertino,  California  95014  (herein  referred to as the
"Lessee").

For and in consideration of the payment of the rental and the performance of the
covenants  and  undertakings  set forth in the Lease,  Lessor  hereby  leases to
Lessee,  and Lessee hereby hires from Lessor,  on the terms and  conditions  set
forth in that certain lease  entered into by and between the parties  hereto and
dated as of even date  herewith  (herein the  "Lease"),  which are  incorporated
herein by  reference  with the same force and  effect as though  fully set forth
herein,  the premises  located in the City of Cupertino,  County of Santa Clara,
State  of  California,   commonly  known  as  20705  Valley  Green  Drive,  more
particularly  described  in  Schedule A attached  hereto and hereby  made a part
hereof.

The term of this Lease is for an initial term of 15 years, commencing January 1,
1978, and ending December 31, 1992.

Lessee has the right and  option to renew  this  Lease for three (3)  additional
five (5) year terms  commencing  automatically  as of the expiration date of the
initial or any extended  term,  upon Lessee giving Lessor 180 days prior written
notice of its exercise of such option.

Lessee  has the  right of first  refusal  to buy the  premises  prior to  Lessor
accepting  any offer to purchase  said  property  or prior to Lessor  making any
offer to sell said  property,  which right must be exercised  within thirty (30)
days after receipt of Lessor's notice to Lessee of any such offer to purchase or
intention to sell said  property.  If Lessee fails to exercise its option within
said 30-day period,  Lessor shall have 180 days  thereafter to sell at the price
and upon the terms of sale specified in Lessor's notice to Lessee.

Commencing  on the  first day of the 21st  year of this  Lease or any  extension
thereof  and ending on the 366th day  thereafter  Lessee  shall  have  option to
purchase the  premises.  This option shall  terminate on any sale by Lessor to a
bona fide purchaser,  provided that any such purchase shall have been made after
Lessor's  compliance  with all of the  provisions  of  paragraph 29 of the Lease
"Lessee's  right of first  refusal"  and Lessee has elected not to exercise  its
prior right to purchase thereunder.

The purpose of this  Memorandum  of Lease is to give notice of the  existence of
the  tenancy,  and  Lessee's  rights  of first  refusal  on sale and  option  to
purchase,  created  hereby and by the Lease and of the  existence  of the Lease,
which together with this  Memorandum Of Lease  constitute the agreement  between
the parties hereto.

IN WITNESS WHEREOF, Lessor and Lessee have respectively executed this Memorandum
of Lease on February  ___,  1978,  to be  effective as of the day and year first
above written.

LESSOR

John A. Sobrato

Susan R. Sobrato

Carl E. Berg

Mary Ann Berg

Ann S. Russo

LESSEE

TYMSHARE, INC.

By _________________
Vice President





TYMSHARE
20705 Valley Green DriveCupertino, California 95014
Telephone: 408/257-6550

January 5, 1978

   
John A. Sobrato and Susan R. Sobrato
Carl E. Berg and Mary Ann Berg
Ann S. Russo
20700 Valley Green Drive
Cupertino, California 95014
    

Ladies and Gentlemen:

This letter confirms the Agreement between Tymshare, Inc., a corporation (herein
"Tymshare") and you,  relating to the  construction by you and lease by Tymshare
of additional  facilities for Tymshare  corporate  headquarters  on Valley Green
Drive, Cupertino, California.

1. Execution of New Lease.  Attached hereto,  marked Exhibit A, and incorporated
herein by reference,  is a 'arm of Lease to be executed between Tymshare and you
relating to those  facilities  presently leased to Tymshare and those additional
facilities to be constructed pursuant to the terms of this letter agreement. The
new Lease (for a period of fifteen  (15) years,  with three (3) options to renew
for  additional   terms  of  fiche  (5)  years  each)  shall  be  executed  upon
commencement  of  construction  or  the  additional  facilities,  and  shall  be
effective  as of January 1, 1978 or  completion  of  construction,  whichever is
sooner; provided, however, that in the event such additional facilities have not
been completed on or before July 1, 1978, at Tymshare's option, the Lease may be
terminated  and the terms of  Tymshare's  occupancy  of the  presently  occupied
premises  shall be governed by that certain  Lease dated October 24, 1974 by and
between the parties to this letter agreement.

2.  Construction  of  Additional  Facilities.  Upon the execution of this letter
agreement,  you shall,  at your own cost and  expense,  construct or cause to be
constructed in good and workmanlike manner a two-story building of approximately
sixty  thousand  (60,000)  square  feet,  together  with all  necessary  offsite
improvements including paved parking,  sidewalks and landscaping as shown on the
final shell and core plans and  specifications  dated September 22, 1977, and as
revised October 19, 1977. The final interior plans and  specifications  shall be
subject  to  Tymshare's  approval,  which  shall  not be  unreasonably  withheld
provided  that  such  final  plans  are  substantially  in  accordance  with the
preliminary  plans.  You will construct the  improvements  detailed on the final
plans  and  continue  the  same  with  diligence  to   completion,   subject  to
intervention  of  causes  and  contingencies  beyond  your  reasonable  control,
including  but  not  limited  to  accidents,  fire,  flood,  inclement  weather,
government actions, strikes or labor disputes,  shortages of, delay and delivery
or  materials,  wars,  riots or civil  insurrection.  Any  changes  in the plans
subject  to  commencement  of  construction  shall be  approved  in  writing  by
Tymshare. In connection with such construction you agree to assume, pay when due
and  indemnify   Tymshare  against  all  costs  and  expenses  involved  in  the
construction  of  the  improvements  shown  on  the  plans  and  specifications,
including the office  improvements.  After  completion and for the period of the
applicable  warranty,  but in no event less than one year,  you shall remedy all
defects due to faulty  workmanship  or materials,  and when  necessary,  at your
expense enforce any warranty, guaranty or bond covering the building, equipment,
systems, service lines or other equipment,  including heating, air conditioning,
ventilating, electrical, mechanical and plumbing fixtures.

3. Cost of Work. As of the commencement of the construction,  you nave estimated
your costs (including land costs, costs of all improvements to be constructed at
this time,  your profit and  overhead) to be the sum of  $2,251,764,  which when
capitalized  at the agreed rate between us results in a base monthly  rental for
the  additional  facilities of  Twenty-Two  Thousand  Eight  Hundred  Fifty-Five
Dollars  ($22,855.00).  To the extent that actual  costs  incurred by you in the
construction  of the  additional  facilities are less than said sum, the monthly
base  rental  shall be  reduced  in an amount  equal to Ten and  15/100  Dollars
($10.15) per month for each One Thousand Dollars  ($1,000.00) or portion thereof
savings  effected.  In no event,  however,  shall  the  monthly  base  rental be
adjusted upward if such costs exceed your estimated figures.

If the foregoing is in  accordance  with our  understanding,  kindly sign in the
place indicated below.

Yours very truly,

TYMSHARE, Inc.

By /s/ Albert A. Eisenstat

Agreed and accepted as the conditions contained herein.

/s/ John A. Sobrato
JOHN A. SOBRATO

/s/ Susan R. Sobrato
SUSAN R. SOBRATO

/s/ Carl E. Berg
CARL E. BERG

/s/ Mary Ann Berg
MARY ANN BERG

/s/ Ann S. Russo
ANN S. RUSSO





TYMSHARE
20705 Valley Green DriveCupertino, California 95014
Telephone: 408/257-6550

February 17, 1978

John A. Sobrato and
Susan R. SobratoCarl E. Berg and
Mary Ann BergAnn S. Russo20700 Valley Green Drive
Cupertino, California 95014

Ladies and Gentlemen:

This  letter is  intended to confirm the  understanding  and  agreement  between
Tymshare, Inc., a California corporation  ("Tymshare"),  and you relating to the
effect of paragraphs  19, 29 and 30 of that certain Lease dated as of January 6,
1978  between  Tymshare  and you for the  premises  (as  defined in said  Lease)
commonly  known  and  referred  to  as  20705  Valley  Green  Drive,  Cupertino,
California, upon the foreclosure of a deed of trust upon said property.

Tymshare  understands  that upon  completion of  construction  of the additional
facility premises (as defined in said Lease) The Prudential Insurance Company of
America will provide you the permanent  financing for the premises pursuant to a
loan to be secured by a first deed of trust  upon the  property  comprising  the
premises,  said deed of trust to be  executed by you as trustors in favor of The
Prudential Life Insurance Company of America as beneficiary.

Under  paragraph 19 of the Lease,  the Lease may be  subordinated to any deed of
trust placed upon the premises, at the option of the beneficiary of said deed of
trust,  provided  that said deed of trust shall  recognize  Tymshare's  interest
under the Lease if Tymshare i. not in default thereunder,  and provided that any
such  subordination  agreement  shall provide that  Tymshare's  rights under the
Lease shall be honored by the  beneficiary and trustee of any such deed of trust
as long as Tymshare is not in default of the Lease, regardless of any default by
you under the obligation secured by said deed of trust.

Paragraphs 29 and 30 of the Lease give Tymshare a prior right to purchase and an
option to  purchase,  respectively,  the  premises  at such  times and upon such
conditions as set forth therein.

This is to confirm to you that Tymshare  acknowledges and agrees that its rights
under  paragraphs  29  and 30 of  the  Lease  do not  apply  in the  event  of a
foreclosure  of a deed of trust  upon the  premises  (and any  foreclosure  sale
pursuant  thereto),  whether  by  action or under a power of sale in the deed of
trust,  by reason of your  default  in the  obligation  secured  by said deed of
trust. It is understood,  however, that so long as Tymshare is not in default of
the Lease, the Lease shall not be terminated nor shall Tymshare's  possession be
disturbed by reason of your default under or a  foreclosure  of any such deed of
trust, and in the event of a sale, either private or public,  such sale shall be
subject to Tymshare's right to continue in possession and undisturbed  under the
Lease so long as Tymshare is not in default thereunder.

This letter is not intended and shall not be construed to be a  modification  of
or amendment to the Lease,  the terms of which shall  continue to remain in full
force and effect,  but rather is intended  only to clarify the  agreement of the
parties in the event of a foreclosure of a deed of trust upon the premises.

Sincerely,

TYMSHARE, INC.

By /s/ Albert A. Eisenstat
Albert A. Eisenstat
Vice President





                                    AMENDMENT

This  Amendment  shall  modify that certain  lease dated  January 6, 1978 by and
between JOHN A. SOBRATO and SUSAN R.  SOBRATO,  as to an undivided 45% interest,
and CARL E. BERG and MARY ANN BERG, as to an undivided 45% interest,  and ANN S.
RUSSO as to a 10% interest,  herein  collectively  Lessor,  and TYMSHARE,  INC.,
herein Lessee.

The subject leave is hereby amended in the following particular:

Article 1. Premises Leased:

      The  premises  shall be amended to also  include  the  adjacent  one story
      building  to  the  west  commonly  known  as  20605  Valley  Green  Drive,
      comprising approximately 21,000 sq. ft.

Article 2. Rental Consideration:

      Effective February 10, 1979, (a) Monthly Race Rental: The
      monthly base rental shall be increased by the sum of
      $7,350.00 per month to reflect the additional premises
      described above. (c) Rents Adjustment: The adjustment base
      shall be increased by the sum of S7,350.00 to reflect the
      additional premises described above.

Expect as herein  above  expressly  provided,  said lease dated  January 6, 1978
shall remain unchanged.

Consented to by the undersigned on January 30, 1979.

LESSOR

/s/ John A. Sobrato
JOHN A. SOBRATO

/s/ Susan R. Sobrato
SUSAN R. SOBRATO

/s/ Carl E. Berg
CARL E. BERG

/s/ Mary Ann Berg
MARY ANN BERG

/s/ Ann S. Russo
ANN S. RUSSO

LESSEE

TYMSHARE, INC.

By /s/
President





                                  AMENDMENT # 2

This  Amendment  shall  modify that certain  lease dated  January 6, 1978 by and
between JOHN A. SOBRATO and SUSAN R.  SOBRATO,  as to an undivided 45% interest,
and CARL E. BERG and MARY ANN BERG, as to an undivided 45% interest,  and ANN S.
RUSSO as to a 10% interest,  herein  collectively  Lessor,  and TYMSHARE,  INC.,
herein Lessee.

The subject lease is hereby amended in the following particular:

      3.a) The monthly base rental for the initial term of the lease is adjusted
      to a figure of  $50,977.00  ($43,627.00  + $7,350.00)  based upon Lessor's
      actual costs and the inclusion of space referred to in Lease Amendment 11.

Except as herein  above  expressly  provided,  said lease dated  January 6, 1978
shall remain unchanged.

Consented to by the undersigned on 3/17/79.

LESSOR

/s/ John A. Sobrato
JOHN A. SOBRATO

/s/ Susan R. Sobrato
SUSAN R. SOBRATO

/s/ Carl E. Berg
CARL E. BERG

/s/ Mary Ann Berg
MARY ANN BERG

/s/ Ann S. Russo
ANN S. RUSSO

LESSEE

TYMSHARE, INC.
A California Corporation

By /s/





                                  AMENDMENT #3
This  Amendment #3  ("Amendment  #3") shall modify that certain Lease  Agreement
("Lease")  dated  January 6, 1978,  executed by and between  JOHN A. SOBRATO and
SUSAN R. SOBRATO, as to an undivided  forty-five percent (45%) interest,  and to
CARL E. BERG and MARY ANN BERG,  as to an  undivided  forty-five  percent  (45%)
interest,  and to ANN S. RUSSO as to a ten percent (10%)  interest,  all of whom
are predecessors to Carl E. Berg and Mary Ann Berg,  Trustees of the Berg Living
Trust UTA dated May 1, 1981, as to an undivided 81.01% interest,  CLYDE BERG and
NANCY BERG,  Trustees of the Clyde Berg Living  Trust,  UTA dated  December  17,
1981, as to an undivided 11.83% interest,  and CLYDE BERG,  Trustee of Carl Berg
Child's  Trust  UTA  dated  June 2,  1978,  as to an  undivided  7.16%  interest
("Lessor");  and TYMSHARE, INC., predecessor to McDonnell Douglas Corporation, a
Maryland corporation  ("Lessee"),  as amended by that certain Amendment to Lease
executed January 30, 1979, and that certain Amendment #2 to Lease executed March
17, 1979. For purposes  hereof,  the Lease,  as amended by the Amendment and the
Amendment #2 thereto, is referred to herein as the "Amended Lease."

RECITALS

A.  Pursuant to the terms of the Amended  Lease,  Lessor  leases to Lessee,  and
Lessee  leases from Lessor the real  property,  together  with all buildings and
appurtenances  thereto  commonly  known as 20605,  20665 and 20705  Valley Green
Drive, Cupertino, California
(the "Premises").

B.  Pursuant  to the terms of  Paragraphs  3(c)(3)  of the  Amended  Lease,  the
adjustment  of monthly base rental is to be an amount equal to the lesser of (i)
one  hundred  percent  (100%) of the monthly  base rental plus two and  one-half
percent (2.5%) of such monthly base rental per year or a portion  thereof during
the initial term of the Amended Lease or any extension, or (ii) a monthly rental
equal to the "fair  rental  value" of the Premises as of the  effective  date of
such  adjustment.  Pursuant to Paragraph 3(d) of the Amended Lease,  the monthly
base rental for the  Premises has been  adjusted in  accordance  with  Paragraph
3(c)(3)(i) thereof effective June 30, 1985, for the remaining seven and one-half
(7-1/2) years of the initial term of the Amended  Lease.  Paragraph 3(d) further
provides that the monthly base rental is to be readjusted  pursuant to Paragraph
3(c)(3) as of the commencement date of any extended term, if exercised.

D. Some  controversy  has arisen  between  Lessor  and Lessee as to whether  the
calculation  of  the  monthly  base  rental  adjustment  pursuant  to  Paragraph
3(c)(3)(i)  of the Amended  Lease should be made using a  compounded  adjustment
rate or a simple adjustment rate.

E.  Lessor  has  requested,  and  Lessee  has  agreed,  that  in  light  of such
Controversy,  the monthly  base rental for the last seven and  one-half  (7-1/2)
years of the initial term of the Amended Lease, and for each exercised  extended
term thereafter, shall be equal to the respective amounts set forth in Paragraph
1 of this Amendment #3.

F.  Accordingly,  Lessor agrees to reimburse  Lessee for the monthly base rental
paid by Lessee in excess of the monthly  base rental which should have been paid
by Lessee as set forth in this Amendment #3 for the period  commencing from July
1, 1985, and ending June 30. 1997.

NOW,  THEREFORE,  in consideration of the mutual covenants and conditions stated
herein, Lessor and Lessee hereby agree as follows:

1. Rental Adjustment. Paragraph 3(c)(3)(i) of the Amended Lease shall be amended
by  deleting  the  entirety  thereof and  substituting  therefor  the  following
amounts:




                                DURING THE PERIOD            MONTHLY BASE RENTAL
                                                              
Initial Lease Term:     July 1, 1985    - December 31, 1992     $60,944.00
First Extended Term:    January 1, 1993 - December 31, 1997     $72,862.00
Second Extended Term:   January 1, 1998 - December 31, 2002     $82,206.00
Third Extended Term:    January 1, 2003 - December 31, 2007     $92,750.00


2.  Rental  Reimbursement.  Pursuant to the terms of  Paragraph 1 above,  Lessor
shall reimburse to Lessee no later than five (5) days following the execution of
this  Amendment  #3 the sum of  Nine  Thousand  Eight  Hundred  Sixteen  Dollars
($9,816)  constituting  the  difference  between the monthly base rental paid by
Lessee  and the  monthly  base  rental  which  should  have  been paid by Lessee
pursuant to Paragraph 1 above for the period commencing July 1, 1985, and ending
June 30, 1987.

3.  Affirmation  of Amended  Lease.  Except as  provided  herein,  the terms and
conditions of the Amended Lease (and exhibits  thereto) shall remain  unmodified
and in full force and effect.  In the event of any conflict between the terms of
the Amended  Lease (and the exhibits  attached  thereto) and this  Amendment #3,
with regard to Paragraph 3(c)(3)(i),  this Amendment #3 shall control. 4. Entire
Agreement.  This Amendment #3 is the entire  agreement  between the parties with
regard to Paragraph 3(c)(3)(i). This Amendment #3 supersedes and cancels any and
all previous negotiations,  arrangements, agreements and understandings, whether
written or oral,  between  Lessor and its agents and Lessee and its agents  with
respect Paragraph  3(c)(3)(i) only. No addition to, or modification of, any term
or provision of this Amendment #3 shall be effective  until and unless set forth
in a written instrument signed by both Lessor and Lessee.

5.  Attorneys'  Fees.  If any action or  proceeding  is commenced to enforce the
provisions of this Amendment #3, the prevailing  party in such action shall have
the right to recover from the other party its  reasonable  attorneys'  fees,  in
addition to costs and expenses of litigation.

6.  Counterparts.  This  Amendment #3 may be executed in  counterparts,  each of
which shall be deemed an original,  all of which together  shall  constitute one
agreement.

IN WITNESS  WHEREOF,  Lessor and Lessee have executed this  Amendment #3 on this
1st day of July, 1987.

LESSOR:

CARL E. BERG and MARY ANN BERG,  Trustees for Berg Living Trust UTA dated May 1,
1981, as to an undivided 81.01% interest, CLYDE BERG and NANCY BERG, Trustees of
the Clyde Berg Living  Trust,  UTA dated  December 17, 1981,  as to an undivided
11.83%  interest,  and CLYDE BERG,  Trustee of Carl Berg Child's Trust UTA dated
June 2, 1978, as to an undivided 7.16% interest

/s/ Carl E. Berg
CARL E. BERG

/s/ Mary Ann Berg by Carl E. Berg her Attorney in Fact
MARY ANN BERG

/s/ Clyde Berg
CLYDE BERG

/s/ Nancy Berg by Clyde Berg her attorney in Fact
NANCY BERG

LESSEE:

MCDONNELL DOUGLAS CORPORATION,
A Maryland corporation

By /s/
Its





BERG & BERG PROPERTIES
10050 Bandley Drive
Cupertino, California 95014

"Developers of business parks
and Industrial complexes in Palo Alto,
Mountain View, Sunnyvale,
Cupertino & Santa Clara."

This LEASE,  executed in duplicate  at  Cupertino,  California,  this 6th day of
October,  l987, by and between Carl E, Berg & Mary Ann Berg trustees of the Berg
Living Trust, UTA dated May 1, 1981, as to an undivided  81.01% interest,  Clyde
Berg & Nancy Berg,  Trustees of the Clyde Berg Living  Trust UTA dated Dec.  17,
1981, as to an undivided  11.83%,  and Clyde Berg,  Trustee of Carl Berg Child's
Trust UTA dated  June 2,  1978,  as to an  undivided  7.16%  interest  and APPLE
COMPUTER,  INC., a California Corporation hereinafter called respectively Lessor
and Lessee. without regard to number or gender.

USE

WITNESSETH:  That Lessor hereby leases to Lessee,  and Lessee hires from Lessor,
for the purpose of conducting therein office,  research, light manufacturing and
warehouse and for no other purpose without obtaining,  the prior written consent
of Lessor,  those certain premises with the appurtenances,  situated in the City
of Cupertino , County of Santa Clara, State of California, and more Particularly
described as follows. to-wit:

PREMISES

A one story building ("the  premises") of  approximately  23,400 square feet and
appurtent improvements, including parking areas, situated at 10300 Bubb Road.

TERM

The term shall be for FORTY  EIGHT  (48)  months,  commencing  on the 1st day of
December,  l987, and ending on the 30th day of November, l991, at the total rent
or sum of EIGHT  HUNDRED,  FORTY TWO  THOUSAND,  FOUR  HUNDRED  DOLLARS & 00/100
($842,400.00)  Dollars,  payable in monthly  installments of SEVENTEEN THOUSAND,
FIVE HUNDRED & FIFTY DOLLARS ($17,550.00 ) Dollars on or before the first day of
each calendar month during the term hereof.  Said rental shall be paid in lawful
money of the United States of America, without offset or deduction, and shall be
paid to Lessor at such place or places as may be designated from time to time by
Lessor.  Rent for any  period  less than a  calendar  month  shall be a pro rata
portion of the monthly installment.

LATE CHARGES

Lessee  hereby  acknowledges  that late  payment by Lessee to Lessor of rent and
other sums due hereunder  will cause Lessor to incur costs not  contemplated  by
this Lease, the exact amount of which will be extremely  difficult to ascertain.
Such costs include,  but are not limited to, processing and accounting  charges,
and late charges, which may be imposed on Lessor by the terms of any mortgage or
trust deed covering the Premises. Accordingly, if any installment of rent or any
other sum due from Lessee  shall not be received by Lessor or Lessor's  designee
within ten (10) days after such amount shall be due,  Lessee shall pay to Lessor
a late charge  equal to five (5%) percent of such  overdue  amount.  The parties
hereby agree that such late charge represents a fair and reasonable  estimate of
the costs  Lessor will incur by reason of late payment by Lessee  Acceptance  of
such late  charge by Lessor  shall in no event  constitute  a waiver of Lessor's
default with respect to such overdue amount.  nor prevent Lessor from exercising
any of the other rights and remedies granted hereunder.

IT IS FURTHER MUTUALLY AGREED BETWEEN THE PARTIES AS FOLLOWS:

POSSESSION

1. If Lessor, for any reason  whatsoever,  cannot deliver possession of the said
premises  to  Lessee  at the  commencement  of the said  term,  as  hereinbefore
specified,  this lease shall not be void or voidable, nor shall Lessor be liable
to Lessee  for an,  loss or damage  resulting  therefrom;  but in that event the
commencement  and  termination  dates of the lease and all other dates  affected
thereby  shall be  revised  to  conform  to the  date of  Lessor's  delivery  of
possession.  The above is however,  subject to the provision  that the period of
delay of delivery  of the  premises  shall not exceed  Thirty (30) days from the
commencement  date  herein.  If the  period  of delay of  delivery  exceeds  the
foregoing,  Lessee,  at his or its option,  may cancel this Lease and declare it
null and void. Provided further, that if under this Lease, Lessor is required to
do any  construction  or remodeling  work, then the date on which the Lessee has
the right to cancel  shall be  extended  to a later  date by a number of working
days equal to the number of working days during which work  necessary to prepare
the premises for occupancy is delayed by changes  requested by Lessee,  strikes,
boycott, shortage of materials, governmental regulations affecting construction,
acts of God, inclement weather preventing construction,  or other events of like
nature beyond the control and without the  negligence  of Lessor.  If under this
Lease  Lessor is  required  to do any  construction  or  remodeling  work,  then
possession  shall not be deemed tendered and the term shall not start, nor shall
any rentals commence under this Lease,  until the earlier of the following shall
have  occurred:  (a) A  Certificate  of  Occupancy  is  granted  by  the  proper
governmental  agency or, if no  Certificate  of Occupancy be issued by any local
agency,  then upon  certification  by Lessor's  architect or contractor that the
Lessor's construction work has been completed;  or (b) upon the Lessee's opening
for business.

ACCEPTANCE OF PREMISES AND COVENANTS TO SURRENDER

2. By entry hereunder, Lessee accepts the premises as being in good and sanitary
order,  condition and repair and accepts the building and the other improvements
in their present  condition.  Any exceptions to the foregoing must be by written
agreement  executed by Lessor and Lessee.  The Lessee  agrees on the last day of
the term hereof,  or on the sooner  termination of this lease,  to surrender the
premises  unto Lessor in good  condition and repair.  The interior  walls of all
office and warehouse  areas,  the floors of all office and warehouse  areas, all
suspended  ceilings and any carpeting  are to be cleaned.  Lessee also agrees to
surrender unto Lessor all alterations,  additions,  and  improvements  which may
have been made in, to, or on the  premises by Lessee,  except that Lessee  shall
ascertain from Lessor within thirty (30) days before the end of the term of this
lease whether  Lessor  desires to have the premises or any part or parts thereof
restored to their  condition  as of the  commencement  of this Lease;  if Lessor
shall so desire,  then Lessee shall  restore said premises or such part or parts
thereof before the  termination of this Lease at Lessee's sole cost and expense.
Lessee may request that the  alterations  to be  installed  by Lessee  remain in
premises at Lease  termination.  If Lessor agrees to allow said  alterations  to
remain,  Lessee is not required to remove same at Lease termination and they are
considered property of Lessor. Lessee on or before the end of the term or sooner
termination  of this Lease,  shall remove all his or its  personal  property and
trade  fixtures  from the  premises,  and all property  not so removed  shall be
deemed to be abandoned by Lessee.  If the premises be not surrendered at the end
of the term or sooner  termination of this Lease,  Lessee shall indemnify Lessor
against loss or liability  resulting from delay by Lessee in so surrendering the
premises including without limitation,  any claims made by any succeeding tenant
founded on such delay.

USES PROHIBITED

3. Lessee shall not commit,  or suffer to be committed,  any waste upon the said
premises,  or any  nuisance,  or other act or thing  which may disturb the quiet
enjoyment  of any other  tenant in or around the  buildings in which the demised
premises may be located or allow any sale by auction upon the premises, or allow
the  premises to be used for any unlawful  purpose,  or place any loads upon the
floor,  walls, or ceiling which endanger the structure,  or use any machinery or
apparatus which will in any manner vibrate or shake the premises or the building
of which it is a part,  or place any harmful  liquids in the drainage  system of
the building.  No waste materials or refuse shall be dumped upon or permitted to
remain upon any part of the leased premises outside of the building  proper.  No
materials, supplies, equipment, finished products or semi-finished products, raw
materials  or articles of any nature shall be stored upon or permitted to remain
on any portion of the leased premises outside of the buildings proper,  for more
than 15 days. See Addendum, Page 1 for continuance of this Paragraph #3.

ALTERATIONS AND ADDITIONS

4. Lessee shall not make,  or suffer to be made,  any  alteration or addition to
the said premises,  or any part thereof,  without the written  consent of Lessor
first had and obtained by Lessee, which shall not be unreasonably  withheld, any
addition or alteration to the said premises,  except movable furniture and trade
fixtures,  shall  become at once a part of the  realty  and  belong  to  Lessor.
Alterations  and additions  which are not to be deemed as trade  fixtures  shall
include heating, lighting,  electrical systems, air conditioning,  partitioning,
carpeting,  or any other  installation  which has become an integral part of the
leased  premises.  Lessee  agrees  that he or it will not  proceed  to make such
alterations or additions,  after having  obtained  consent from Lessor to do so,
which shall not be unreasonably withheld,  until three (3) days from the receipt
of such consent,  in order that Lessor may post appropriate notices to avoid any
liability  to  contractors  or  material  suppliers  for  payment  for  Lessee's
improvements.  Lessee will at all times  permit such notices to be posted and to
remain  posted  until the  completion  of work.  See Page 1 of the  Addendum for
continuance of this Paragraph #4.

MAINTENANCE OF PREMISES

5.  Lessee  shall,  at his  sole  cost,  keep and  maintain  said  premises  and
appurtenances;  and every part hereof,  including  but not limited to,  glazing,
sidewalks,  parking areas,  plumbing,  electrical systems, roof, exterior walls,
and the  interior of the  premises in good and sanitary  order,  condition,  and
repair.  Lessee is to provide Lessor with a copy of a service  contract  between
Lessee and a licensed  air-conditioning  and heating  contractor  which contract
shall  provide for bimonthly  maintenance  of all air  conditioning  and heating
equipment  at the leased  premises.  Lessee to provide  Lessor  with a copy of a
service  contract,  between  Lessee and a licensed  roof  contractor  to perform
regular  maintenance  to make repairs of the roof.  Lessee is to further pay the
cost of all air-conditioning and heating equipment repairs or replacements which
are  either  excluded  from such  service  contract  or any  existing  equipment
warranties.  All  vinyl  wall  surfaces  are to be  maintained  in an as  good a
condition as when Lessee took possession free of holes,  gouges, or defacements.
Lessee to limit attachments to vinyl wall surfaces  exclusively to V-joints with
no larger than #6 screws. The Lessee agrees to water maintain and replace,  when
necessary,  any  shrubbery  and  landscaping  provided  by Lessor on the  leased
premises. In the event Lessee's premises are only a portion of a building,  then
Lessor  shall pay the cost of any  maintenance  and such cost  allocated  to the
leased  premises shall be prorated on a square footage or other  equitable basis
and  reimbursed to Lessor by Lessee  within ten (10) days after Lessor  provides
evidence of payment.  The Lessee  hereby waives al' right to make repairs at the
expense of Lessor as provided in *Section 1942 of the Civil Code of the State of
California, and all rights provided for by Section 1941 of said Civil Code.

HAZARD INSURANCE

6. Lessee shall not use, or permit said  premises,  or any part  thereof,  to be
used,  for any purpose  other than that for which the said  premises  are hereby
leased;  and no use shall be made or permitted to be made of the said  premises,
nor acts done,  which will cause a cancellation of any insurance policy covering
said building,  or any part thereof, nor shall Lessee sell or permit to be kept,
used or sold, in or about said premises,  any article which may be prohibited by
the standard form of fire insurance policies. Lessee shall, at his sole cost and
expense,  comply with any and all requirements,  pertaining to said premises, of
any  insurance  organization  or  company,  necessary  for  the  maintenance  of
reasonable  fire and public  liability  insurance,  covering  said  building and
appurtenances.  The  Lessee  agrees  to  purchase  and keep in force  fire,  and
extended  coverage  insurance  covering  the leased  premises  in amounts not to
exceed the actual  insurable  value of said  premises as  determined by Lessee's
insurance company's  appraisers,  quotable basis, as calculated by Lessor. It is
understood  and agreed that Lessee's  obligation  under this  paragraph  will be
prorated to reflect the commencement and termination dates of this Lease. Lessor
and Lessee hereby waive any rights each may have against the other on account of
any loss or damage occasioned to the Lessor or the Lessee as the case may be, or
to the  Premises or its  contents,  and which may arise from any risk  generally
covered by fire and extended coverage  insurance.  The parties shall obtain from
their respective insurance companies insuring the property a waiver of any right
of subrogation  which said insurance  company may have against the Lessor or the
Lessee, as the case may be. See Page 1 for continuance of this Paragraph #6.

ABANDONMENT

7. Lessee  shall not vacate or abandon the premises at any time during the term;
and  if  Lessee  shall  abandon,  vacate  of  surrender  said  premises,  or  be
dispossessed by process of law, or otherwise, any personal property belonging to
Lessee and left on the premises  shall be deemed to be abandoned,  at the option
of Lessor, except such property as may be mortgaged to Lessor.

FREE FROM LIENS

8. Lessee shall keep the demised  premises and the property in which the demised
premises are situated,  free from any liens  arising out of any work  performed,
materials furnished, or obligations incurred by Lessee.

COMPLIANCE

9.  Lessee  shall,  at  his  sole  cost  and  expense,  comply  with  all of the
requirements  of all Municipal,  State and Federal  authorities now in force, or
which may  hereafter be in force,  pertaining  to the said  premises,  and shall
faithfully observe in the use of the premises all Municipal ordinances and State
and  Federal  statutes  now in force or which may  hereafter  be it  force.  The
judgement of any court of competent jurisdiction,  or the admission of Lessee in
any action or proceeding  against  Lessee,  whether Lessor be a party thereto or
not,  that Lessee has violated  any such  ordinance or statute in the use of the
premises, shall be conclusive of that fact as between Lessor and Lessee.

LIABILITY INSURANCE

10. Lessee,  as a material part of the  consideration  to be rendered to Lessor,
hereby  waives  all  claims  against  Lessor  to  damages  to  goods,  wares and
merchandise, and all other personal property in, upon or about said premises and
for  injuries  to persons  in or about  said  premises,  except  when  caused by
Lessor's gross negligence,  and Lessee will hold Lessor exempt and harmless from
any damage or Injury to any person,  or o the goods,  wares and  merchandise and
all other  personal  property of any person arising from the use of the premises
by Lessee,  or from the failure of Lessee to keep the premises in good condition
and repair,  as herein provided.  Lessee shall secure and keep in force a public
liability  insurance and property  damage policy  covering the leased  premises.
including parking areas.  insuring the Lessee and naming Lessor as an additional
insured.  A copy of said policy shall be delivered to Lessor and minimum  limits
of coverage  thereof  shall be  $5,000,000.00  combined  coverage  for  multiple
injuries,  and $1,000 000 00 property damage.  and Lessee shall obtain a written
obligation  on the part of the  insurer to notify  Lessor in writing  before any
cancellation thereof.

ADVERTISEMENTS AND SIGNS

11.  Lessee  will not place or permit to be placed,  in,  upon or about the said
premises any unusual or  extraordinary  signs,  or any signs not approved by the
city or other  governing  authority.  The Lessee will not place, or permit to be
placed,  upon the premises,  any signs,  advertisements  or notices  without the
written  consent  of the  Lessor,  and such  consent  will  not be  unreasonably
withheld.  Any  sign so  placed  on the  premises  shall be so  placed  upon the
understanding  and agreement that Lessee will remove same at the  termination of
the  tenancy  herein  created  and repair  any damage or injury to the  premise;
caused  thereby.  and if not so removed by Lessee  then  Lessor may have same so
removed at Lessee's expense.

UTILITIES

12. Lessee shall pay for all water, gas, heat, light, power, telephone and other
utilities supplied to the premises.  Any changes for sewer usage or related fees
shall be the obligation of Lessee and paid for by Lessee.

ATTORNEY'S FEES

13. In case suit should be brought for the  possession of the premises,  for the
recovery  of any sum due  hereunder,  or  because  of the  breach  of any  other
covenant herein, the losing party shall pay to the prevailing party a reasonable
attorney's fee which shall be deemed to have accrued on the commencement of such
action and shall be  enforceable  whether or not such  action is  prosecuted  to
judgment.

DEFAULT

14.1 See Addendum, Page 2 and 3

SURRENDER OF LEASE

14.2 See Addendum, Page 3

14.3 See Addendum, Page 3

14.4 See Addendum, Page 3 and 4

14.5 See Addendum, Page 4

14.6 See Addendum, Page 4 and 5

SURRENDER OF LEASE

15. The  voluntary  or other  surrender  of this  Lease by  Lessee,  or a mutual
cancellation  thereof,  shall not work a merger,  and  shall,  at the  option of
Lessor, terminate all or any existing subleases or subtenancies,  or may, at the
option of Lessor,  operate as an assignment to him of any or all such  subleases
or subtenancies.

TAXES

16. Lessee shall be liable for all taxes levied  against  personal  property and
trade or business  fixtures,  and agrees to pay, as additional  rental, all real
estate taxes and special assessment  installments as they appear on the City and
County tax bills  during the Lease  term,  and as they become due. If said taxes
and assessments are assessed  against the entire building and building site, and
this  lease does not cover  entire  building  or  building  site,  the taxes and
assessment installments allocated to the leased premises shall be pro-rated on a
square  footage  or other  equitable  basis,  as  calculated  by  Lessor.  It is
understood  and agreed that Lessee's  obligation  under this  paragraph  will be
pro-rated to reflect the commencement  and termination  dates of this Lease. See
Paragraph #33 for Tax Clause.

NOTICES

17. All notices given to Lessee must be given in writing by depositing  the same
in the  United  States  certified  or  registered  mail,  postage  prepaid,  and
addressed  to Lessee at the said  premises,  whether or not Lessee has  departed
from abandoned or vacated the premises. See Addendum,  Page 5 for continuance of
this paragraph #17.

ENTRY BY LESSOR

18.  Lessee  shall  permit  Lessor  and his  agents to enter  into and upon said
premises upon 24 hours notice subject to any security  regulations of Lessee for
the  purpose  of  inspecting  the same or for the  purpose  of  maintaining  the
building  in which said  premises  are  situated,  or for the  purpose of making
repairs,  alterations  or  additions  to any  other  portion  of said  building,
including the erection and maintenance of such scaffolding, canopies, fences and
props as may be required without any rebate of rent and without any liability to
Lessee for any loss of  occupation  or quiet  enjoyment of the premises  thereby
occasioned;  and shall permit  Lessor and his agents,  at any time within ninety
(90) days prior to the expiration of this Lease, to place upon said premises any
usual or ordinary  "For Sale" or "to lease"  signs and  exhibit the  premises to
prospective tenants at reasonable hours.

DESTRUCTION OF PREMISES

19. In the event of a partial  destruction of the said premises  during the said
term from any cause,  Lessor  shall  forthwith  repair the same,  provided  such
repairs  can be made  within One  Hundred  Eighty  (180) days under the laws and
regulations of State, Federal, County or Municipal authorities, but such partial
destruction  shall in no way annul or void this lease,  except that Lessee shall
be entitled to a  proportionate  reduction  of rent while such repairs are being
made,  such  proportionate  reduction  to be based  upon the extent to which the
making of such repairs shall interfere with the business carried on by Lessee in
the said  premises.  If such repairs  cannot be made in One Hundred Eighty (180)
days, Lessor may, at his option,  make same within a reasonable time, this Lease
continuing in full force and effect and the rent to be  proportionately  reduced
as aforesaid in this  paragraph  provided.  In the event that Lessor does not so
elect to make such  repairs  which  cannot be made in One Hundred  Eighty  (180)
days, or such repairs cannot be made under such laws and regulations, this Lease
may be  terminated  at the option of either  party.  In  respect to any  partial
destruction which Lessor is obligated to repair or may elect to repair under the
terms of this  paragraph,  the provision of Section 1932,  Subdivision 2, and of
Section 1933,  Subdivision  4, of the Civil Code of the State of California  are
waived by Lessee.  In the event that the building in which the demised  premises
may be  situated  be  destroyed  to the  extent of not less than  33-1/3% of the
replacement cost thereof.  Lessor may elect to terminate this Lease, whether the
demised premises be injured or not. A total destruction of the building in which
the said premises may be situated shall  terminate  this Lease.  In the event of
any  dispute  between  Lessor  and Lessee  relative  to the  provisions  of this
paragraph, they shall each select an arbitrator, the two arbitrators so selected
shall select a third arbitrator and the three arbitrators so selected shall hear
and  determine the  controversy  and their  decision  thereon shall be final and
binding upon both Lessor and Lessee, who shall bear the cost of such arbitration
equally between them.

ASSIGNMENT AND SUBLETTING

20. Lessee shall not assign this Lease, or any interest  therein,  and shall not
sublet  the  said  premises  or any part  thereof,  or any  right  or  privilege
appurtenant  thereto,  or suffer  any other  person (a bona fide  subsidiary  or
affiliate of Lessee excepted) to occupy or use the said premises, or any portion
thereof,  without the written  consent of Lessor first had and  obtained,  and a
consent to one  assignment,  subletting,  occupation or use by any other person,
shall not be deemed to be a consent to any  subsequent  assignment,  subletting,
occupation or use by another person.  Any such assignment or subletting  without
such consent shall be void,  and shall,  at the option of the Lessor,  terminate
this Lease,  providing Lessor has not unreasonably  withheld such consent.  This
Lease  shall not,  nor shall any  interest  therein,  be  assignable,  as to the
interest of Lessee,  by operation of law, without the written consent of Lessor.
If Lessee  desires to assign  its rights  under this Lease or to sublet all or a
portion of the demised  premises to a party other than a bona fide subsidiary or
affiliate of Lessee,  Lessee shall first notify Lessor of the proposed terms and
conditions  of such  assignment  or  subletting.  Lessor shall have the right of
first refusal to enter into a direct Lessor-Lessee  relationship with such party
under  such  proposed  terms and  conditions.  in which  event  Lessee  shall be
relieved  of its  obligations  hereunder  to  the  extent  of the  Lessor-Lessee
relationship  entered into between Lessor and such third party.  Lessee does not
need Lessor's  approval if Lessee is subletting less than 50% (fifty percent) of
the premises.


CONDEMNATION

21. If any part of the  premises  shall be taken for any public or  quasi-public
use, under any statute or by right of eminent domain or private purchase in lieu
thereof,  and  a  part  thereof  remains  which  is  susceptible  of  occupation
hereunder,  this Lease shall as to the part so taken,  terminate  as of the date
title shall vest in the condemnor or purchaser,  and the rent pay able hereunder
shall be adjusted so that the Lessee shall be required to pay for the  remainder
of the term only such  portion  of such rent as the value of the part  remaining
after  such  taking  bears to the  value of the  entire  premises  prior to such
taking;  but in such event  Lessor or Lessee  shall have the option to terminate
this Lease as of the date when title to the part so taken vests in the condemnor
or  purchaser.  If all of the  premises,  or such part  thereof be taken so that
there does not remain, portion susceptible for occupation hereunder,  this Lease
shall  thereupon  terminate.  If a part  or all of the  premises  be  taken  all
compensation  awarded  upon such  taking  shall go to the  Lessor and the Lessee
shall have no claim thereto.

EFFECTS OF CONVEYANCE

22. The term  "Lessor" as used in this Lease.  means only the owner for the time
being of the land and building,  containing the promises,  so that, in the event
of any  sale of said  land  or  building,  or in the  event  of a Lease  of said
building,  the Lessor shall be and hereby is entirely  freed and relieved of all
covenants and  obligations of the Lessor  hereunder,  and it shall be deemed and
construed,  without further  agreement  between the parties and the purchaser at
any such sale,  or the Lessee o! the  building,  that the purchaser or Lessee of
the  building  has  assumed  and agreed to carry out any and all  covenants  ant
obligations of the Lessor  hereunder.  It any security be given by the Lessee to
secure the faithful  performance  of all or any o the covenants of this Lease on
the part of Lessee,  the Lessor may transfer and deliver the security,  as such,
to the purchaser at any such sale or the Lessee of the  building,  and thereupon
the Lessor shall be discharged from any further liability in reference thereto.

SUBORDINATION

23. This Lease,  in the event  Lessor so  notifies  Lessee in writing,  shall be
subordinate  to any  ground  Lease,  deed of trust or  other  hypothecation  for
security  now or hereafter  placed upon the real  property of which the Premises
are a part and to any and all  advances  made on the  security  thereof  and too
renewals,  modifications,  replacements and extensions thereof. Lessee agrees to
promptly  execute any reasonable  documents  which may be required to effectuate
such subordination.  Notwithstanding such subordination, Lessee's right to quiet
possession  of the  Premises  shall not be disturbed if Lessee is not in default
and so long as Lessee  shall pay the rent and  observe  and  perform  all of the
provisions of this Lease.

WAIVER

24.  The  waiver by Lessor of any  breach of any term,  covenant  or  condition,
herein  contained  shall not be deemed to be waiver of such  term,  covenant  or
condition or any  subsequent  breach of the same or any other term,  covenant or
condition  therein  contained.  The  subsequent  acceptance of rent hereunder by
Lessor shall not be deemed to be a waiver of any  preceding  breach by Lessee of
any term,  covenant or condition of this Lease, other than the failure of Lessee
to pay the particular  rental so accepted,  regardless of Lessor's  knowledge of
such preceding breach at the time of acceptance of such rent.

HOLDING OVER

25. Any holding over after the expiration of the said term,  with the consent of
Lessor,  shall be construed to be a tenancy from month to month,  at a rental to
be  negotiated by Lessor and Lessee prior to the  expiration  of said term,  and
shall  otherwise  be on the terms and  conditions  herein  specified,  so far as
applicable, not to exceed 125% of rent.

SUCCESSORS AND ASSIGNS

26.  The  covenants  and  conditions  herein  contained  shall,  subject  to the
provisions as to assignment, apply to and bind the heirs, successors, executors,
administrators  and assigns of all of the parties hereto; and all of the parties
hereto shall be jointly and severally liable hereunder.

ESTOPPEL CERTIFICATES

27.  Lessee shall at any time during the term of this Lease,  upon not less than
twenty (20) days prior written notice from Lessor, execute and deliver to Lessor
a statement  in writing  certifying  that this Lease is  unmodified  and in full
force and effect (or, if modified,  stating the nature of such modification) and
the date to which the rent and other  charges are paid in advance,  if any,  and
acknowledging that there are not, to Lessee's knowledge, any uncured defaults on
the part of Lessor  hereunder or  specifying  such defaults if they are claimed.
Any such statement may be conclusively relied upon by any prospective  purchaser
or  encumbrances  of the Premises.  Lessee's  failure to deliver such  statement
within such time shall be  conclusive  upon the Lessee that (a) this Lease is in
full force and effect,  without  modification  except as may be  represented  by
Lessor; (b) there are no uncured defaults in Lessor's performance.

TIME

28. Time is of the essence of this Lease.

MARGINAL CAPTIONS

29. The marginal  headings or titles to the  paragraphs  of this Lease are not a
part  of  this  Lease  and  shall  have  no  effect  upon  the  construction  or
interpretation  of  any  part  thereof.  This  instrument  contains  all  of the
agreements  and  conditions  made  between  the  parties  hereto  and may not be
modified orally or in any other manner than by an agreement in writing signed by
all of the parties hereto or their respective  successors in interest.  Articles
30 through 34 are included herein by this reference.

IN WITNESS WHEREOF,  Lessor and Lessee have executed these presents, the day and
year first above written.

LESSOR

/s/ Carl E. Berg, Trustee

/s/ Mary Ann Berg, Trustee, by Carl E. Berg her Attorney in Fact

/s/ Clyde Berg, Trustee, by Carl E. Berg his Attorney in Fact

/s/ Nancy Berg, Trustee, by Carl E. Berg her Attorney in Fact

/s/ Carl Berg Child Trust by Clyde Berg, Trustee, by Carl E. Berg
his Attorney in Fact

LESSEE

APPLE COMPUTER, INC. a California Corp.

By: /s/
Its: Vice President





                                ADDENDUM TO LEASE
Dated October 6th, 1987
By and Between
and  APPLE  COMPUTER  SYSTEMS,  INC.  Paragraph  #3 of Lease  agreement,  page 2
continued:  Lessee agrees that it shall not store or use any hazardous waste, as
that term is defined in this Lease,  in its use of the  premises  without  first
obtaining  the prior written  consent of the Lessor,  which consent shall not be
unreasonably withheld, provided adequate assurances against loss because of such
activities is provided to Lessor,  including but not limited to any  appropriate
modification of Paragraph #34 set forth in the Addendum to this Lease.

Paragraph #4 of Lease agreement, page 2 continued:

Notwithstanding  the  foregoing,  Lessee accepts the premises "as is" subject to
electrical mechanical,  plumbing,  etc. systems plus roof being in good operable
condition.  Lessee  intends  to  remove  most  or all of the  existing  interior
partitions and carpet;  re-carpet and paint; plus general construction upgrading
of the space at Lessee's sole expense.  Lessee shall provide  Lessor with a plan
of the new  interior  improvements,  which  will be  approved  by  Lessor,  such
approval shall not be unreasonably withheld.  Lessee will complete, as proposed,
improvements  in a timely  manner.  Said  improvements  will become  property of
Lessor at Lease termination.  Lessee to provide Lessor with complete copy of "as
built" plans. Lessee may make alterations of no more than $10,000.00 without the
consent of the Lessor.

Paragraph #6 of Lease agreement, Page 3 continued:

Lessee  shall  maintain  at its sole  cost,  in full  force  and  effect  rental
abatement  insurance  against  abatement  or-  loss of hen t in case of fir-e or
other-  casualty,  in an amount at least equal to the amount of the Rent payable
by Lessee  during the next ensuing one (1) year,  as  reasonably  determined  by
Lessor.  Lessee  to  reimburse  Lessor  for full cost of said  rental  abatement
insurance.  Where  Lessee is  responsible  for  purchasing  and keeping in force
insurance in this paragraph,  Lessee's insurance  cover-age shall name Lessor as
an  additional  insured  and  provide  Lessor  with  an  endorsed  copy  of said
insurance.

14.1 EVENTS OF DEFAULT

If Lessee fails to make any payment of any sum due under this Lease for (10) ten
days  after  receipt  by Lessee of  written  notice  from  lessor,  or if Lessee
breaches any other term of this Lease and fails to cure such breach  within (30)
thirsty  days after  receipt of written  notice  from  Lessor' or, if such bract
cannot be cured  within  such (act)  thirty day period,  and if Lesser  fails to
commence such cure within (go) thirty day period,  and  thereinafter  diligently
proceeds to clime it, or if Lessee's interest herein,  or, any part thereof,  is
assigned or,  transferred,  either voluntarily or by operation of law (except as
expressly  permitted  by other  provisions  of this Lease),  including,  without
limitation,  the  filing of a  petition  by or  against  Lessee or any member of
Lessee if Lessee is a  partnership  or joint  venture,  under any  insolvency or
bankruptcy laws, or if Lessee makes a general  assignment for the benefit of its
creditors,  then ant such  events  shall  constitute  a breach of this  Lease by
Lessee and Lessor may, at its option,  elect the  remedies  specified  in either
subparagraph (a) or (b) below.

(a) Lessor may  repossess  the  Premises  and remove all  per-sons  and property
therefrom. If Lessor repossesses the Premises because of a breach of this Lease,
this Lease shall terminate and Lessor may recover from Lessee:

      (1) the  worth  at the time of award of the  unpaid  rent  which  has been
      earned at the time of termination  including  interest thereon at the rate
      equal to five  percent  (5%) above the  discount  rate  charged to members
      banks by the Federal Reserve Bank of San Francisco until paid:

      (2) the worth at the time of award of the amount by which the unpaid  rent
      which would have been  earned  after  termination  until the time of award
      exceeds the amount of such rental loss that Lessee  proves could have been
      reasonably  avoided  including  interest thereon at the rate equal to five
      percent  (5%)  above the  discount  rate  charged  to member  banks by the
      Federal Reserve Bank of San Francisco until paid;

      (3) the worth at the time of award of the amount by which the unpaid  rent
      for the balance of the term after the time of award  exceeds the amount of
      such  rental  loss  for the  same  period  that  Lessee  proves  could  be
      reasonably avoided; and

      (4) any other account necessary to compensate Lessor for all the detriment
      approximately  caused by Lessee's failure to perform its obligations under
      this Lease or which in the  ordinary  course of things  would be likely to
      result therefrom.

(b) If Lessor does not repossess the Premises, then this Lease shall continue in
effect for so long as Lessor does not terminate Lessee's right to possession and
Lessor may enforce all of its rights and  remedies  under this Lease,  including
the right to recover the rent and other sums due from Lessee hereunder.  For the
purposes of this Article 14 the following do not constitute  repossession of the
Premises by Lessor or a termination of the lease by Lessor:

     (1) Acts of maintenance or preservation by Lessor or efforts
     by Lessor to relet the Premises; or

     (2) The appointment of a receiver by Lessor to protect  Lessor's  interests
     under this Lease.

14.2 TIME OF AWARD

As used  herein,  the term "time of award" shall mean either the date upon which
Lessee pays to Lessor the amount recoverable by Lessors as hereinabove set forth
or the date of entry of any  determination,  order or  judgment  of any court or
other legally  constituted  body determining the amount  recoverable,  whichever
first occurs.

14.3 LEASE REMAINS IN EFFECT

Should Lessor,  following any breach or default of this Lease by Lessee elect to
continue this Lease in full force and effect, with Lessee retaining the right to
possession  of the  Premises  (notwithstanding  the fact  that  Lessee  may have
abandoned the Premises)  then,  besides all other rights and remedies Lessor may
have at law or  equity,  Lesson  shall  have  the  right to  enforce  all of the
Lessor's  rights and remedies  under this Lease,  including  but not limited to,
Lessor's  right to recover  the Fixed  Rental  and other sums  payable by Lessee
hereunder as they become due under this Lease. Notwithstanding any such election
to have this  Lease  remain in full  force and  effect,  Lessor  may at any time
thereafter  elect,  by written  notice to Lessee,  to  terminate  this Lease and
Lessee's right to possession of the Premises for any previous  breach or default
which remains uncured, or for any subsequent breach or default.

14.4 LESSOR'S ADDITIONAL RIGHTS

In  addition to any  specific  rights  given to Lessor  under this Lease to cure
Lessee's breaches,  if Lessee fails to perform any of its obligations under this
Lease and such failure  continues  after notice  thereof is given in  accordance
with  Section 14.1 (ii) and (iii),  then in  addition  to all other  rights and
remedies of Lessor under this Lease and at law or equity,  Lessor may (but shall
not be  obligated  to) cure  such  breach or behalf  Lessee  and upon  demand by
Lessor, Lessee shall promptly pay to Lessor the costs and expenses of such cure,
including but not limited to,  reasonable  attorneys' fees incurred by Lessor in
curing such breach on behalf of Lessee.  When Lessor  makes  demand for payment,
Lessor  shall  furnish  Lessee an itemized  statement  of the costs and expenses
incurred for cure.  All costs and expenses  incurred or advanced by Lessor under
any  provision of this Lease to cure any  non-monetary  default by Lessee of its
obligations  under this Lease shall bear interest  from the date Lessor  demands
payment  thereof by written  notice to Lessee until payment in full by Lessee at
the rate of five percent (5%) above the discount rate charged to member banks by
the Federal  Reserve Bank of San Francisco,  or the maximum rate allowed by law,
whichever is lower.

14.5 LESSOR'S LIABILITY

Lessee shall have recourse to all  appropriate  legal and equitable  remedies in
the event of a breach of this Lease by Lessor,  provided  however,  that  Lessee
shall first  provide to Lessor at least thirty (30) days prior  written  notice,
specifying with  particularity  the breach claimed it Lessee and allowing Lessor
the right to cure such  breach  during the thirty (30) day period or such longer
period as may be reasonably  required to cure such breach,  provided that Lessor
commences  such cure  during  said  period of  thirty  (30) days and  diligently
prosecutes  such cure to  completion,  Lessor  shall have no  liability  for any
consequential damage.

14.6 LESSEE'S ADDITIONAL RIGHTS

If  Lessor  fails  to  perform  any  of  its  obligations   under  Paragraph  19
(Destruction) of this Lease, and such failure  continues after notice thereof is
given in accordance  with Sector 14.1,  then in addition to all other rights and
remedies of Lessee  under this Lease and at law or equity  Lessee may (but shall
not be  obligated  to) cure finch  breach on behalf of Lessor and upon demand by
Lessee, Lessor shall promptly pay to Lessee the costs and expenses of such cure.
Should  Lessor fail  promptly to pay such costs and expense,  Lessee may recover
said  amounts by  appropriate  local  proceedings.  When Lessee makes demand for
payment,  Lessee  shall  furnish  Lessor an itemized  statement of the costs and
expense,  incurred  for cure.  All costs and  expenses  incurred  or advanced by
Lessee  under any  provision of this Lease to cure any defaults by Lessor of its
obligations  under this Lease to cure any defaults by Lessor of its  obligations
under this Lease  shall  bear  interest  from the date  Lessee  demands  payment
thereof by written  notice to Lessor until Payment in full by Lessor at the rate
of five  percent  (5%) above the  discount  rate  charged to member banks by the
Federal  Reserve  Bank of San  Francisco.  or the maximum  rate  allowed by law,
whichever is lower.

Paragraph # 17 of Lease agreement, Page 4 continued.

Notices:  All notices shall be given to Lessor and Lessee at the address  listed
below:

Lessor:
Berg & Berg Developers
10050 Bandley Drive
Cupertino, CA  95014

Lessee:
Apple Computer, Inc.
20525 Mariani Avenue
Cupertino, CA  95014
Attn: Real Estate Dept.

30. Early Entry.

Thirty (30) days prior to the commencement  date of the Lease Term.  Lessee may,
at Lessee's sole risk, enter the Premises and install  interior  improvements as
defined in Paragraph # 4 herein, trade fixtures,  and equipment in the Premises;
provided, however, that (a) Lessee shall execute an indemnity agreement in favor
of Lessor in form and substance  reasonably  satisfactory to Lessor;  (b) Lessee
shall pay for and provide  evidence of  insurance  satisfactory  to Lessor;  and
Lessee shall pay utility charges reasonably allocated by Lessor to Lessee.

31. Damage or Destruction.

If,  during the term,  the premises for the building and other  improvements  in
which the  premises  are  located are totally or  partially  destroyer  from any
cause,  rendering  the premises  totally or partially  inaccessible  or unusable
Lessee shall  restore the premises or the  building  and other  improvements  in
which the premises are in immediately before destruction.

2. Option to Extend

a. Option. At the expiration of the original term hereof,  Lessee may extend the
term  of  this  Lease  for an  additional  period  of  twenty-four  (24)  months
commencing  immediately  following the Expiration  Date (the  "Extended  Term").
Lessee  shall  exercise  this  option,  if at all,  by giving  Lessor  notice of
Lessee's  intention to do so at least one hundred twenty (120) days prior to the
Expiration  Date.  In no event  shall any  purported  exercise of such option by
Lessee be effective  if an Event of Default (as defined in Paragraph  14) exists
at the time of such  exercise or at the time the Extended  Term would  otherwise
have commenced. Such Extended Term shall be upon all of the terms and conditions
hereof,  except that the monthly rental and method of rental  adjustment for the
Extended  Term shall be  determined  as set forth  below.  The option  rights of
Lessee under this  paragraph are granted for Lessee's  personal  benefit and may
not be assigned or transferred by Lessee.

b. Extended Term Rent. As of the  commencement of the Extended Term, the monthly
rent for the Extended Term shall be subject to  negotiation  between  Lessor and
Lessee,  with an effort to determine a fair market rental for the  Premises,  as
improved.  In the event the parties fail to agree upon the amount of the monthly
rent for the Extended Term prior to commencement  thereof,  the monthly Rent for
the Extended Term shall be  determined by appraisal in the manner  hereafter set
forth;  provided,  however,  that in no event  shall  the  monthly  rent for the
Extended Term be less than the monthly Rent payable  hereunder for the last full
month of the Lease term immediately preceding commencement of the Extended Term.

In the event it becomes  necessary  under this  paragraph to determine  the fair
market  monthly  rent and the method of rental  adjustment  of the  Premises  by
appraisal,  Lessor and Lessee  each shall  appoint a real estate  appraiser  who
shall be a member of the American Institute of Real Estate Appraisers  ("AIREA")
and such  appraisers  shall each  determine the fair market monthly rent for the
Premises,  and the method of rental  adjustment taking into account the value of
the Premises and the amenities  provided by the Outside Areas,  the Common Areas
and the  Building  and  prevailing  comparable  rentals  and  rental  adjustment
practices in the area. Such appraisers  shall,  within twenty (20) business days
after their  appointment,  complete their  appraisals and submit their appraisal
reports to Lessor and Lessee.  If the fair market  monthly  rent of the Premises
established in the two (2) appraisals varies by five percent (5%) or less of the
higher rental, the average of the two shell be controlling.  If said fair market
monthly rent varies by more than five percent  (5%) of the higher  rental,  said
appraisers,  within ten (10) days after submission of the last appraisal,  shall
appoint a third  appraiser who shall be a member of the AIREA and who shall also
be  experienced  in the appraisal of rental value and  adjustment  practices for
commercial  properties  in the vicinity of the  Premises.  Such third  appraiser
shell  within  twenty (20)  business  days after his  appointment,  determine by
appraisal the fair market  monthly rent of the Premises  sating into account the
same factors  referred to above,  and submit his appraisal  report to Lessor and
Lessee.  The fair market monthly rent  determined by the third appraiser for the
Premises  shall be  controlling,  unless  it is less  than that set forth in the
lower appraisal previously  obtained,  in which case the value set forth in said
lower  appraisal  shall be  controlling,  or unless it is greater  than that set
forts in the higher appraisal  previously  obtained in which case the rental set
forth in said higher  appraisal  shall be  controlling.  The method of adjusting
rental periodically,  including the manner and timing of such adjustments, shall
be as  determined  by the  initial  two  appraisers,  if they  agree on a single
method;  otherwise,  it shall be as determined by the third appraiser. If either
Lessor or Lessee fails to appoint an appraiser,  or if an appraiser appointed by
either of them fails,  after his appointment to submit his appraisal  within the
requited period in accordance with the foregoing, the appraisal submitted by the
appraiser  properly  appointed  and timely  submitting  his  appraisal  shall be
controlling.  If the two appraisers appointed by Lessor and Lessee are unable to
agree upon a third  appraiser  within the required period in accordance with the
foregoing,  application  shall be made  within  twenty (20) days  thereafter  by
either Lessor or Lessee to AIREA, which shall appoint a member of said institute
willing  to  serve  as  appraiser.   The  cost  of  all  appraisals  under  this
subparagraph  shall be borne  equally  by Lessor  and  Lessee.  The rent for the
Extended Term will be equal to 92.5% the above fait market monthly rent.

c. Second Option to Extend.  Provided Lessee has timely  exercised the option to
extend  provided  in  subparagraph  a above,  Lessee may extend the term of this
Lease  for  one  additional   period  of  twenty-four  (24)  months   commencing
immediately  following  the last day of the first  Extended  Term  (the  "Second
Extended Term").  Lessee shall exercise this option, if at all, by giving Lessor
notice of Lessee's  intention  to do so at least one hundred  twenty (120) darts
prior to the date of  expiration  of the  Extended  Term.  In no event shall any
purported  exercise of such option by Lessee be effective if an Event of Default
(as definer in paragraph 14.1 exists at the time of such exercise or at the time
the Second  Extended Term would have otherwise  commenced.  The Second  Extended
Term  shall be upon all of the  terms  and  conditions  hereof  except  that the
monthly rent and method of rental  adjustment for the Second Extended Term shall
be determined in accordance  smith the  provisions of paragraph b, assuming that
"Extended Term" as used in said  subparagraph  means the "Second Extended Term."
Unless  expressly  mentioned  and  approved  in the  written  consent  of Lessor
referred to in  Paragraph  20 of this Lease,  the option  rights of Lessee under
this paragraph are granted for Lessee's personal benefit and may not be assigned
or transferred by Lessee.

33. Taxes  Lessee,  at its cost,  shall have the right,  at ant time,  to seek a
reduction  in the  assessed  valuation  of the  premises  or to contest any real
property  taxes that are to be paid by Lessee.  If Lessee  seeks a reduction  or
contests the real property  taxes,  the failure on Lessee's part to pay the real
property  taxes shall not  constitute a default as long as Lessee  complies with
the provisions of this paragraph and posts a bone or Letter of Credit payable to
Lessor for all  delinquent  taxes and  proposed  penalties.  Lessor shall not be
required  to join in any  proceeding  or contest  brought  by Lessee  unless the
provisions of any law requires  that the  proceeding or contest be brought by or
in the name of Lessor or any owner of the premises.  In that case,  Lessor shall
join in the proceeding or contest or permit it to be brought in Lessor's name as
long as Lessor is not required to bear any cost. Lessee, on final  determination
of the proceeding or contest, shall immediately pay or discharge any decision or
judgment  rendered,  together  with all costs,  changes,  interest and penalties
incidental  to the  decision or  judgment.  Outing the initial four year term of
this lease, but not during any option extensions,  Apple shall. not be obligated
to pay for any  property  tax  increases  that incur as the  direct  result of a
transfer or the property from one entity  controlled  by Berg to another  entity
controlled by Berg.  This clause is null and void if Lessor should sell property
to an  independent  third  party.  Tax bills will be sent to the  address in the
Notice section, Article #17.

If at any time  during  the term of this lease a tax or excise on rents or other
tax, however described, is levied or assessed against Lessor, as a substitute in
whole or in part for real  property  taxes  assessed or imposed on the  premises
Lessee  shall pay before  delinquency  such tax or excise on rents or such other
tax to the  extent  that  such  tax or  excise  on rents  or such  other  tax is
substitute in whole or in part for real property  taxes on the premises.  In the
event that a tax:, or excise on rents is levied or assessed against Lessor, as a
substitute  in whole or in part for taxes  assessed or imposed on the  premises,
and the taxing authority takes the position that Lessee cannot pay and discharge
such tax on behalf  or  Lessor,  then at the  election  of  Lessor,  Lessor  may
increase the rent charged  hereunder by the exact portion of such tax which is a
substitute  in whole or in part for real  property  taxes on the  premises,  and
Lessee  agrees to pay said portion in  additional  rent.  Lessor agrees that the
additional rents if any, collected per this paragraph 33 shall not be subject to
the  incremental  rental  increases as provided in Paragraph 32. Lessee  further
agrees  to pay any  sewer or water  usage  fees or  taxes  that may be  assessed
against the property as a result of Lessee's usage of Premises.

34. Hazardous Materials

34.l DEFINITION

The term  "Hazardous  Materials"  shall mean any substance,  material,  or waste
which is or becomes regulated by any local governmental authority,  the State of
California, or the United States Government , including, but not limited to, any
material or substance  which is (i) defined as a "hazardous  waste,"  "hazardous
material,"  "hazardous  substance,"  "extremely hazardous waste," or "restricted
hazardous  waste" under any provision of  California.  law, and (ii)  petroleum,
(iii) asbestos, (iv) polychlorinated  biphenyls, (v) radioactive materials, (vi)
designated as a "hazardous substance" pursuant to Section 311 of the Clean Water
Act, 33 U.S.C. #1251 et seq. (33 U.S.C. #1321) or listed pursuant to Section 307
of the Clean Water Act (33 U.S.C.  #1317),  (vii) defined as  "hazardous  waste"
pursuant to Section 1004 of the  Resource  Conservation  and  Recovery  Act, 42
U.S.C.  #6901 et seq.  (42 U.S.C.  #6903),  or (viii)  defined  as a  "hazardous
substance" pursuant to Section 101 of the Comprehensive  Environmental Response,
Compensation  and Liability  Act, 42 U.S.C.  #9601 et seq. (42 U.S.C.  #9601) or
which is otherwise prohibited by law.

34.2 LESSEE'S COVENANT REGARDING HAZARDOUS MATERIALS.

Lessee at its sole cost shall comply with all laws relating to the storage,  use
and disposal of Hazardous Materials.  Lessee shall be solely responsible for and
shall  defend,  indemnify  and hold  Lessor and its agents  harmless  from,  and
against all claims costs and  liabilities,  including  attorneys' fees and costs
arising out of or in connection  with Lessee's  storage,  use and/or disposal of
Hazardous Material. This indemnity shall include, without limitation:

      (a) any damage, liability, fine, penalty, punitive damages cost or expense
      advising from or out of any claim, action, suit or proceeding for personal
      injury  (including  sickness,  disease or death),  tangible or  intangible
      property damage,  compensation for lost wages, business income, profits or
      other economic loss,  damage to the natural  resources or the environment,
      nuisance,  pollution,  contamination,  leaks,  spills,  release  or  other
      adverse effect on the environment, and

      (b) the cost of any reclaimed or necessary repair, clean-up,  treatment or
      detoxification of the Premises,  and the preparation and implementation of
      any  closure,  disposal,  remedial  or  other  required  actions  with the
      Premises.

If the  presence of Hazardous  Materials on the Premises  caused or permitted by
Lessee results in a level of contamination  greater than the levels  established
by any governmental  agency having  jurisdiction over such  contamination,  then
Lessee  shall  promptly  take  any and all  actions  necessary  to clean up such
contamination  if  required  by law or as a  condition  to  the  issuance  of or
continuing  effectiveness of any governmental  approval which relates to the use
of the Premises.  At the expiration of the term,  Lessee shall have the right to
conduct appropriate tests of water and soil to demonstrate that no contamination
in excess of  permitted  levels has  occurred as a result of Lessee's use of the
Premises. Lessee shall promptly deliver to the Lessor the results of such tests.
Lessee's obligations hereunder shall survive the termination of the Lease.





                                  AMENDMENT #1

This  amendment  shall  modify that certain  lease dated  October 6, 1987 by and
between Carl E. Berg and Mary Ann Berg,  Trustees of the Berg Living Trust,  UTA
dated May 1, 1981, as to an undivided 81.01% interest,  Clyde Berg & Nancy Berg,
Trustees  of the  Clyde  Berg  Living  Trust UTA dated  Dec.  17,  1981 as to an
undivided  11.83% and Clyde Berg,  Trustee of Carl Berg Child's  Trust UTA dated
June 2, 1978, as to an undivided 7.16% interest herein  collectively  Lessor and
APPLE COMPUTER, INC., herein Lessee.

The subject lease is hereby amended in the following particular:

ARTICLE #31 is amended and replaced as follows:

Damage or  Destruction.  If during the term of this lease the building or tenant
improvements  constructed  on the  leased  premises  are  totally  or  partially
destroyed from any cause, insured or uninsured, there shall be no abatement rent
whatsoever,  to the extent that from the rental abatement insurance described in
Article 6 are available and the Lessee shall be responsible at its sole cost and
expense to repair and restore such total or partial  damage or  destruction  and
restore  the  building  and  tenant   improvements  to  the  condition  existing
immediately  before  the  damage  and  destruction  as soon as it is  reasonably
possible to do so.

Except as herein  above  expressly  provided,  said Lease dated  October 6, 1987
shall remain unchanged. Consented to by the undersigned on

LESSOR

/s/ Carl E. Berg
CARL E. BERG

/s/ Mary Ann Berg by Carl E. Berg her Attorney in Fact
MARY ANN BERG

/s/ Clyde Berg
CLYDE BERG

/s/ Nancy Berg by Clyde Berg her attorney in Fact
NANCY BERG

/s/ Clyde Berg
CLYDE BERG, TRUSTEE

LESSEE
APPLE COMPUTER, INC.

By: /s/ Robert Hecex
Title: Manager Real Estate





                         SUMMARY OF SUBLEASE PROVISIONS


                                
Sublessor:                         McDonnell Douglas Corporation

Sublessee:                         Apple Computer, Inc.

Address of Premises:               20605, 20665 and 20705 Valley Green Drive
                                   Cupertino, CA

Square Footage of the Premises:    approximately 142,000 square feet

Term:                              One hundred twenty-two (122) months,
                                   subject to extension as provided in
                                   Paragraph 4.2 (Paragraph 4).

Commencement Date:                 November 1, 1987.

Rent:

Rent Commencement Date:            November 1, 1987.
Payment to:                        Regional Manager, Management Services
                                   Southern Pacific Industrial Development
                                   Company
                                   File #31461
                                   P.O. Box 6000
                                   San Francisco, CA 94160 (Paragraph 5).

Notices:

To Sublessor:                      Southern Pacific Industrial
                                   Development Company
                                   201 Mission St., Ste. 250
                                   San Francisco, CA 94105
                                   Attn: Regional Manager,
                                   Property Management Services

To Sublessee:                      Apple Computer, Inc.
                                   20525 Mariani Avenue
                                   Cupertino, CA 95014
                                   Attn: R.E. Department, MS 16-0

Copy to:                           Apple Computer, Inc.
                                   10201 DeAnza Blvd.
                                   Cupertino, CA 95014
                                   Attn: General Counsel
                                   (Paragraph 9).

Exhibits:                          Exhibit A - Master Lease.
                                   Exhibit B - Memorandum of Lease


Summary:
The foregoing  Summary of Sublease Terms is  incorporated  in and made a part of
the  Sublease to which such Summary of Sublease  Terms is attached.  If there is
any  conflict  between  such Summary of Sublease  Terms and such  Sublease,  the
latter shall control.





                                TABLE OF CONTENTS



                                                                 Page
                                                            
1.    Parties.....................................................1

2.    Subordination; Defaults; Provisions Constituting Sublease...1
      2.1  Subordination; Default under Master Lease..............1
      2.2  Provisions Constituting Sublease.......................2

3.    Premises....................................................3
      3.1  Subleased Premises.....................................3
      3.2  As Is..................................................3
      3.3  Sublessor's Warranty...................................4
      3.4  Alterations by Sublessee...............................4

4.    Term .......................................................5
      4.1  Sublease Term..........................................5
      4.2  Option to Extend Sublease Term.........................6
      4.3  Holding Over...........................................7

5.    Rent .......................................................7
      5.1  Rent...................................................7
      5.2  Rent During Extended Term..............................7
           (a) Mutual Agreement...................................8
           (b) Appraisal..........................................8
      5.3  Late Charge............................................9
      5.4  Charges................................................9

6.    Taxes.......................................................9
      6.1  Payment of Taxes.......................................9
      6.2  Substitute Taxes......................................10

7.    Maintenance of Premises....................................11

8.    Use  ......................................................11

9.    Notices......................................................
11
      9.1  General...............................................11
11
      9.2  Notices from Lessor...................................12

10.   Interest.....................................................
12

11.   Damage and Destruction.....................................12

12.   Condemnation...............................................13

13.   Insurance..................................................13

14.   Lessor's and Sublessor's Consent...........................14

15.   Assignment and Subletting..................................14
      15.1 Prohibitions in General...............................14
           (a) Transfer..........................................14
           (b) Hypothecation.....................................15
      15.2 Transfer Agreement....................................15
      15.3 Request for Transfer..................................16
      15.4 Excess Rents .........................................16
      15.5 Sublessor's Rights....................................17
15.6  Corporations and Partnerships..............................17
15.7  Reasonable Provisions......................................18
      15.8 Subject to Master Lease...............................18
      15.9 Miscellaneous.........................................18

16.   Default and Remedies.......................................18
      16.1 Events of Default.....................................18
      16.2 Remedies..............................................20
           16.2.1 Termination....................................20
           16.2.2 Continuance of Sublease........................21
           16.2.3 Reletting Premises.............................21
      16.3 Attorneys' Fees.......................................22
      16.4 Sublessor's Default...................................22
           16.4.1 Default........................................22
           16.4.2 Sublessee's Right to Perform Sublessor's
           Obligations Under the Master Lease....................22

17.   Quiet Enjoyment............................................23

18.   Right of Entry.............................................23

19.   Sublessor's Right to Perform Sublessee's Covenants.........23

20.   Surrender of Premises......................................24

21.   Option to Purchase.........................................24
      (a)  Notice................................................24
      (b)  Automatic Termination.................................24
      (c)  Sublessor to Exercise Option to Purchase..............24
      (d)  Terms of Sale.........................................25
           (i) Purchase Price....................................25
           (ii) Payment of Purchase Price........................25
           (iii) Close of Escrow.................................25
           (iv) Closing Costs....................................26
           (v) Condition of Title................................26
      (e)  No Warranties.........................................26
      (f)  Time..................................................26
      (g)  Right to Exchange.....................................26
      (h)  Notice Binding........................................26
      (i)  Limitation of Obligations of Sublessor;
           Indemnification.......................................27

22.   Right of First Refusal.....................................27
      22.1 Sublessee's Right to Exercise Right of First Refusal..27
      22.2 Attorney-in-Fact......................................28
      22.3 Terms of Sale.........................................28
           (a) Purchase Price....................................29
           (b) Payment of Purchase Price.........................29
           (c) Close of Escrow...................................30
           (d) Closing Costs.....................................30
      22.4 Limitations on Sublessor's Obligations;
           Indemnification.......................................30

23.   Property Loss; Damage......................................30
      23.1 Waiver of Claims......................................30
      23.2 Waiver of Subrogation.................................31
      23.3 Indemnification.......................................31

24.   General......................................................
31    24.1 Captions and Headings.................................31
24.2  Surrender of Sublease Not Merger...........................32
24.3  Interpretation of Terms....................................32
24.4  Counterparts...............................................32
24.5  Time of Essence............................................32
24.6  Severability...............................................32
24.7  Governing Law..............................................32
      24.8 Joint and Several Liability...........................32
      24.9 Construction of Sublease Provisions...................32
      24.10 Sublessor or Sublessee as Party Defendant............33
      24.11 Sublessor Not a Trustee..............................33
      24.12 No Partnership or Joint Venture......................33
      24.13 Exhibits.............................................33
      24.14 Attorneys' Fees......................................33
      24.15 Indemnities to Survive Sublease......................33
      24.16 Attorney-in-Fact.....................................33

25.   Entire Agreement...........................................33

26.   Real Estate Brokers........................................34

27.   Subordination..............................................34

28.   Hazardous Materials........................................34
      28.1 Definitions...........................................34
      28.2 Use of Premises and Compliance with Laws..............35
      28.3 Notice................................................35
      28.4 Indemnification.......................................36
      28.5 Charges...............................................36
      28.6 Liens.................................................36
      28.7 Sublessor's Right of Access...........................36
      28.8 Assignment and Subletting.............................37

29.   Memorandum of Sublease.....................................37

30.   Sublessor's Undertaking with Respect to Master Lease.......37

31    Covenant of Good Faith and Fair Dealing....................37

32.   Sublessor's Agent..........................................37






                                    SUBLEASE
1. Parties.  This Sublease ("Sublease") is entered into by and between McDONNELL
DOUGLAS CORPORATION, a Maryland corporation  ("Sublessor"),  and APPLE COMPUTER,
INC., a California corporation  ("Sublessee"),  as a sublease under that certain
Lease  ("Lease")  dated  January 6, 1978,  as amended by that certain  letter of
clarification,  dated February 17, 1978; Amendment ("Amendment"),  dated January
30, 1979;  Amendment #2 ("Amendment #2"), dated March 17, 1979; and Amendment #3
("Amendment  #3"), dated July 1, 1987  (collectively  the "Master Lease") by and
between JOHN A.  SOBRATO and SUSAN R.  SOBRATO,  as to an  undivided  forty-five
percent (45%)  interest,  and CARL E. BERG and MARY ANN BERG, as to an undivided
forty-five  percent  (45%)  interest,  and ANN RUSSO as to a ten  percent  (10%)
interest, predecessor in interest of the current lessor thereunder, Carl E. Berg
and Mary Ann Berg, as trustees on behalf of the Berg Living Trust UTA, dated May
1, 1981, as to an undivided 81.01% interest, Clyde Berg and Nancy Berg, Trustees
of the Clyde Berg Living Trust, UTA, dated December 17, 1981, as to an undivided
11.83% interest,  and Clyde Berg,  Trustee of Carl Berg Child's Trust UTA, dated
June 2, 1978, as to an undivided 7.16% interest ("Lessor"),  and TYMSHARE, INC.,
predecessor in interest of Sublessor,  as lessee.  A copy of the Master Lease is
attached hereto as Exhibit "A" and made a part hereof,  subject to the terms and
conditions of this Sublease.

2. Subordination; Defaults: Provisions Constituting Sublease.

2.1  Subordination;  Default under Master Lease.  As between the parties to this
Sublease, this Sublease is subject and subordinate in all respects to the Master
Lease,  and to the matters to which the Master Lease is subject and  subordinate
in  accordance  with its terms,  and to those  amendments to the Master Lease or
supplemental  agreements  thereunder made between  Sublessor and Lessor which do
not adversely affect or diminish  Sublessee's  rights, or materially  enlarge or
alter Sublessee's obligations or duties under this Sublease. Sublessee covenants
and agrees to refrain from doing or causing to be done, or permitting  any party
under its control to act in a manner, (i) which would constitute a default under
the Master  Lease or cause the Master Lease or the rights of Sublessor as lessee
under the Master Lease to be cancelled, terminated, forfeited or surrendered, or
(ii) which would make Sublessor liable for any damages,  claims or penalty under
the Master  Lease.  Sublessor  shall use  reasonable  efforts to cause Lessor to
perform  its  obligations  under  the  Master  Lease;  provided,  however,  that
Sublessor  shall have no liability  of any nature  whatsoever  to Sublessee  and
Sublessee  shall have no  liability of any nature  whatsoever  to Sublessor as a
consequence of Lessor's failure or delay in performing its obligations under the
Master Lease, including without limitation,  Lessor Is breach of the covenant of
quiet  enjoyment  set  forth  in  Paragraph  10  of  the  Master  Lease  or  the
non-disturbance  provisions of Paragraph 19 of the Master Lease. If Lessor shall
be in default under the Master Lease in any of its  obligations  to Sublessor or
in any of its  obligations to Sublessee,  if any,  Sublessee  shall,  by written
notice to Sublessor,  specify any such default by Lessor,  and Sublessor  shall,
after receiving such notice, either (i) take

                               - 1 -





action for the enforcement of Sublessor's  rights against Lessor with respect to
such  default as described in this  Paragraph  2.1 above,  or (ii) cure any such
default to the extent permitted  pursuant to the provisions of the Master Lease.
Sublessee shall be entitled to participate  with Sublessor in the enforcement of
Sublessor's rights against Lessor (and in any recovery or relief obtained to the
extent the parties'  respective  rights or  interests  are affected or costs are
incurred).  One-half  (1/2) of all expenses  incurred by Sublessor in connection
with its efforts to cause  Lessor to perform said  obligations  shall be paid to
Sublessor by Sublessee upon demand, as Charges (defined in Paragraph 5.4 below).
If Sublessee wishes to pursue Lessor's failure to perform its obligations  under
the Master  Lease in addition  to  Sublessor's  reasonable  pursuit of the same,
then,  provided  such action  would not  constitute  a default  under the Master
Lease,  Sublessee shall have the right to take  enforcement or self-help  action
against  Lessor in its own name or in the name of Sublessor and at its sole cost
and expense and, for that purpose and only to such extent,  all of the rights of
Sublessor to enforce or perform the obligations of Lessor under the Master Lease
are  hereby  conferred  upon and for this  purpose  assigned  to  Sublessee  and
Sublessee  hereby is  subrogated  to such rights  (including  the benefit of any
recovery or relief).  Sublessee shall indemnify and hold Sublessor harmless from
and against all loss, cost, liability,  claims,  damages and expenses (including
without limitation reasonable attorneys' fees),  penalties and fines incurred in
connection with or arising from the taking of any such action by Sublessee.

Sublessee's  obligations  hereunder (including without limitation the obligation
of Sublessee to pay all Rent (defined in Paragraph 5.1 below) and Charges) shall
not be  impaired  nor shall the  performance  thereof be excused  because of any
failure or delay on Lessor's part in performing its obligations under the Master
Lease unless (i) such failure or delay results from Sublessor's being in default
under  the  Master  Lease and  Sublessor's  default  thereunder  is not due to a
default of  Sublessee  hereunder,  or (ii) such  failure or delay  results  from
Sublessor's willful misconduct.  Under no circumstances shall Sublessee have the
right to require  performance  by Sublessor of Lessor's  obligations.  Sublessor
shall have no right to terminate  the Master  Lease,  unless an Event of Default
(defined  in  Paragraph  16.1 below)  occurs  hereunder  or except as  otherwise
provided in this Sublease.  In the event of such a permitted  termination of the
Master Lease, this Sublease shall terminate concurrently therewith,  without any
liability of Sublessor to Sublessee.  2.2 Provisions  Constituting Sublease. All
of the terms and  conditions  contained  in the  Master  Lease are  incorporated
herein,  except for Paragraphs 1, 2, 3(a),  3(c),  3(d), 3(e), 8, 9, 10, 11, 12,
13, 14,  17,  18, 19, 20, 25, 28, 29, 30, and 31 of the Lease,  Article 2 of the
Amendment  and all of the  provisions of Amendment #2 and Amendment #3, as terms
and conditions of this Sublease  (with (i) each reference  therein to lessor and
lessee  to be  deemed  to refer to  Sublessor  and  Sublessee,  except  that all
references to 'Lessor" in Paragraph 5 of the Master Lease shall mean both Lessor
and  Sublessor and those  obligations  of Lessor set forth in Paragraph 6 of the
Master Lease shall remain the obligations of Lessor,  and (ii) each reference to
"Lease" to be deemed to refer to

                               - 2 -





Sublease) and along with all of the paragraphs  set out in this Sublease,  shall
be the complete terms and conditions of this Sublease.  The parties  acknowledge
that to the extent the  provisions  contained in Paragraphs 10, 14, 19 and 31 of
the Master Lease are covenants running with the land, such covenants shall inure
to the benefit of, and Sublessee shall derive the benefit from such  provisions,
notwithstanding  that such provisions are not  incorporated  into this Sublease.
The enforcement provisions of Paragraph 2.1 above shall apply if Lessor breaches
any of the covenants in Paragraphs 10, 14, 19 and 31 of the Master Lease.

3. Premises.

3.1 Subleased Premises.  Sublessor leases to Sublessee and Sublessee leases from
Sublessor the premises  described in Paragraph 1 of the Master Lease, as amended
by Article 1 of the Amendment ("Premises").

3.2 As Is. The parties acknowledge that Sublessee intends to remove the existing
interior improvements from the Premises and to install new interior improvements
in accordance  with conceptual  plans and explanatory  detail to be developed by
Sublessee ("Tenant  Improvements").  Sublessee shall use good faith,  reasonable
efforts to submit said conceptual  plans and explanatory  detail to Sublessor no
later than November 15, 1987 for Sublessor's and Lessor's approval in accordance
with  Paragraph 5 of the Master  Lease.  This Sublease is  conditioned  upon the
written  consent or approval of Sublessor  and Lessor having been obtained on or
before  December 15, 1987 to the  conceptual  plans and  explanatory  detail for
Tenant Improvements,  in addition to Lessor's and Sublessor's concurrent consent
to  allowing  substantially  all of the  Tenant  Improvements  to  remain in the
Premises upon  surrender of the Premises by Sublessee and by Sublessor.  If, for
any reason,  Lessor's consent to the conceptual plans and explanatory  detail is
not obtained on or before  December 15, 1987,  either party may  terminate  this
Sublease;  provided,  however, that Sublessee shall nevertheless be obligated to
pay Rent and Charges through the later to occur of (i) December 31, 1987 or (ii)
the date the Premises are surrendered to Sublessor.

Sublessee  agrees to accept  the  Premises  and  appurtenances  thereto in their
existing "As Is" condition as of the Effective Date (defined  immediately  above
the  signatures  of the  parties),  subject  to the  limitations  set  forth  in
Paragraph 3.3 below.  Sublessor  acknowledges  that Sublessee has no interest in
subleasing  the  Premises  if  Sublessee  is unable to remodel  the  Premises to
accommodate  Sublessee's  intended use.  Accordingly,  Sublessee  shall have the
right to terminate  this Sublease by delivery of written notice to Sublessor (i)
on or before November 20, 1987 if Sublessee  determines that Hazardous Materials
(defined in Paragraph  28.1 below) are  discovered in the Premises or (ii) on or
before December 1, 1987 if Sublessee  reasonably  believes that  notwithstanding
good  faith  efforts  it will be  unable  to obtain a  building  permit  for the
remodeling  of the  Premises b;  February  15,  1988.  Subject to the  foregoing
conditions,  by taking  possession  of the  Premises  on the  Commencement  Date
(defined in Paragraph 4.1 below), Sublessee shall be deemed to have accepted the
Premises as being in good and sanitary  order,  condition and repair and to have
accepted the Premises in

                               - 3 -





their  condition  existing  as of the date  Sublessee  takes  possession  of the
Premises, subject to all applicable laws, covenants,  conditions,  restrictions,
easements and other matters of public record. Sublessee acknowledges that (i) it
has conducted all investigations, tests and studies concerning the Premises that
Sublessee  deems  appropriate  and  material to its  decision  to  sublease  the
Premises,  including  tests  and  investigations  concerning  the  existence  of
Hazardous Materials in and about the Premises; and (ii) that it has no knowledge
of the presence of any Hazardous Materials on the Premises,  except as otherwise
disclosed by Sublessee to  Sublessor  in writing.  Sublessee  acknowledges  that
except as provided in Paragraph 3.3,  neither  Sublessor nor Sublessor's  agents
have made any  representation  or warranty as to the suitability of the Premises
for the conduct of Sublessee's  business,  the condition of the Premises, or the
use or occupancy which may be made and Sublessee has independently  investigated
and is satisfied that the Premises are suitable for Sublessee's intended use and
that the Premises meet all governmental requirements for such intended use.

On the Commencement  Date,  Sublessor shall deliver  exclusive  occupancy of the
Premises to Sublessee free of all personal property and trade fixtures belonging
to Sublessor.

3.3 Sublessor's Warranty. Sublessor represents,  warrants and covenants that the
Premises and  everything  contained  therein for which  Sublessor is responsible
pursuant to the terms and  conditions  of the Master  Lease,  including  but not
limited to all equipment,  systems and other  component  parts thereof,  were in
good and clean  condition  and repair,  reasonable  wear and tear  excepted,  on
September  24,  1987.   Sublessor  further   represents  and  warrants  that  to
Sublessor's  knowledge  the  portion  of the  Premises  for which the  Lessor is
responsible pursuant to the terms and conditions of the Master Lease are in good
and  clean  condition  and  repair,  reasonable  wear and tear  excepted  on the
Effective  Date. To Sublessor's  knowledge,  Sublessor has provided to Sublessee
all information,  data,  documents,  plans,  specifications  and other materials
within the  possession,  or under the control of,  Sublessor  regarding  (i) the
existence  of  Hazardous  Materials,  if any, on the  Premises,  and (ii) to the
extent that Sublessee has requested such  information in writing,  the Premises,
its  design  and  physical  condition,  its  compliance  with  applicable  laws,
ordinances,  rules and regulations,  and other material matters,  and all of the
material  provided  to  Sublessor  in  accordance  with the  foregoing  has been
complete,  true and  correct  originals,  or copies  thereof.  As to the  future
condition of the Premises,  Sublessor  shall assign to Sublessee any  warranties
Sublessor  holds with respect to the Premises,  including,  without  limitation,
warranties for any equipment, systems and other component parts thereof.

3.4  Alterations by Sublessee.  Pursuant to Paragraph 5 of the Master Lease,  as
incorporated  into this  Sublease,  Lessor and  Sublessor  may  condition  their
consent to the making of any  alterations,  improvements or modifications to the
Premises upon Sublessee's agreement to remove the same upon its surrender of the
Premises.  Following Sublessor s receipt of Sublessee's plans and specifications
for  the  making  of  any  alterations,  improvements  or  modifications  to the
Premises,  Sublessor  shall  submit the same to Lessor for its  consent  and use
reasonable efforts to obtain Lessor's consent

                               - 4 -





and  concurrently  obtain  Lessor's  decision  as  to  whether  the  alteration,
improvement  or  modification  must be removed  upon  termination  of the Master
Lease.  If Sublessor  consents to any alteration,  improvement or  modification,
Sublessor  shall  advise  Sublessee  as to whether  Sublessor  may  require  the
alteration,  improvement  or  modification  to be removed from the Premises upon
termination  of the Sublease  Term.  If  Sublessor  advises  Sublessee  that any
alteration,  improvement  or  modification  may  remain  in  the  Premises  upon
termination of the Sublease Term,  Sublessor shall be bound by such decision and
may not thereafter revoke or change such decision. All alterations, improvements
or modifications made to the Premises by Sublessee, including without limitation
the Tenant  Improvements,  shall  remain the  property of  Sublessee  during the
Sublease Term, but those improvements which are to remain at surrender shall not
be altered or removed  from the Premises  prior to the end of the Sublease  Term
(except on compliance with the provisions of this  Sublease),  and at the end of
the Sublease Term, shall become  Sublessor's  property  without  compensation to
Sublessee by Sublessor or be removed by Sublessee in  accordance  with the terms
of Paragraph 20 below.

4. Term.

4.1 Sublease  Term. The term of this Sublease  ("Sublease  Term") shall be for a
period of one hundred twenty-two (122) months,  subject to extension pursuant to
the terms of Paragraph 4.2 below,  commencing on November 1, 1987 ("Commencement
Date") and ending on December 31, 1997.

With respect to the initial Sublease Term, Sublessee  acknowledges that pursuant
to  Paragraph  2 of the Master  Lease,  the  initial  term of the  Master  Lease
terminates on December 31, 1992. Thereafter,  Sublessor has the right and option
under said Paragraph 2 to renew the Master Lease for three (3)  additional  five
(5) year terms  commencing  automatically as of the expiration of the initial or
any extended term,  upon giving Lessor written notice of exercise of Sublessor's
option to renew at least one hundred  eighty (180) days prior to the  expiration
of the initial or any  extended  term.  Subject to all other  provisions  of the
Master  Lease which may cause the early  termination  of the Master Lease (other
than as a result of  Sublessor's  default  thereunder or a surrender  thereof by
Sublessor),  Sublessor  shall,  no later  than May 1, 1992,  exercise  its first
option to extend the Master Lease term to December 31, 1997.  Sublessor appoints
Sublessee as its special  attorney-in-fact  solely for the purpose of exercising
Sublessor's  first  option to extend the Master Lease term to December 31, 1997,
and  Sublessee  shall have the  nonexclusive  right to  exercise  such option in
Sublessor's  name,  if and only if  Sublessor  has not provided  Sublessee  with
written  evidence  of its  exercise  of  said  first  option  by  May  1,  1992.
Accordingly,  Sublessor shall not be liable to Sublessee for Sublessor's failure
to exercise  said  option.  Each party shall  deliver to the other a copy of its
exercise  notice  concurrently  with its  delivery  of the same to  Lessor.  The
foregoing  notwithstanding,  if an Event of  Default  exists at any time  either
party  desires or is required ;c exercise  the first option to extend the Master
Lease 'term to December 31, 1997, then at sum time Sublessor shall not obligated
to exercise  its first  option to extend the Master  Lease term for  Sublessee's
benefit  nor  shall  Sublessee  have  any  right  to  exercise  said  option  in
Sublessor's name as

                               - 5 -





special  attorney-in-fact  for Sublessor.  If, for any reason,  the Master Lease
term is not extended (other than due to the refusal of Lessor to honor or accept
the  exercise of the option to extend the Master  Lease,  except where due to an
Event of Default), then this Sublease shall terminate on December 31, 1992.

4.2 Option to Extend  Sublease  Term.  Sublessor  hereby grants to Sublessee the
option to extend the Sublease Term for two (2)  consecutive  five (5) year terms
(the "First Extended Term" and the "Second Extended Term," respectively, or each
an "Extended Term"), on the following terms and conditions;

(a)  Sublessee  shall give  Sublessor's  Agent  (defined in Paragraph 5.1 below)
written  notice of its  exercise  of the option to extend the  Sublease  Term no
earlier  than twelve (12) months nor later than nine (9) months  before the date
the initial Sublease Term ends (i.e., April 1, 1997), or the First Extended Term
ends (i.e., April 1, 2002), as the case may be. Time is of the essence.  Subject
to all of the  provisions  of  the  Master  Lease  which  may  cause  the  early
termination of the Master Lease (other than as a result of  Sublessor's  default
thereunder or surrender  thereof by Sublessor),  Sublessor  shall, no later than
May 1,  1997,  or no later than May 1, 2002,  as the case may be,  exercise  its
option to extend the Master Lease term to December 31, 2002,  or to December 31,
2007,  as  the  case  may  be.  Sublessor  appoints  Sublessee  as  its  special
attorney-in-fact  solely for the purpose of exercising the corresponding options
to extend the Master Lease term and Sublessee shall have the nonexclusive  right
to exercise such options in  Sublessor's  name, if and only if Sublessor has not
provided  Sublessee with written  evidence of its exercise of said options under
the Master Lease by May 1, 1997 or May 1, 2002, as the case may be. Accordingly,
Sublessor shall not be liable to Sublessee for  Sublessor's  failure to exercise
said  options.  Each party  shall  deliver  to the other a copy of its  exercise
notice concurrently with its delivery of the same to Lessor.

(b) The foregoing notwithstanding, if an Event of Default exists (i) at any time
Sublessee  exercises its option to extend the Sublease Term for either  Extended
Term,  or (ii) at any time either  party  desires or is required to exercise the
option to extend the Master  Lease Term to December  31,  2002 or  December  31,
2007,  as the  case may be,  then  Sublessee  may not at such  time  extend  the
Sublease  Term pursuant to this  Paragraph  4.2, nor shall,  Sublessee  have any
right,  at such time,  to exercise said  corresponding  options under the Master
Lease in Sublessor's name, as Sublessor's special attorney-in-fact.

(c) All terms and  conditions of this Sublease  shall apply during each Extended
Term,  except  that the Rent  for the  Extended  Term  shall  be  determined  in
accordance with Paragraph 5.2.

(d) Once Sublessee  delivers  notice of its exercise of the option to extend the
Sublease  Term,  Sublessee may not withdraw  such  exercise and,  subject to the
provisions  of this  Paragraph  4.2,  such  notice  shall  operate to extend the
Sublease  Term.  Upon  the  extension  of the  Sublease  Term  pursuant  to this
Paragraph 4.2, the term "Sublease Term" as used

                               - 6 -





in this  Sublease  shall  thereafter  include the Extended Term and the Sublease
termination  date shall be the expiration date of the Extended Term. 4.3 Holding
Over. If Sublessee remains in possession of the Premises after the expiration of
the Sublease Term, such tenancy shall be from  month-to-month only and shall not
be a renewal or an extension for any further term. In the event of such tenancy,
the monthly Rent due hereunder shall be one hundred  twenty-five  percent (125%)
of the Rent for the  month  preceding  the  Sublease  termination  and  shall be
payable at the times specified in Paragraph 5 below. Such month-to-month tenancy
shall  otherwise be subject to every  applicable  term,  covenant and  agreement
contained herein. Either party may terminate such tenancy upon thirty (30) day's
written notice of termination to the other.

5. Rent.

5.1 Rent.  Sublessee  shall pay to Sublessor  as monthly  rent  ("Rent") for the
Premises the following amounts:

                                  Monthly Rent
   


During the Period                                Installment  
                                                        
November 1, 1987 - December 31, 1987              $116,932    
January 1, 1988 - May 31, 1988                       -0-      
June 1, 1988 - October 31, 1992                   $116,932    
November 1, 1992 - December 31, 1997              $135,470    

    

Rent shall be payable in advance on the  Effective  Date and on the first day of
each calendar month thereafter and continuing throughout the Sublease Term. Rent
shall be prorated,  based on the number of days in the particular month, for any
partial month during the Sublease Term. Rent shall be payable without deduction,
offset,  prior  notice  or  demand  in  lawful  money of the  United  States  to
Sublessor's agent, Southern Pacific Industrial Development Company ("Sublessor's
Agent"),  to the attention of Regional Manager,  Property  Management  Services,
File #31461, at Post Office Box 6000, San Francisco,  CA 94160, or at such other
place or places as Sublessor or Sublessor's Agent may from time to time direct.

5.2 Rent During  Extended Term. If Sublessee  elects to extend the Sublease Term
pursuant to Paragraph  4.2, the annual Rent for each  Extended  Term shall be an
amount  equal to ninety  percent  (90%) of the fair market  rental  value of the
Premises in relation to market  conditions  at the time of the extension for the
uses of the Premises permitted under Paragraph 4 of the Master Lease (including,
but not limited to the following market conditions:  rental rates for comparable
space with comparable  tenant  improvements;  any adjustments to rent based upon
direct costs (operating  expenses) and taxes or rental adjustments;  the size of
the space;  lease  assumptions or  contributions;  the condition of the Premises
vis-a-vis  comparable  space;  leasing  commissions paid or payable;  methods of
determining escalations;  concessions,  if any, granted to tenants (such as free
rent,  moving  allowances,   etc.);  improvement  allowances  or  contributions;
building  standard  improvements;  and any other relevant  terms,  conditions or
factors which affect market rental values at the time of  extension);  provided,
that the Rent for each Extended Term shall in

                               - 7 -





no event be lower than the then existing  Rent.  The Rent for each Extended Term
shall be determined as follows:  (a) Mutual  Agreement.  After timely receipt by
Sublessor of Sublessee's notice of exercise of the option to extend the Sublease
Term,  Sublessor and Sublessee  shall have a period of thirty (30) days in which
to agree on the Rent for the First Extended Term or the Second Extended Term, as
the case may be. If  Sublessor  and  Sublessee  agree on said Rent  during  that
period, they shall immediately execute an amendment to this Sublease stating the
Rent for the applicable  Extended Term. If Sublessor and Sublessee are unable to
agree on the Rent for the applicable Extended Term as aforesaid,  the Provisions
of Paragraph 5.2(b) below shall apply.

(b) Appraisal.  Within five (5) days after the expiration of the thirty (30) day
period  described  in Paragraph  5.2(a)  above,  each party,  at its cost and by
giving notice to the other party, shall appoint an M.A.I. real estate appraiser,
with at least ten (10) years full-time  commercial appraisal experience and five
(5) years  full-time  commercial  appraisal  experience in the area in which the
Premises  are located,  to appraise and set the fair market  rental value of the
Premises.  If a party does not appoint an  appraiser  within five (5) days after
the other  party  has given  notice  of the name of its  appraiser,  the  single
appraiser  appointed  shall be the sole  appraiser and shall set the fair market
rental  value.  The cost of such sole  appraiser  shall be borne  equally by the
parties.  If two  appraisers  are  appointed  by the parties as provided in this
Paragraph 5.2(b),  the two appraisers shall meet promptly and attempt to set the
fair market  rental  value.  If they are unable to agree within twenty (20) days
after the last  appraiser  has been  appointed,  then the two  appraisers  shall
select a third  appraiser  meeting the  qualifications  stated in this Paragraph
5.2(b) within thirty (30) days after  appointment  of the second  appraiser.  If
they are unable to agree on the third appraiser  within the time period allowed,
either of the  parties to this  Sublease,  by giving ten (10) days notice to the
other party,  may apply to the  presiding  judge of the Superior  Court of Santa
Clara County for the selection of a third appraiser who meets the qualifications
stated  above.  Each of the  parties  shall bear  one-half  (1/2) of the cost of
appointing  the third  appraiser  and of paying the third  appraiser's  fee. The
third  appraiser,  however  selected,  shall be a person who has not  previously
acted in any  capacity  for  either  party.  Within  twenty  (20) days after the
selection of the third  appraiser,  the majority of the appraisers shall set the
fair market rental value.  If the majority of the  appraisers  are unable to set
the fair market  rental  value  within  said  twenty (20) day period,  the three
appraisals shall be added together and the total divided by three; the resulting
quotient shall be the fair market rental value and shall be deemed  incorporated
herein.  Provided,  however,  that if any  appraisal  differs  from  the  median
appraisal  by an amount  equal to more than ten  percent  (logo) of such  median
appraisal, that appraisal shall be disregarded, and the average of the remaining
appraisals (or the remaining  appraisal)  shall be the fair market rental value.
The terms of this Paragraph 5.2 shall control the  definition and  determination
of "fair market rental value" and the procedure used to make such  determination
and  the  jurisdiction  of  the  appraisers  is so  limited.  Any  determination
hereunder

                               - 8 -





shall be binding on the parties  absent  fraud or gross error and may be entered
as a judgment in court.  The  appraisers  shall have no right to alter,  vary or
amend  the  provisions  of this  Paragraph  5.2 in  making  their  determination
hereunder.  Either party may submit  evidence to the  appraisers  as to the fair
market  rental  value of the  Premises so long as each party  provides the other
party with a copy of the same to allow rebuttal evidence.  Evidentiary  hearings
shall not be held for purposes of  determining  fair market  rental  value.  The
determination of the appraisers, or each appraiser, if applicable,  shall be set
forth in detail,  in writing,  including  the  information  and data forming the
basis of the determination.

5.3 Late Charge. Sublessee hereby acknowledges that late payment by Sublessee to
Sublessor of Rent will cause  Sublessor to incur costs not  contemplated by this
Sublease,  the exact amount of which will be extremely  difficult to  ascertain.
Such costs include,  but are not limited to, processing and accounting  charges,
and late charges which may be imposed upon  Sublessor by the terms of the Master
Lease.  Accordingly,  Sublessee  shall pay to  Sublessor's  Agent,  as  Charges,
without the  necessity  of prior  notice or demand,  a late charge  equal to two
percent (2%) of any  installment  of Rent which is not  received by  Sublessor's
Agent  within  fifteen  (15) days after the due date for such  installment.  The
parties  hereby  agree that such late charge  represents  a fair and  reasonable
estimate  of the  costs  Sublessor  will  incur by  reason  of late  payment  by
Sublessee. In no event shall this provision for a late charge be deemed to grant
to  Sublessee  a grace  period  or  extension  of time  within  which to pay any
installment  of Rent or prevent  Sublessor  from  exercising any right or remedy
available to Sublessor upon Sublessee's  failure to pay such installment of Rent
when due, including without  limitation the right to terminate the Sublease.  In
the event any  installment of Rent is not received by  Sublessor's  Agent by the
thirtieth (30th) day after the due date for such  installment,  such installment
shall  bear  interest  at an  annual  rate set  forth  in  Paragraph  10  below,
commencing  on  the  thirty-first  (31st)  day  after  the  due  date  for  such
installment and continuing  until such installment is paid in full. In addition,
Sublessee  shall  pay all  reasonable  costs and  attorneys'  fees  incurred  by
Sublessor in the collection of such amounts.

5.4 Charges.  Sublessee shall timely pay all taxes, charges,  costs and expenses
and other sums which  Sublessee is required to pay hereunder  (together with all
interest and charges that may accrue thereon in the event of Sublessee's failure
to pay the same), and all damages,  costs and expenses which Sublessor may incur
by reason of any default by Sublessee (collectively,  "Charges"). The obligation
to pay Rent and Charges shall commence on the Commencement Date. In the event of
nonpayment  by Sublessee of any  Charges,  Sublessor  shall have all of the same
rights and remedies with respect  thereto as Sublessor has for the nonpayment of
Rent, including,  without limitation, the rights and remedies available pursuant
to  California  Civil Code  Sections 1941.2 and  1941.4,  or any  successor  or
replacement statute.

6. Taxes.

6.1 Payment of Taxes. At least twenty (20) days prior to delinquency,  Sublessee
shall pay any and all taxes,

                               - 9 -





assessments  or other charges  (other than those  charges  assessed by reason of
Sublessor's  default under the Master Lease to the extent not caused by an Event
of Default)  (i) payable by  Sublessor  pursuant  to the Master  Lease,  or (ii)
payable by Sublessor as owner of the Premises if and when Sublessor acquires fee
title to the same.  Sublessor will advise  Sublessee and provide  Sublessee with
copies of all  notices,  levies  and  assessments  of taxes  and  other  charges
respecting the Premises after  receiving  notification  from Lessor of the same.
Sublessor  shall use  reasonable  efforts  to arrange  for any and all  notices,
levies  and  assessments  of taxes  and other  charges  to be sent  directly  to
Sublessee.  If any notices, levies and/or assessments of taxes and other charges
are  delivered  directly to  Sublessee  or the  Premises  by any tax  authority,
Sublessee  shall  notify  Sublessor  of the  same  and  shall  pay  such  taxes,
assessments or charges  directly to the taxing  authority twenty (20) days prior
to delinquency  and provide  Sublessor with written  evidence of such payment at
least  twenty (20) days prior to  delinquency.  If any  notices,  levies  and/or
assessments  of taxes and other  charges are  delivered  to  Sublessee by either
Lessor or Sublessor,  Sublessee shall pay such taxes,  assessments or charges to
Lessor or  Sublessor,  as the case may be, at least  twenty  (20) days  prior to
delinquency.  To the extent permitted by the Master Lease or if Lessor otherwise
consents  thereto,   Sublessee's  payment  of  taxes  and  assessments  may,  at
Sublessee's  election, be paid in installments as may be permitted by law or the
taxing authority.

Pursuant  to  Paragraph  3(b) of the Master  Lease,  Sublessor  has the right to
contest in the name of Lessor,  or in its own name,  any tax, levy or assessment
which Sublessor is required to pay thereunder, in whole or in part. If Sublessee
wishes to contest the payment of any tax,  levy or  assessment,  then  Sublessee
shall  have the right to  contest  the same in the name of Lessor (to the extent
permitted by the Master  Lease),  in the name of Sublessor,  or in its own name.
Sublessor shall execute all documents necessary or appropriate to effectuate the
contest  and will use  reasonable  efforts to cause  Lessor to do the same.  Any
steps, actions or proceedings instituted by Sublessee shall be at the expense of
Sublessee.  Sublessee  shall  indemnify  and hold  Sublessor  harmless  from and
against all loss,  cost,  liability,  claims,  damages and  expenses  (including
without limitation reasonable attorneys' fees),  penalties and fines incurred in
connection with or arising from the taking of any such action by Sublessee.

6.2  Substitute  Taxes.   Should  the  State  of  California  or  any  political
subdivision  thereof  (including the County of Santa Clara or City of Cupertino)
levy or impose a tax,  assessment,  license fee or other  charge upon the Master
Lease,  this Sublease,  the estate created by the Master Lease or this Sublease,
or upon Lessor (or  Sublessor) by reason of its ownership of the fee interest in
the Premises,  or upon the rents or other income of the Lessor or Sublessor from
the Premises. and such tax, assessment, license fee or other charge is assessed,
in whole or in part, in lieu of property  taxes anchor  assessments  pursuant to
Paragraph  3(e) of the Master Lease,  there shall be an equitable  allocation of
such tax between Lessor and Sublessor, based upon the extent to which Lessor can
reasonably  establish  that such new tax is a substitute for real property taxes
assessed against the Premises for the fiscal period next preceding  enactment of
the

                              - 10 -





new tax.  Sublessor  and  Sublessee  shall meet and confer in order to determine
what the parties  believe to be an equitable  allocation  of such tax as between
Lessor and Sublessor. Sublessor shall present such determination to Lessor as an
appropriate  equitable  allocation.  The portion so  allocated  to  Sublessor by
Lessor shall be passed on to Sublessee accordingly.

7. Maintenance of Premises.  Sublessor shall not be responsible to Sublessee for
furnishing  any  service,  maintenance  or  repairs to the  Premises,  including
without  limitation all structural  and  nonstructural  portions of the roof, it
being  understood  that such  obligations,  if any,  are either  those of Lessor
pursuant to the Master Lease or those of Sublessee,  pursuant to this  Sublease.
The  foregoing  notwithstanding,  if  any  dispute  arises  between  Lessor  and
Sublessor  regarding  the  obligation  to  maintain  and repair  the  structural
portions of the Premises "including without limitation concrete walls, footings,
concrete slab or roof structure), or Lessor fails to maintain or repair the same
after the enforcement  provisions of Paragraph 2.1 above have been  effectuated,
Sublessor shall perform the required  maintenance or repair (except with respect
to the roof, which maintenance and repair obligations Sublessee shall perform at
its sole  cost  and  expense),  at its sole  cost  and  expense.  The  foregoing
notwithstanding,  Sublessee shall maintain and repair all structural portions of
the  Premises  which have been  constructed,  altered,  modified  or improved by
Sublessee if, and to the extent, any such construction, alteration, modification
or  improvement  would  give rise to a  defense  by  Lessor  to its  repair  and
maintenance obligations under the Master Lease.

8. Use.  Sublessee  shall be entitled to use the Premises for any uses permitted
under  Paragraph  4 of  the  Master  Lease  (but  not  for  underground  storage
facilities and only for aboveground storage facilities  reasonably necessary for
Sublessee's  use of the  Premises)  and for no other  purpose  without the prior
written  consent of Sublessor.  Sublessee  shall not do or suffer anything to be
done upon the Premises which will cause  structural  injury to the Premises.  If
any act on the part of  Sublessee  or use of the  Premises  by  Sublessee  shall
cause,  directly or indirectly,  any increase of Sublessor's  insurance  expense
under  the  Master  Lease,  if any,  said  additional  expense  shall be paid by
Sublessee to Sublessor upon demand.

9. Notices.

9.1  General.  Any notice  required or desired to be given  under this  Sublease
shall be in writing and all notices shall be given by personal  delivery or by a
commercial  courier service which  guarantees  overnight  delivery.  The parties
hereto  intend that the notice  requirements  contained in this  Sublease  shall
supersede those contained in the California Code of Civil Procedure Section 1161
and any successor or replaces, statute, and that any notice served in accordance
with the  requirements  hereof  shall be  sufficient  for the  purposes  of such
statutory  requirements.  All notices  delivered by courier shall be paid for by
the sender and  addressed to the  addresses set forth in the Summary of Sublease
Provisions. Either party may change its address for purposes of notice by giving
notice Of such change of address to the other

                              - 11 -





party in accordance with the provisions of this paragraph at least ten (10) days
before the  effective  date of the  change.  Any notice  given  pursuant to this
Paragraph 9.1 shall be deemed served when  delivered by personal  service,  with
delivery evidenced by a signed receipt, or the day of delivery by the commercial
courier service, as evidenced by its signed receipt.

9.2 Notices from Lessor. Sublessee shall send to Sublessor's Agent a copy of all
notices  and other  communications  it shall  receive  from  Lessor  (including,
without limitation,  any notices of default) which pertain to the Premises,  the
Master  Lease or this  Sublease  within  forty-eight  (48) hours of  receiving a
notice or other  communication.  Sublessor's  Agent (or Sublessor,  if Sublessor
receives  the  notice)  shall send to  Sublessee a copy of all notices and other
communications it shall receive from Lessor (including,  without limitation, any
notices of default)  which  pertain to the  Premises,  the Master  Lease or this
Sublease  within   forty-eight  (48)  hours  of  receiving  a  notice  or  other
communication.

10. Interest. Any payment due from one party to the other (except for Rent which
is addressed  below) shall bear  interest  from the date due until paid,  at the
rate of ten  percent  (10%) per annum.  Rent not  received by  Sublessor  within
thirty (30) days after the same is due shall bear interest from the thirty-first
(31st) day after the due date until paid,  at the rate of ten percent  (10%) per
annum.  Notwithstanding  the foregoing,  any  nonrecurring  payment due from one
party to the other, including, without limitation, payments due under Paragraphs
16.4.2  and 19 below,  shall  not bear  interest  until ten (10) days  following
delivery of written notice from one party to the other that said payment is due.
In  addition,  Sublessee  shall pay all  reasonable  costs and  attorneys'  fees
incurred by Sublessor in the collection of such amounts.

11. Damage and  Destruction.  Neither  Sublessor  nor  Sublessee  shall have any
obligation to rebuild, restore or repair all or a portion of the Premises in the
event of any damage or destruction  thereto,  but Sublessor shall use reasonable
efforts to cause Lessor to perform its obligation to do so pursuant to Paragraph
2.1 above.  If Lessor elects to terminate the Master Lease pursuant to the terms
and conditions of Paragraph 8 of the Master Lease, this Sublease shall terminate
concurrently  therewith  without any  liability of Sublessor  to  Sublessee.  If
Sublessor  is entitled to  terminate  the Master  Lease  pursuant to Paragraph 8
thereof,  then  Sublessee may elect to terminate this Sublease by written notice
delivered to Sublessor  within one hundred fifty (150) days from the destructive
event.

If Sublessor is entitled to terminate  the Master Lease  pursuant to Paragraph 8
thereof and Sublessor desires to so terminate the Master Lease,  Sublessor shall
provide  Sublessee  written  notice of  Sublessor's  intention to terminate  the
Master Lease  within one hundred  twenty  (120) days of the  destructive  event.
Sublessee  shall approve or disapprove  Sublessor's  intention by written notice
delivered to Sublessor  within one hundred  fifty (150) days of the  destructive
event.  If Sublessee  approves  Sublessor s intention  to  terminate  the Master
Lease, then Sublessor may notify Lessor of Sublessor's election to terminate the
Master Lease pursuant to

                              - 12 -





Paragraph 8 thereof and this  Sublease  shall  terminate  concurrently  with the
termination of the Master Lease.  If Sublessee  desires to continue the Sublease
and  disapproves  Sublessor's  intention to  terminate  the Master  Lease,  then
Sublessor  shall not terminate the Master Lease and the Sublease shall continue.
Except as  expressly  provided  herein,  Sublessee  waives  any other  rights to
terminate this Sublease, including without limitation any rights pursuant to the
provisions of Subdivision 2 of Section 1932 and Subdivision 4 of Section 1933 of
the  California  Civil Code, as amended from time to time, and the provisions of
any similar law hereinafter enacted,  which provisions relate to the termination
of the hiring of a thing upon its  substantial  damage and  destruction.  In the
event of any damage or destruction to the Premises,  the then-current Rent shall
be  proportionately  reduced in the same proportion and for the same period that
the rent paid by  Sublessor  to Lessor for the  Premises is reduced  pursuant to
Paragraph 8 of the Master Lease. All other amounts due pursuant to this Sublease
shall continue  unaffected or shall be abated in the same proportion and for the
same period that such amounts are abated to Sublessor pursuant to Paragraph 8 of
the Master Lease.

12.  Condemnation.  If any part of the Premises shall be taken for any public or
quasi-public  use,  under any  statute or by right of eminent  domain or private
purchase  in lieu  thereof,  this  Sublease  shall,  as to the  part  so  taken,
terminate  as of the date  title  shall  vest in or  possession  is taken by the
condemnor or  purchaser,  and the Rent payable  hereunder for the portion of the
Premises remaining shall be  proportionately  reduced according to the extent to
which such taking shall  interfere with or curtail  Sublessee's  business on the
Premises.  Provided  Sublessor has the right to terminate the Master Lease under
the conditions described in Paragraph 9 thereof,  Sublessee shall have the right
to terminate  this  Sublease by delivering  to Sublessor  written  notice of its
intention to terminate the Sublease  within ten (10) days  following the date of
said taking. For purposes of the foregoing, Sublessee's then business operations
in the Premises shall be deemed Sublessor's and Sublessee's  judgments regarding
the suitability of the Premises for its business  operations shall be binding on
Sublessor.  In such event,  this Sublease shall  terminate,  effective as of the
date of such  taking,  pursuant to  Paragraph 9 of the Master  Lease.  Any award
received by Sublessor or Sublessee as a result of the taking of all or a portion
of the  Premises  under any right of eminent  domain,  or any  transfer  in lieu
thereof,  shall  belong to  Sublessor,  however,  Sublessee  shall  receive from
Sublessor's  award or  portion of the award (i) the value of  Sublessee's  trade
fixtures,  equipment and other property  installed by it, moving expenses,  (ii)
seventy-five  percent  (75%) of the value,  if any, of  Sublessee's  interest or
subleasehold  estate,  if any, and (iii) other special  damages  provable in the
condemnation action.

13.  Insurance.  All  insurance  policies  required  to be carried by  Sublessee
pursuant o Paragraph  27 of the Master Lease shall name  Lessor,  Sublessor  and
Sublessor's  Agent  (with  respect to the  insurance  required  to be carried by
Sublessee  pursuant  to  Paragraph  27(b) of the  Master  Lease)  as  additional
insureds and shall provide that such policy or policies  shall not be subject to
cancellation or change except after at least

                              - 13 -





thirty  (30) days prior  written  notice to Lessor,  Sublessor  and  Sublessor's
Agent. 14. Lessor's and Sublessor's  Consent.  If Sublessor  approves any matter
requiring  Sublessor's  consent herein and such matter further requires Lessor's
approval under the Master Lease,  or if only Lessor's  consent is required under
the Master Lease,  Sublessor  shall promptly submit the same to Lessor and shall
use  Sublessor's  reasonable  efforts (with Sublessor and Sublessee each bearing
one-half (1/2) of the costs and expenses associated  therewith in the manner set
forth in Paragraph  2.1 above) to obtain  Lessor's  approval of such matter.  If
Sublessor  does not  consent to any matter as to which its  consent is  required
hereunder,  Sublessor shall advise Sublessee,  in writing, in reasonable detail,
of the basis for its decision.  Sublessor shall use reasonable efforts to obtain
similar information from Lessor,  where Lessor does not consent to any matter as
to which its consent is required  pursuant to the Master  Lease.  Any  approvals
required to be given by Sublessor to Sublessee  hereunder  (including  approvals
under Paragraph 15 below) shall not be unreasonably withheld or delayed, and, if
such  approval  or  disapproval  is not given  within  thirty (30) days (or such
longer or shorter time period as may  otherwise be permitted by this Sublease or
the Master Lease) following Sublessee's written request for the same, the matter
shall be deemed approved by Sublessor unless such approval would cause a default
under the Master Lease. In no event, however,  shall Sublessor's  disapproval be
deemed  unreasonable if (but only for so long as) Lessor has disapproved of such
matter (but Lessor's  disapproval  shall not be considered either evidence or an
admission of the reasonableness  thereof) nor shall Sublessor have any liability
to Sublessee by reason thereof, other than by reason of a breach by Sublessor of
its obligations under this Sublease.

15. Assignment and Subletting.

15.1 Prohibitions in General.

(a) Transfer.  Sublessee shall not (whether  voluntarily,  involuntarily,  or by
operation  of law) (i)  assign  this  Sublease  or allow  all or any part of the
Premises  to be sublet,  occupied,  or used by any  person or entity  other than
Sublessee, (ii) transfer any right appurtenant to this Sublease or the Premises,
or (iii)  permit any person to assume or succeed to any interest  whatsoever  in
this Sublease  (collectively,  "Transfer"),  without  Sublessor's  prior written
consent in each  instance,  which  consent shall not be  unreasonably  withheld,
subject, nevertheless, to the restrictions, limitations and conditions set forth
in this Paragraph 15. The foregoing  notwithstanding,  Sublessee may sublease up
to an aggregate of thirty thousand  (30,000) square feet of the Premises without
Sublessor's  prior  written  consent,  but  subject  to all other  restrictions,
limitations  and  conditions,  applicable  to  a  Transfer,  contained  in  this
Paragraph  15.  With  respect to (A)  subleases  for less than  thirty  thousand
(30,000) square feet of the Premises,  and (B) Affiliate  Transfers  (defined in
Paragraph 15.6 below),  Sublessee may nevertheless  request  Sublessor's consent
thereto  for  purposes  of  Paragraph  24.2(i),   which  consent  shall  not  be
unreasonably withheld. Any Transfer contrary to the provisions of this

                              - 14 -





Paragraph  15 shall  constitute  an Event of Default  and shall be  voidable  by
Sublessor,  except where such  Transfer is rescinded  within thirty (30) days of
Sublessor's  written  notice  to  Sublessee  of  Sublessor's  disapproval  of or
withholding of consent to such Transfer. Sublessor's consent to any one Transfer
shall not  constitute a waiver of the  provisions of this Paragraph 15 as to any
subsequent  Transfer  nor a  consent  to any  subsequent  Transfer.  Sublessor's
consent  to any one  Transfer  shall  not  release  Sublessee  from  Sublessee's
obligations under this Sublease.  Except as otherwise provided in this Paragraph
15, the  effectiveness  of a proposed  Transfer is conditioned  upon Sublessor's
written  consent to the same.  The  Transfer  shall be valid and the  Transferee
(defined  in  Paragraph  15.3)  shall have the right to take  possession  of the
Premises only if an executed  counterpart of the  assignment,  sublease or other
document  evidencing  the Transfer is delivered to Sublessor  and such  transfer
document is consistent  with the  information  set forth in  Sublessee's  notice
given to Sublessor  pursuant to Paragraph 15.3, or any modifications  thereto to
which Sublessor has a right to consent and has consented to in writing.

(b)  Hypothecation.  Notwithstanding  any  other  provision  of  this  Sublease,
Sublessee shall not (whether voluntarily, involuntarily, or by operation of law)
hypothecate,  mortgage  or encumber  as  security  Sublessee's  interest in this
Sublease  or in the  Premises  (or  otherwise  use the  Sublease  as a  security
device),  without  Sublessor's  prior written  consent in each  instance,  which
consent  may be  withheld  in  Sublessor's  sole and  absolute  discretion.  Any
hypothecation,  mortgage or encumbrance  (collectively  "Hypothecation") without
Sublessor's  consent shall  constitute a default by Sublessee and shall be void.
Sublessor's  consent to any one  Hypothecation  shall not constitute a waiver of
the  provisions of this Paragraph 15 as to any  subsequent  Hypothecation  nor a
consent to any  subsequent  Hypothecation.  All  Hypothecations  are  subject to
Paragraphs 15.7 through 15.9 below.

15.2 Transfer  Agreement.  As a condition to the  effectiveness of any Transfer,
the document evidencing the Transfer between Sublessee and Sublessee's assignee,
subsublessee,  or  transferee  (collectively,   "Transferee")  shall  include  a
provision that Sublessee's  Transferee  expressly  assumes those  obligations of
Sublessee  under this  Sublease so  delineated  in the document  evidencing  the
Transfer,  and shall be and remain  jointly and severally  liable with Sublessee
for the performance of those  obligations under this Sublease from the effective
date of the Transfer.  Sublessee  shall remain liable for the performance of all
conditions,  covenants, and obligations under this Sublease, whether or not such
conditions,  covenants,  and  obligations  have been  expressly  assumed  by the
Transferee.   As  a  condition  to  any  Hypothecation   (and  without  limiting
Sublessor's  right to withhold consent to any  Hypothecation in Sublessor's sole
discretion)  of  Sublessee's  interest  in this  Sublease or the  Premises,  the
document   evidencing  the  Hypothecation   between  Sublessee  and  Sublessee's
encumbrances,   hypothecatee  or  mortgagee  (collectively   "mortgagee")  shall
include- a provision  that when  Sublessee's  Mortgagee  succeeds to Sublessee's
interest through foreclosure or otherwise, Sublessee's Mortgagee shall expressly
assume all  obligations of Sublessee  under this Sublease,  other than uncurable
Events of Default,  shall be bound by all  Provisions of this Sublease and shall
be and

                              - 15 -





remain jointly and severally  liable with  Sublessee for the  performance of all
conditions,  covenants  and  obligations  under this Sublease from the date that
such  Mortgagee  succeeds  to  Sublessee's  interest  in  this  Sublease  or the
Premises.

15.3 Request for Transfer. Sublessee shall give Sublessor twenty (20) days prior
written notice of any desired Transfer, which notice shall include the following
information:  (i) the term or duration of such Transfer;  (ii) the nature of the
Transfer; (iii) the name and legal composition of the proposed Transferee;  (iv)
the allocation of  responsibilities  and obligations  between  Sublessee and the
proposed  Transferee;  (v) an audited financial statement prepared in accordance
with  generally  accepted  accounting   principles  (or  a  statement  providing
equivalent  information  and  evidencing  the  truth  and  completeness  of  the
information  contained  therein) of the proposed  Transferee dated as of a date,
and for the period  ending on such date,  which is within  fifteen  (15)  months
prior to the proposed  effective  date of the  Transfer;  (vi) the nature of the
proposed  Transferee's  business  to be carried on in the  Premises  (including,
without  limitation,  any proposed use of  Hazardous  Materials);  and (vii) the
payment  to be made  or  other  consideration  to be  given  on  account  of the
Transfer;  all in reasonably  sufficient  detail to enable Sublessor to evaluate
the proposed Transfer and the prospective  Transferee.  Sublessee's notice shall
not be deemed to have been  served or given  until  such time as  Sublessee  has
provided  Sublessor with all information  specified  above,  but Sublessor shall
promptly notify  Sublessee of any missing or incomplete  information.  Sublessee
shall  immediately  notify Sublessor of any modification to the foregoing items.
Sublessor's  consent to any Transfer for which  consent is required or requested
hereunder  shall be based on the financial  ability of the Transferee to perform
its obligations under the proposed Transfer (including,  but not limited to, the
obligations  set  forth  in  Paragraph  28 of this  Sublease)  and  whether  the
Transferee's proposed use is permitted by the Master Lease and this Sublease.

15.4 Excess Rents. Sublessor shall be entitled to one-fourth (1/4) of any Excess
Rents (defined  below)  payable by any  Transferee and Sublessee  shall pay such
amount to  Sublessor  as and when the same is  received by  Sublessee  following
recovery of the Costs (defined  below)  incurred by Sublessee in connection with
said Transfer. "Excess Rents" shall mean any and all rents, payments, charges or
other  consideration  received by Sublessee  from a Transferee  in excess of the
Rent and Charges payable by Sublessee to Sublessor  (calculated on a "per square
foot" basis if less than the entire  Premises  is the  subject of the  Transfer)
after recovery by Sublessee of the following  ("Costs"):  (a) all costs incurred
in  connection  with  the  Transfer,   including   attorneys'   fees,   brokers'
commissions,  allowances, concessions, the cost of constructing improvements and
the cost of Sublessee's  performance under any sub-sublease (if other than a net
lease), and (b) the unamortized cost of any improvements to or personal property
(to the extent included for purposes of calculating  "rent" under this Paragraph
15)  the  Premises  constructed  O.  paid  for by  Sublessee  (Sublessee  hereby
acknowledging  that the Tenant  Improvements  will be fully amortized during the
initial Sublease Term) in the portion of the Premises that is the subject of the
Transfer,  in each  case,  so long as the term of the  Transfer  is for the full
Sublease Term (including any

                              - 16 -





option to extend the Sublease Term which must be exercised by Sublessee pursuant
to Sublessee's agreement with the Transferee).  Otherwise,  Sublessee shall only
be entitled to recovery  of a pro rata  portion of the  unamortized  cost of its
improvements  amortized over the term of the Transfer.  For the purposes of this
Paragraph  15, the term  "rent"  shall  include  any  consideration  of any kind
received,  or to be received,  by Sublessee (or from any subtenant of Sublessee)
from the  Transferee,  if such sums are related to Sublessee's  interest in this
Sublease  or in the  Premises,  including,  but not  limited  to,  key money and
payments for Sublessee's  personal property in excess of the unamortized cost or
book value  thereof.  The term  "personal  property" as used in this  subsection
shall refer to fixtures, inventory, good will, equipment and furniture.

15.5 Sublessor's Rights. If Sublessee seeks to make any Transfer of its interest
in this  Sublease or the Premises,  Sublessor  shall have the right to condition
its consent to such  Transfer on the  requirement  that either  Sublessee or the
proposed  Transferee  cure,  on or before the  proposed  effective  date of such
Transfer, any and all uncured Events of Default; provided,  however, in no event
shall  Sublessor's  failure to condition its consent upon such cure be deemed to
be a waiver of any such  Event of  Default or  Sublessor's  rights and  remedies
under this Sublease or law in regard  thereto.  If the cure period for any Event
of Default has not expired by the date upon which  Sublessor  must  respond to a
request for consent to a Transfer in accordance with this Paragraph 15, then the
period within which  Sublessor  must respond shall be extended,  at  Sublessor's
option, to the date following the day on which the cure period for such existing
Event of Default expires. If Sublessor elects to impose such cure as a condition
to its consent and such  condition is not satisfied by the effective date of the
Transfer, the Transfer shall be voidable at Sublessor's option.

15.6 Corporations and Partnerships.  If Sublessee is a partnership, a withdrawal
or  substitution  (whether  voluntary,  involuntary  or by  operation of law and
whether  occurring  at one  time  or  over a  period  of  time)  of any  general
partner(s)  owning more than fifty  percent (50%) of any interest in the capital
or profits of the  partnership,  or the dissolution of the partnership  shall be
deemed a Transfer of this Sublease.  If Sublessee is a corporation,  the capital
stock of which is not publicly traded, any dissolution, merger, consolidation or
other reorganization of Sublessee,  any sale or transfer (or cumulative sales or
transfers) of the capital  stock of Sublessee in excess of fifty percent  (50%),
or any sale (or cumulative sales) of fifty-one percent (51%) of the value of the
assets of Sublessee shall be deemed a Transfer of this Sublease. Notwithstanding
the foregoing,  Sublessee may, without Sublessor's prior written consent.  enter
into any Transfer  with:  (i) a subsidiary,  affiliate,  division or corporation
controlled  by or under  common  control  with  Sublessee;  or (ii) a  successor
corporation  related  to  Sublessee  by  merger,  consolidation,  non-bankruptcy
reorganization,  or government action ("Affiliate Transfers"). Upon request from
Sublessee,  Sublessor  shall  execute  an  acknowledgement,  in form  reasonably
satisfactory to Sublessor,  evidencing that Sublessor's  consent is not required
for a Transfer meeting the criteria herein set forth.

                              - 17 -





15.7 Reasonable  Provisions.  Sublessee  expressly agrees that the provisions of
this Paragraph 15 are not  unreasonable  standards or conditions for purposes of
Section 1951.4(b)(2) of the California Civil Code, as amended from time to time.

15.8  Subject to Master  Lease.  Sublessee  acknowledges  that any  Transfer  or
Hypothecation  hereunder  is subject to the terms and  conditions  of the Master
Lease.

15.9   Miscellaneous.   Regardless  of  Sublessor's   consent,  no  Transfer  or
Hypothecation  shall release Sublessee of Sublessee's  obligations  hereunder or
alter the  primary  liability  of  Sublessee  to pay the Rent and Charges and to
perform all other  obligations  to be  performed  by  Sublessee  hereunder.  The
acceptance  of Rent or Charges by  Sublessor  from any other person shall not be
deemed to be a waiver by  Sublessor  of any  provision  hereof.  In the event of
default by any  Transferee,  Mortgagee  or any  successor  of  Sublessee  in the
performance of any of the terms hereof,  Sublessor may proceed  directly against
Sublessee without the necessity of exhausting  remedies against said Transferee,
Mortgagee  or  successor.  Sublessor  may  consent to  subsequent  Transfers  or
Hypothecations  of this Sublease or amendments or modifications to this Sublease
with any  Transferee,  Mortgagee or successor of  Sublessee,  without  notifying
Sublessee,  or any  successor of Sublessee,  and without  obtaining its or their
consent  thereto and such action shall not relieve  Sublessee of liability under
this  Sublease,  except that  Sublessee  shall not be bound by any  amendment or
modification to which Sublessee has not consented.

Sublessee acknowledges that Sublessor's right, in its reasonable discretion,  to
withhold consent to a proposed  Transfer  described in Paragraph  15.1(a)(ii) or
15.1(a)(iii)  and all other  provisions  of this  Paragraph 15 are  commercially
reasonable,  agreed-upon and bargained-for rights of Sublessor and that the Rent
and Charges set forth in the Sublease have taken into consideration  Sublessor's
rights under this Paragraph 15.

16. Default and Remedies.

16.1  Events of Default.  The term  "Event of Default" as used in this  Sublease
shall mean the occurrence of any of the following events:

(a) Sublessee's failure to pay when due any Rent or Charges,  where such failure
shall  continue for a period of ten (10) days after written  notice thereof from
Sublessor to Sublessee;

(b) Unless actively and diligently  contested.  by Sublessee,  commencement  and
continuation for at least sixty (60) days of any case,  action or proceeding by,
against  or  concerning   Sublessee  under  any  federal  or  state  bankruptcy,
insolvency or other debtor's relief law,  including  without  limitation,  (i) a
case under Title 11 of the United  States  Code  concerning  Sublessee,  whether
under Chapter 7, 11, or 13 of such Title or under any other  Chapter,  or (ii) a
case, action or proceeding seeking  Sublessee's  financial  reorganization or an
arrangement with any of Sublessee's creditors;

                              - 18 -





(c) Voluntary  appointment  of a receiver,  trustee,  keeper or other person who
takes  possession  for  more  than  sixty  (60)  days  of  substantially  all of
Sublessee's assets used in Sublessee's  business on the Premises,  regardless of
whether such appointment is as a result of insolvency or any other cause;

(d)  Unless  actively  and  diligently   contested  by  Sublessee,   involuntary
appointment of a receiver,  trustee, keeper or other person who takes possession
for more than sixty (60) days of substantially all of Sublessee's assets used in
Sublessee's business on the Premises,  regardless of whether such appointment is
as a result of insolvency or any other cause;

(e) Execution of an assignment for the benefit of creditors of substantially all
assets of Sublessee available by law for the satisfaction of judgment creditors;

(f) Commencement of proceedings for winding up or dissolving  (whether voluntary
or  involuntary)  the entity of Sublessee if  Sublessee  is a  corporation  or a
partnership, which proceedings are not dismissed within sixty (60) days;

(g) Levy of a writ of attachment or execution on Sublessee's interest under this
Sublease,  if such writ is not being  contested  and  continues  for a period of
sixty (60) days;

(h) Transfer or  Hypothecation  or attempted  Transfer or  Hypothecation of this
Sublease or the Premises by Sublessee contrary to the provisions of Paragraph 15
above,  except where such Transfer or  Hypothecation  is rescinded within thirty
(30) days of Sublessor's written notice to Sublessee of Sublessor's  disapproval
of or withholding of consent to such Transfer or Hypothecation;

(i) The  failure of  Sublessee  promptly to observe or perform any of the terms,
covenants, conditions,  warranties or other provisions contained in Paragraph 28
below,  where  Sublessee  fails to commence to cure within  seven (7) days after
written  notice  thereof from Sublessor and to complete the cure within a period
of thirty (30) days after said written notice from Sublessor; provided, however,
that if the nature of  Sublessee's  default is such that more than  thirty  (30)
days are reasonably  required for its cure, then no Event of Default shall exist
if Sublessee  commences to cure within said seven (7) day period and  thereafter
diligently prosecutes such cure to completion; or

(j) Breach by  Sublessee  of any other term,  covenant,  condition,  warranty or
other provision contained in this Sublease (which shall incorporate all exhibits
attached  hereto),  where such breach shall continue for a period of ninety (90)
days after written notice therefrom from Sublessor to Sublessee of the nature of
such default.

Any notice  given by Sublessor  to  Sublessee  pursuant to (a),  (h), (i) or (j)
above shall be delivered to both addresses of Sublessee set forth on the Summary
of Sublease Provisions (including the copy address) and if so delivered shall be
sufficient  notice for the purpose of California Code of Civil Procedure Section
1161, or any successor or

                              - 19 -





replacement  statute, if served in accordance with the requirements of Paragraph
9.1 above and no  additional  notice shall be required in order for Sublessor to
commence an unlawful detainer proceeding. Sublessor shall take such steps as are
reasonably  necessary  to  mitigate  any  damages  resulting  from a default  by
Sublessee.

16.2 Remedies. Upon any default by Sublessee, Sublessor shall have the following
remedies, in addition to all other rights and remedies provided by law, to which
Sublessor may resort cumulatively, or in the alternative:

16.2.1  Termination.  Upon any default by  Sublessee,  Sublessor  shall have the
right (but not the obligation) to terminate this Sublease and Sublessee's  right
to possession of the Premises.  If Sublessor has given Sublessee  written notice
pursuant to Paragraph 16.1(a) or (i) above, then Sublessor shall not be required
to  give  Sublessee  any  additional  notice  terminating  this  Sublease.  Upon
termination  of this  Sublease,  Sublessor  shall have the right to recover from
Sublessee:

(a) The worth at the time of award of the unpaid Rent and Charges which had been
earned at the time of termination:

(b) The worth at the time of award of the  amount by which the Rent and  Charges
which would have been earned after  termination  until the time of award exceeds
the amount of such rental loss that Sublessee  proves could have been reasonably
avoided;

(c) The worth at the time of award (computed by discounting at the discount rate
of the  Federal  Reserve  Bank of San  Francisco  at the time of award  plus one
percent)  of the  amount by which the Rent and  Charges  for the  balance of the
Sublease Term after the time of award exceed the amount of such rental loss that
Sublessee proves could be reasonably avoided;

(d) Any other  amounts  necessary  to  compensate  Sublessor  for all  detriment
proximately  caused by the default by Sublessee or which in the ordinary  course
of events would likely result, including without limitation any of the following
as may be permitted by law:

      (i) Expenses in retaking possession of the Premises:

      (ii) Expenses for cleaning, repairing or restoring the
      Premises;

      (iii) Any unamortized real estate brokerage  commission paid in connection
      with this Sublease;

      (iv) Expenses for removing,  transporting,  and storing any of Sublessee's
      property left at the Premises (although Sublessor shall have no obligation
      to remove, transport, or store any such property);

      (v) Expenses of reletting  the  Premises,  including  without  limitation,
      brokerage commissions and attorneys' fees;

                              - 20 -





      (vi)  Attorneys'  fees and court  costs;  and (vii) Costs of carrying  the
      Premises  such as  repairs,  maintenance,  taxes and  insurance  premiums,
      utilities and security  precautions  (if any) to the extent such costs are
      not included in the  calculation of the award  described in  subparagraphs
      (a), (b) and (c) above.

Sublessor   acknowledges   that  the   itemization  of  costs  and  expenses  in
Subparagraphs  (i)  through  (vii) above does not  constitute  an  admission  by
Sublessee  that Sublessor is permitted by law to recover such costs and expenses
or shift the  burden  of proof of  showing  entitlement  thereto  in any  action
brought on account of an Event of Default, nor does Sublessee waive its right to
challenge  the ability of  Sublessor to recover any of the costs and expenses so
itemized.

(e) The "worth at the time of award" Of the amounts referred to in subparagraphs
(a) and (b) of this  Paragraph  16.2.1 is computed  by  allowing  interest at an
annual rate equal to the greater of: 10% or 5% plus the rate  established by the
Federal  Reserve  Bank  of San  Francisco,  as of  the  25th  day  of the  month
immediately  preceding  the default by  Sublessee,  on advances to member  banks
under  Sections 13 and 13(a) of the  Federal  Reserve  Act, as now in effect or
hereafter from time to time amended, not to exceed the maximum rate allowable by
law.

16.2.2 Continuance of Sublease. Upon a default by Sublessee and unless and until
Sublessor elects to terminate this Sublease  pursuant to Paragraph 16.2.1 above,
this  Sublease  shall  continue  in effect  after the default by  Sublessee  and
Sublessor  may enforce all rights and remedies  under this  Sublease,  including
without  limitation,  the right to recover  payment of Rent and  Charges as they
become due and the right to request the appointment of a receiver to collect all
rents not otherwise payable to Sublessor by reason of any Transfer of all or any
part of the Premises or this Sublease.  Neither efforts by Sublessor to mitigate
damages  caused by a default by  Sublessee  nor the  acceptance  of any Rent and
Charges shall  constitute a waiver by Sublessor of any of Sublessor's  rights or
remedies, including the rights and remedies specified in this Paragraph 16.2.

16.2.3  Reletting  Premises.  Upon a default by  Sublessee,  Sublessor  may,  at
Sublessor's  election,  re-enter  the  Premises,  and without  terminating  this
Sublease,  and at any time and from time to time, relet the Premises or any part
or parts  thereof  for the account and in the name of  Sublessee  or  otherwise.
Sublessor may, at Sublessor's  election,  eject  Sublessee or any of Sublessee's
subtenants,  assignees  or other  person  claiming  any right in or through this
Sublease by appropriate judicial proceeding. Sublessee shall nevertheless pay to
Sublessor on the due dates  specified in this  Sublease all sums  required to be
paid by Sublessee  under this Sublease,  plus  Sublessor's  reasonable  expenses
incurred in connection with such reletting, less the proceeds of any sublease Or
reletting.  The expenses allowed Sublessor shall be expenses reasonably incurred
in the ordinary course of reletting the Premises.  which reasonable expenses may
include  without  limitation  costs paid to retake  possession  of the  Premises
(including reasonable attorneys' fees), costs to place the

                              - 21 -





Premises in its original  condition,  ordinary wear and tear excepted,  costs to
secure new tenants  (including  brokers'  commissions and reasonable  attorneys'
fees)  and  costs  to  fulfill  all of'  Sublessee's  covenants  and  conditions
hereunder to the end of the Sublease  Term.  No act by or on behalf of Sublessor
under  this  Paragraph  16.2.3  shall  constitute  a  lease  termination  unless
Sublessor gives Sublessee written notice of termination as provided in Paragraph
16.2.1.  Notwithstanding any prior reletting without termination,  Sublessor may
later elect to terminate this Sublease because of any Event of Default.

16.3 Attorneys'  Fees. The defaulting  party shall pay reasonable fees and costs
of attorneys  engaged by the  non-defaulting  party in collection of any amounts
owing or to enforce any of the non-defaulting  party's rights and remedies under
this Paragraph 16 and applicable law.

16.4 Sublessor's Default.

16.4.1  Default.  Sublessor  shall not be in default under this Sublease  unless
Sublessee  shall have given  Sublessor  written notice of the breach and, within
thirty  (30) days after  notice,  Sublessor  has not cured the breach or, if the
breach is such that it cannot reasonably be cured under the circumstances within
thirty days,  Sublessor  has not  commenced  diligently to prosecute the cure to
completion;  provided,  however, Sublessor shall have ten (10) days after notice
from Sublessee to cure any breach involving a monetary  obligation of Sublessor.
This Paragraph 16.4.1 is subject to any other provision of this Sublease wherein
Sublessee is granted the right to remedy any default by Sublessor.

16.4.2  Sublessee's  Right to Perform  Sublessor's  Obligations Under the Master
Lease.  If Sublessor shall at any time fail to make any payment of rent when due
pursuant  to the terms of  Paragraph  3 of the Master  Lease or perform  any act
required to be performed by Sublessor  when required  under the Master Lease and
notice of such  failure to perform is given by Lessor,  Sublessee  may make such
payment on three (3) days' written  notice to Sublessor,  or perform such act on
Sublessor's  behalf upon ten (10) days' written  notice to Sublessor,  but shall
not be obligated to do so and may do so without  waiving or releasing  Sublessor
from any obligation  under this Sublease.  All sums so paid by Sublessee and all
penalties,  interest  (pursuant to Paragraph  10 above),  and costs  incurred in
connection with such performance of any obligation of Sublessor shall be due and
payable by Sublessor upon demand by Sublessee,  unless  Sublessor  performs such
obligation  within the notice  period  hereunder  and  provides  Sublessee  with
written  evidence that it has performed the same, in which event Sublessor shall
have no liability to Sublessee for the foregoing.

The  foregoing  notwithstanding,  if any dispute  arises  between  Sublessor and
Lessor  over the  payment  of rent  under the  Master  Lease and  Sublessor  has
contested and is actively pursuing a resolution of said dispute, Sublessee shall
not be  entitled  to pay any rent to Lessor  which  Lessor  claims due under the
Master  Lease in excess of the rent due  pursuant to the terms of Paragraph 3 of
the Master Lease.  In such event,  Sublessor  shall protect  Sublessee's  rights
pursuant to this Sublease and prevent its termination, but without waiver of

                              - 22 -





any rights  Sublessor may have,  including  the right to withhold  payment or to
make  payment  under  protest  of all or a portion of the rent in excess of that
Sublessor believes is due to Lessor under the Master Lease.

17. Quiet Enjoyment. Sublessor covenants and agrees with Sublessee that:

(a) Upon  Sublessee  paying Rent and Charges and  performing  its  covenants and
conditions  under this Sublease,  Sublessee  shall and may peaceably and quietly
have, hold and enjoy the Premises for the Sublease Term,  subject,  however,  to
the terms of this Sublease,  the rights reserved by Sublessor  hereunder and all
matters to which this Sublease is subject and subordinate; and

(b) Sublessor  has good and  sufficient  title to the leasehold  interest in the
Premises,  free and clear of all  liens,  encumbrances,  covenants,  conditions,
restrictions,   easements,   exceptions  or  other  limitations,   except  those
covenants, conditions,  restrictions,  easements, encumbrances or exceptions now
of record or hereafter  placed of record to which this Sublease is  subordinated
as required pursuant to the Master Lease.

(c) Sublessor  will at all times save and hold  Sublessee free and harmless from
any claim, demand, cause of action or other act relating to Sublessor's title to
the leasehold  estate in the Premises (other than as expressly  provided herein)
which interferes with the quiet, peaceful and exclusive use and enjoyment of the
Premises, or any part thereof, including but not limited to reasonable costs and
attorneys'  fees  incurred  by  Sublessee  in  defending  any   interference  or
threatened inference therewith.

18.  Right of Entry.  All  references  to "Lessor" in Paragraph 16 of the Master
Lease  shall mean both  Lessor and  Sublessor.  Notwithstanding  the  foregoing,
Sublessee  shall have the right  from time to time or at any time in  connection
with the  exercise by  Sublessor  of its access  rights  hereunder  to designate
portions of the Premises as to which access shall be controlled and regulated by
Sublessee  (such as areas of the  Premises  which are subject to  regulation  on
account of Sublessee's confidentiality  requirements).  Sublessor shall abide by
the controls and regulations  imposed by Sublessee with respect to such portions
of the  Premises  and shall  also use  reasonable  efforts  to  impose  the same
requirements  on Lessor  with  respect to its  rights of access to the  Premises
under the Master Lease.

19.  Sublessor's  Right to Perform  Sublessee's  Covenants.  Except as otherwise
provided  herein,  if  Sublessee  commits an Event of  Default,  Sublessor  may,
without  further notice to Sublessee,  but shall not be obligated to and without
waiving or releasing  Sublessee  from any obligation  under this Sublease,  make
such payment or perform such other act to the extent that  Sublessor is required
pursuant  to the Master  Lease or to protect  the  Premises,  and in  connection
therewith,  pay expenses and employ  counsel.  All sums so paid by Sublessor and
ail penalties,  interest  (pursuant to Paragraph 10 above) and costs incurred in
connection  therewith  shall be due and  payable  by  Sublessee  upon  demand by
Sublessor.

                              - 23 -





20.  Surrender of Premises.  On the last day of the Sublease Term or upon sooner
termination  of  this  Sublease,  Sublessee  shall  surrender  the  Premises  to
Sublessor in good, broom clean condition (reasonable wear and tear, acts of God,
condemnation and casualties excepted), subject to the requirements of the Master
Lease. The foregoing notwithstanding,  with respect to casualties covered by the
insurance  required to be carried by  Sublessee  pursuant to Paragraph 27 of the
Master  Lease,  Sublessee  shall  assign  all  insurance  proceeds  received  by
Sublessee and payable to Lessor under the Master Lease to  Sublessor.  Sublessee
shall remove from the  Premises  all of  Sublessee's  personal  property,  trade
fixtures  and those  alterations,  improvements  and  modifications  required by
Sublessor to be removed  under  Paragraph 5 of the Master Lease as  incorporated
under  Paragraph  3.4 above,  or  required  by Lessor to be removed  pursuant to
Paragraph 5 of the Master Lease. All personal property and trade fixtures not so
removed shall be deemed  abandoned by Sublessee.  Furthermore,  Sublessee  shall
immediately repair all damage to the Premises caused by any such removal. If the
Premises are not so surrendered at termination of this Sublease, Sublessee shall
indemnify  Sublessor  against  any loss or  liability  resulting  from  delay by
Sublessee in so surrendering the Premises,  including,  without limitation,  any
claims made by any succeeding  sublessee or tenant or losses to Sublessor due to
lost opportunities to lease to succeeding tenants.

21. Option to Purchase. Subject to the provisions of Paragraphs 29 and 30 of the
Master Lease and Paragraph 22 of this  Sublease,  Sublessor  grants to Sublessee
the option to  purchase  the  Premises  during the  Sublease  Term  ("Option  to
Purchase"), provided Sublessee first exercises its option to extend the Sublease
Term for the First  Extended  Term  pursuant  to  Paragraph  4.2  above,  on the
following terms and conditions:

(a)  Notice.  Sublessee  shall  give  Sublessor's  Agent  written  notice of its
exercise  of the Option to Purchase  no earlier  than  January 1, l998 nor later
than June 30, 1998.

(b)  Automatic  Termination.  If Sublessee  (i) fails to exercise this Option to
Purchase strictly in accordance with the terms of this paragraph or (ii) assigns
this  Option to  Purchase,  other than as part of a valid  Transfer  of at least
seventy-five  percent (75%) of the Premises under Paragraph 15 above,  then this
Option to Purchase and all rights of Sublessee hereunder shall automatically and
immediately  terminate without notice, and each party shall be discharged of its
obligations  hereunder.  In addition,  upon termination of Sublessor's option to
purchase the Premises in accordance with the terms of Paragraph 29 of the Master
Lease,  Sublessee's  Option to Purchase under this Paragraph 21 shall  terminate
(except  as  provided  in  Paragraph  22.1(c)  below)  and each  party  shall be
discharged of its obligations pursuant to this Paragraph 21.

(c) Sublessor to Exercise  Option to Purchase.  If Sublessee  elects to exercise
this Option to  Purchase,  then subject to  Paragraphs  ,9n and 30 of the Master
Lease and Paragraph 22 of this Sublease,  Sublessor shall exercise its option to
purchase the Premises  from Lessor  pursuant to Paragraph 30 of the Master Lease
on behalf of Sublessee within thirty (30) days from the date Sublessee exercises
this Option to Purchase. Sublessor appoints Sublessee as its special

                              - 24 -





attorney-in-fact  solely for the  purpose of  exercising  Sublessor's  option to
purchase the Premises  from Lessor  pursuant to Paragraph 10 of the Master Lease
and  Sublessee  shall have the  nonexclusive  right to  exercise  said option in
Sublessor's  name, if and only if Sublessor has not provided  Sublessee with the
written  evidence of its  exercise  of said option to purchase  under the Master
Lease within  thirty-five  (35) days from the date Sublessee  validly  exercises
this Option to Purchase. Accordingly, Sublessor shall not be liable to Sublessee
for  Sublessor's  failure to exercise said Option to Purchase.  Each party shall
deliver  to the  other a copy  of its  exercise  notice  concurrently  with  its
delivery of the same to Lessor.  The foregoing  notwithstanding,  if an Event of
Default exists at the time Sublessee  exercises its Option to Purchase or at any
time either  party  desires or is  required  to exercise  the option to purchase
pursuant to Paragraph 30 of the Master Lease,  then at such time Sublessor shall
not be obligated to exercise its option to purchase  pursuant to Paragraph 30 of
the Master Lease for  Sublessee's  benefit nor shall Sublessee have any right to
exercise said option to purchase in Sublessor's name as special attorney-in-fact
for Sublessor.

(d) Terms of Sale.  Exercising  this Option to Purchase as provided herein shall
constitute  an  agreement  by Sublessor to sell and by Sublessee to purchase the
Premises on the following terms and conditions:

      (i)  Purchase  Price.  The  purchase  price for the Premises to be paid by
      Sublessee to Sublessor shall be equal to the quotient obtained by dividing
      the annual Rent for the First  Extended Term  (determined  pursuant to the
      terms of Paragraph 5.2 above) by .085.

      (ii)  Payment of Purchase  Price.  Subject to  Paragraph  30 of the Master
      Lease, the purchase price shall be paid by Sublessee to Sublessor, in cash
      at the close of escrow as set forth  herein.  Sublessee  shall  deposit in
      escrow,  within  thirty (30) days  following  Sublessor's  exercise of its
      option to purchase  the  Premises  pursuant to  Paragraph 30 of the Master
      Lease, either the full purchase price or five percent (5%) of the purchase
      price and the  balance in the form of  lending  commitments  from  lending
      institutions. To the extent permitted by the Master Lease, Sublessor shall
      allow Sublessee to make the election provided to Sublessor in Paragraph 30
      of the  Master  Lease  to  either  assume  the  remaining  balance  of any
      permanent loan financing  encumbering  the Premises at the time of closing
      the  transaction  contemplated  herein,  or pay any prepayment  penalty in
      connection with the early full payment  thereof.  If Lessor does not allow
      Sublessee itself to make such election, Sublessee may require Sublessor to
      make such election on Sublessee's behalf.

      (iii)  Close of Escrow.  An escrow  shall be opened at a title  company of
      Sublessor's  choice (subject to Sublessee's  reasonable  approval)  within
      thirty  (30)  days of  Sublessor's  exercise  of its  option  to  purchase
      pursuant to Paragraph 30 of the Lease. Thc close of escrow shall occur not
      later than ninety (90) days thereafter and shall occur  concurrently  with
      close of escrow  pursuant  to  Paragraph  30 under the Master  Lease.  The
      Master Lease and this  Sublease  shall  terminate  concurrently  with said
      close of escrow.

                              - 25 -





      (iv) Closing Costs. If Lessor transfers ownership of the Premises directly
      to  Sublessee,  all escrow costs and charges  shall be  allocated  between
      Lessor and Sublessee as provided in Paragraph 30 or the Master  Lease.  If
      Sublessor  must  first  purchase  the  Premises  from  Lessor on behalf of
      Sublessee, all escrow costs and charges (including, without limitation any
      prepayment penalties charged to Sublessor pursuant to said Paragraph 30 or
      payable  by  Sublessee  pursuant  to  Paragraph  21(d)(ii)  above) for the
      transfer  of the  Premises  from  Lessor  to  Sublessor,  and  payable  by
      Sublessor  under  Paragraph 30 of the Master Lease shall be  reimbursed to
      Sublessor  by  Sublessee  at the close of escrow  of the  transfer  of the
      Premises  from  Sublessor  to  Sublessee.  All  escrow  costs and  charges
      incurred in the transfer of the Premises from Sublessor to Sublessee shall
      be paid by Sublessee.

      (v) Condition of Title.  Sublessee shall take title to the Premises in the
      same  condition  Lessor is  required  to convey  title to the  Premises to
      Sublessor pursuant to Paragraph 30 of the Master Lease.

(e) No Warranties.  Subject to the repair and maintenance  obligations of Lessor
and Sublessor and solely in Sublessee's  capacity as purchaser under this Option
to Purchase,  Sublessee  hereby:  (i)  acknowledges  that it has  inspected  the
Premises and observed its physical  characteristics and conditions;  (ii) waives
any and all  objections to said physical  characteristics  and conditions of the
Premises which would be disclosed by such  inspection;  (iii)  acknowledges  and
agrees that the Premises is accepted by Sublessee in its present condition,  "as
is," and that no patent or latent physical  condition of the Premises whether or
not known or  discovered,  shall affect the rights of either party hereto;  (iv)
has  investigated and has knowledge of operative or proposed  governmental  laws
and regulations  including,  but not limited to, zoning,  environmental and land
use laws and  regulations  to which the  Premises  may be  subject;  and (v) has
neither  received nor relied upon any  representations  concerning such laws and
regulations  made by  Sublessor  or any other  person  acting on or in behalf of
Sublessor.

(f) Time.  Time is of the essence of this Option to  Purchase.  If the Option to
Purchase is not  exercised  in the manner  provided  herein,  then the Option to
Purchase  shall  terminate and may not be revived by any  subsequent  payment or
further action by Sublessee.

(g) Right to Exchange.  Sublessee  acknowledges  Lessor's  right to exchange the
Premises,  pursuant to Internal Revenue Code Section 1031, for one or more other
properties  of like kind,  and agrees to  cooperate  in and  facilitate  such an
exchange and to accept conveyance of and acquire the Premises from a third party
should  Lessor  elect to enter into such an  exchange  prior to the date set for
close of escrow under the Option to Purchase,  so long as Sublessee  shall incur
no additional costs, fees, expenses, obligations or liabilities thereby.

(h)  Notice  Binding  Subject  to the  provisions  Of this  Paragraph  21,  once
Sublessee  delivers notice of its exercise of the Option to Purchase,  Sublessee
may not withdraw such exercise.

                              - 26 -





(i) Limitation of Obligations of Sublessor; Indemnification.  Except as provided
in this  Paragraph  21 and unless  required to do so to  exercise  the option to
purchase  pursuant to Paragraph 30 of the Master Lease (in which event Sublessor
shall be reimbursed by Sublessee  upon the close of escrow for the conveyance of
the Premises from  Sublessor to Sublessee),  Sublessor  shall not be required to
incur any costs or assume any evidence of  indebtedness  in connection  with its
exercise of the option to purchase  pursuant to Paragraph 30 of the Master Lease
on behalf of Sublessee.  Sublessee  shall  indemnify,  defend,  protect and hold
Sublessor  harmless  from and  against  any and all  losses,  costs,  claims  or
liability arising in connection with the acquisition and conveyance by Sublessor
of the Premises and any required  assumption of indebtedness,  other than as may
arise due to neglect, an act, or a default hereunder by Sublessor. The indemnity
and hold harmless obligation shall exist whether or not escrow between Sublessor
and  Sublessee  closes,  and shall  survive the close of escrow with  respect to
Sublessor and Lessor,  the close of escrow between Sublessor and Sublessee,  and
shall not merge with any deed or conveyance executed by Sublessee.

22. Right of First Refusal.

22.1 Sublessee's Right to Exercise Right of First Refusal. If Sublessor receives
notice  from Lessor  pursuant to  Paragraph  29 of the Master  Lease  during the
Sublease Term on or before June 30, 1998, then Sublessor grants to Sublessee the
right to require  Sublessor to exercise  Sublessor's  right of first  refusal as
provided in Paragraph 29 of the Master Lease and thereafter  convey the Premises
to Sublessee on the following terms and conditions:

(a) Within three (3) days of receiving  Lessor's notice of any offer to purchase
all or a portion of the  Premises or Lessor's  offer to sell all or a portion of
the Premises  pursuant to Paragraph 29 of the Master Lease ("Lessor's  Notice"),
Sublessor shall provide Sublessee with a copy of Lessor's Notice.

(b)  Sublessee  shall have eight (8) days from  receipt  of  Lessor's  Notice to
notify  Sublessor's  Agent in writing of  Sublessee's  election to exercise  the
right of first  refusal  offered in  Lessor's  Notice.  If  Sublessee  elects to
exercise the right of first refusal offered in Lessor's  Notice,  then Sublessor
will exercise its right of first refusal  pursuant to Paragraph 29 of the Master
Lease on behalf of  Sublessee  (subject  to the terms of  Paragraph  22.3 below)
within  five (5) days from  receipt  of  Sublessee's  Notice of its elect ion to
exercise.

(c) If  Sublessee  elects not to exercise  Its first right to the right of first
refusal offered in Lessor's Notice or fails to notify  Sublessor's  Agent within
said eight (8) day period, then Sublessor's Agent shall have eight (8) days from
receipt of Sublessee's  notice of  non-election  (or from the expiration of said
eight  (8)  Way  period,  whichever  occurs  earlier)  to  notify  Sublessee  of
Sublessor's  election to exercise  said right of first refusal on its own behalf
or not to exercise said right of first refusal.  If Sublessor elects to exercise
said  right of first  refusal  on its own  behalf,  then  Sublessee's  Option to
Purchase pursuant to Paragraph 21

                              - 27 -





above  shall  remain in full  force  and  effect  in  accordance  with the terms
thereof.  (d) If  Sublessor  elects not to exercise  the right of first  refusal
offered in Lessor's  Notice  pursuant  to  subparagraph  (c) above,  or fails to
notify  Sublessee  within said additional  eight (8) day period,  then Sublessee
shall  have  five (5)  days  from  receipt  of  Sublessor's  Agent's  notice  of
non-election  (or from the  expiration  of said eight (8) day period,  whichever
occurs earlier) to notify Sublessor's Agent of Sublessee's  election to exercise
said right of first  refusal.  If  Sublessee  so elects to exercise the right of
first refusal offered in Lessor's Notice, then Sublessor will exercise its right
of first  refusal  pursuant  to  Paragraph  29 of the Master  Lease on behalf of
Sublessee  (subject to the terms of Paragraph  22.3 below)  within five (5) days
from receipt of  Sublessee's  Notice of its  election to exercise.  If Sublessee
does not  elect to  exercise  the right of first  refusal  offered  in  Lessor's
Notice, then the Option to Purchase shall terminate, and Sublessee shall have no
further right to acquire the Premises.

(e) If Sublessee  elects not to exercise the right of first  refusal  offered in
Lessor's  Notice  pursuant  to  subparagraph  (d)  above,  or  fails  to  notify
Sublessor's  Agent within said five (5) day period,  then Sublessor may exercise
its right of first  refusal on its own behalf  pursuant to  Paragraph  29 of the
Master  Lease,  free  and  clear of any  right of  Sublessee  to the  Option  to
Purchase.

22.2  Attorney-in-Fact.  If  Sublessee  elects  to  exercise  the right of first
refusal,  Sublessor shall exercise its right of first refusal under Paragraph 29
of the Master Lease  within the time periods set forth in Paragraph  22.1 above.
Sublessor  appoints  Sublessee  as its special  attorney-in-fact  solely for the
purpose of exercising  Sublessor's  right of first refusal pursuant to Paragraph
29 of the Master  Lease,  and  Sublessee  shall have the  nonexclusive  right to
exercise  such  right of  first  refusal  in  Sublessor's  name,  if and only if
Sublessor has not provided  Sublessee  with written  evidence of its exercise of
said right of first refusal  within the time periods set forth in Paragraph 22.1
above.  Accordingly,  Sublessor shall not be liable to Sublessee for Sublessor's
failure to exercise said right of first refusal. Each party shall deliver to the
other a copy of its exercise notice  concurrently  with its delivery of the same
to Lessor. The foregoing  notwithstanding,  if an Event of Default exists at the
time Sublessee  exercises the right of first refusal  pursuant to this Paragraph
22 or at any time either  party  desires or is required to exercise the right of
first  refusal  under  Paragraph  29 of the  Master  Lease,  then at  such  time
Sublessor shall not be obligated to exercise the right of first refusal pursuant
to Paragraph 29 of the Master Lease for Sublessee's  benefit nor shall Sublessee
have any right to exercise  said right of first refusal in  Sublessor's  name as
special attorney-in-fact for Sublessor.

22.3 Terms of Sale.  If  Sublessee  timely and validly  exercises  said right of
first  refusal as  provided  above,  then the Master  Lease and  Sublease  shall
terminate  upon  acquisition  by  Sublessee of fee title to the  Premises.  Such
exercise by Sublessee shall constitute an agreement by Sub-

                              - 28 -





lessor to sell and by Sublessee to purchase the Premises on the
terms and conditions of Lessor's Notice, except as set forth
below:
(a) Purchase Price. The purchase price to be paid for the
Premises by Sublessee to Sublessor shall be equal to the sum of:

      (i) The amount to be paid by Sublessor  for the  Premises  pursuant to the
      right of first refusal under Paragraph 29 of the Master Lease; plus

      (ii) The present value at the time of payment,  if applicable,  determined
      by applying a discount  rate of nine percent (9%) per annum of the excess,
      if any, of the  purchase  price under the Option to  Purchase,  calculated
      pursuant to Paragraph  21(d)(i)  above,  over the purchase price under the
      right of first refusal; plus

      (iii) The present value at the time of payment  (determined  by applying a
      discount  rate of nine  percent  (9%) per annum) of the excess of the Rent
      that would be payable by Sublessee  hereunder  over the rent that would be
      payable by Sublessor to Lessor pursuant to the Master Lease (assuming rent
      is  calculated  as  provided in  Amendment  #3) for the  remaining  months
      (prorated  based on the number of days in the  particular  month,  for any
      partial month) in the initial Sublease Term beginning with the date escrow
      closes on  Sublessee's  purchase of the Premises  under the right of first
      refusal and ending with the last month of the tenth (10th)  calendar  year
      of the Sublease Term (December 31, 1997); plus

      (iv) The present value at the time of payment,  if applicable,  determined
      by applying a discount  rate of nine  percent (9%) per annum of the excess
      of the Rent that would be payable by Sublessee  hereunder  (determined  in
      accordance with 2203(b)(iii)  below),  over the rent that would be payable
      by Sublessor  to Lessor  pursuant to the Master  Lease  (assuming  rent is
      calculated as provided in Amendment #3) for the eleventh  (11th)  calendar
      year of this Sublease (January 1, 1998 through December 31, 1998).

(b) Payment of Purchase Price.  The purchase price shall be paid by Sublessee to
Sublessor as follows:

      (i) The amount set forth in  Paragraph  22.3(a)(i)  above shall be paid in
      the manner set forth in Lessor's Notice;

      (ii) The  amount  set  forth  in  Paragraph  22.3(a)(iii)  shall  be  paid
      to Sublessor's Agent in rash at close of escrow: and

      (iii)  The  parties  hereto  recognize  that  the  amounts  set  forth  in
      Paragraphs  22.3(a)(ii) and 22.3(a)(iv)  above cannot be determined  until
      the tenth (10th) year of the Sublease  Term,  as provided in Paragraph 5.2
      above,  at which  time this  Sublease  and the  Master  Lease  shall  have
      terminated pursuant to the provisions of this Paragraph 22.  Nevertheless,
      in order to determine the amounts set forth in Paragraphs  22.3(a)(ii) and
      22.3(a)(iv)  above,  the parties  shall first attempt to agree on the Rent
      which would have been payable  hereunder during the First Extended Term at
      the time

                              - 29 -





      of exercise by Sublessee of said right of first refusal. If, at such time,
      the  parties  agree  oaths Rent which  would have been  payable  hereunder
      during the First Extended Term,  then Sublessee  shall pay to Sublessor at
      close of escrow,  the  amounts  set forth in  Paragraphs  22.3(a)(ii)  and
      22.3(a)(iv)  based on such agreed-to rent,  discounted to present value as
      of the date of payment at the rate of nine percent (9%) per annum.  If the
      parties cannot reach agreement on such Rent for the First Extended Term at
      the time the right of first  refusal is exercised by  Sublessee,  then the
      parties  shall utilize the  procedures  set forth in Paragraph 5.2 of this
      Sublease  beginning on May 1, 1997,  which is the last date  Sublessee may
      exercise  its option to extend the  Sublease  Term for the First  Extended
      Term. If the  procedures set forth in Paragraph 5.2 above must be utilized
      at a future  date,  the amounts set forth in  Paragraphs  22.3(a)(ii)  and
      22.3(a)(iv)  shall be determined no later than December 31, 1997 and shall
      be payable in full to Sublessor by Sublessee on or before January 1, 1998.

(c) Close of Escrow. Close of escrow between Sublessor and Sublessee shall occur
concurrently  with close of escrow  between  Lessor and  Sublessor,  which shall
occur pursuant to the terms of Lessor's notice.

(d) Closing  Costs.  All escrow costs and other  charges for which  Sublessor is
responsible  in  connection  with the  transfer of the  Premises  from Lessor to
Sublessor shall be paid by Sublessee.  All escrow costs and charges  incurred in
the  transfer of the  Premises  from  Sublessor  to  Sublessee  shall be paid by
Sublessee.

22.4 Limitations on Sublessor's  Obligations;  Indemnification.  Sublessor shall
not be  required  to incur any costs,  assume any  secured  loan or execute  any
promissory  note or  other  evidence  of  indebtedness  in  connection  with its
exercise of said right of first refusal on behalf of Sublessee  (unless required
to do so to exercise the right of first refusal  pursuant to Paragraph 29 of the
Master Lease,  in which event  Sublessor  shall be reimbursed by Sublessee  upon
close of escrow for the conveyance of the Premises from Sublessor to Sublessee).
Sublessee shall indemnify, defend, protect, and hold Sublessor harmless from and
against any and all losses,  costs,  claims or liability  arising in  connection
with the  acquisition  and  conveyance  by  Sublessor  of the  Premises  and any
required assumption of indebtedness,  other than as may arise due to neglect, an
act, or a default  hereunder  by  Sublessor.  The  indemnity  and hold  harmless
obligation  shall exist  whether or not escrow  between  Sublessor and Sublessee
closes,  and shall  survive the close of escrow with  respect to  Sublessor  and
Lessor, the close of escrow between Sublessor and Sublessee, and shall not merge
with any deed or conveyance executed by Sublessee.

23. Property Loss; Damage.

23.1  Waiver  of  Claims.  The  terms of  Paragraph  27(b) of the  Master  Lease
notwithstanding,  and  except to the  extent  caused by the  active  negligence,
omission  to act after  written  notice  from  Sublessee  of the need to act, or
willful misconduct of Sublessor or its agents or employees,  or by the breach by
Sublessor of any  obligation  under this Sublease or the Master  Lease,  neither
Sublessor nor its agents or employees shall be liable for any damage to property
of

                              - 30 -





Sublessee,  nor for loss of or damage to any  property of  Sublessee by theft or
otherwise,  nor for any injury or damage to persons or property  resulting  from
any cause of whatsoever nature.

23.2 Waiver of Subrogation.  Sublessor hereby releases Sublessee,  and Sublessee
hereby releases Sublessor, and their respective officers,  agents, employees and
servants, from any and all claims or demands of damages, loss, expense or injury
to  the  Premises,  or the  improvements,  alterations,  furnishings,  fixtures,
equipment,  inventory or other  property of either  Sublessor  or Sublessee  in,
about or upon the Premises, which is caused by or results from perils, events or
happenings which are the subject of insurance carried by the respective  parties
pursuant  to this  Sublease  or  otherwise  carried  by the  respective  parties
covering the Premises and in force at the time of any such loss,  whether due to
the  negligence,  of the other  party or its agents and  regardless  of cause or
origin; provided, however that such waiver shall be effective only to the extent
permitted by the insurance  covering such loss and to the extent such  insurance
is not prejudiced thereby.

23.3  Indemnification.  Sublessee  shall  indemnify,  hold harmless,  and defend
Sublessor (except with respect to Sublessor's active negligence, omission to act
after  notice of the need to act,  or willful  misconduct)  against  all claims,
losses or liabilities for injury or death to any person or for damage to or loss
of use of any  property  arising  out of any  occurrence  in,  on or  about  the
Premises caused or contributed to by Sublessee or Sublessee's agents, or arising
out of any  occurrence  in,  upon or at the  Premises  or on account of the use,
condition,  occupational  safety or occupancy of the Premises.  Sublessor  shall
indemnify,   hold  harmless,  and  defend  Sublessee  (except  with  respect  to
Sublessee's active negligence,  omission to act after notice of the need to act,
or willful misconduct)  against all claims,  losses or liabilities for injury or
death to any person or for damage to or loss of use of any property  arising out
of any  occurrence  in, on or about the  Premises  caused or  contributed  to by
Sublessor or Sublessor's agents, or arising out of any occurrence in, upon or at
the  Premises  on the  account  of the use,  condition,  occupational  safety or
occupancy of the  Premises.  The  preceding  indemnifications  shall include and
apply to attorneys' fees, investigation costs, and other costs actually incurred
by  Sublessor  or  Sublessee,  as the case may be. Each party  shall  indemnify,
defend and hold  harmless  the other  party from and against any and all claims,
losses,  liabilities  or  damages  arising  from any  breach or  default  in the
performance of any obligation to be performed  under the terms of this Sublease.
The provisions of this Paragraph 23.3 shall survive  termination of the Sublease
with respect to any damage,  injury, death. breach or default occurring prior to
such termination.

24. General.

24.1  Captions and Headings.  The captions and  paragraph  headings used in this
Sublease are for  convenience of reference  only. They shall not be construed to
limit or  extend  the  meaning  of any part of this  Sublease,  and shall not be
deemed relevant in resolving any question of  interpretation  or construction of
any paragraph of this Sublease.

                              - 31 -





24.2  Surrender of Sublease Not Merger.  Subject to the provisions  hereof,  the
voluntary  or  other  surrender  of this  Sublease  by  Sublessee,  or a  mutual
cancellation  thereof,  shall  not work a merger  and  shall,  at the  option of
Sublessor, terminate all or any existing sub-subleases, or may, at the option of
Sublessor,   operate  as  an   assignment  to  Sublessor  of  any  or  all  such
sub-subleases. The foregoing notwithstanding and subject to the Master Lease, if
(i)  Sublessor's  consent to the Transfer was requested and given at the time of
the Transfer;  (ii) a sub-sublessee  of the entire Premises or a portion thereof
is paying rent which is equal to or greater than the Rent (or allocable  portion
calculated  on a "per square foot" basis if the  Transfer  affects less than the
entire  Premises)  paid by  Sublessee  hereunder  during the entire  term of the
sub-sublease;   (iii)  the  portion  of  the   Premises   not  subject  to  such
sub-sublease(s) is, in Sublessor's reasonable judgment,  leaseable,  independent
of the  portion  of the  Premises  subject  to such  sub-sublease(s);  (iv) such
subsublessee is creditworthy,  in Sublessor's  reasonable judgment, and (v) such
sub-sublessee  is not in  default  under  the  terms of its  sub-sublease,  then
Sublessor shall permit such sub-sublease to remain in full force and effect.

24.3  Interpretation  of Terms.  The words  "Sublessor"  and "Sublessee" as used
herein  shall  include the plural as well as the  singular.  Words in the neuter
gender include the masculine and feminine and words in the masculine or feminine
gender include the neuter.

24.4 Counterparts.  This Sublease may be executed in counterparts, each of which
shall be deemed an original for all purposes and together  shall  constitute one
instrument.

24.5 Time of Essence.  Time is of the essence as to each and every  provision in
this Sublease requiring performance within a specified time.

24.6  Severability.  In case any one or more of the provisions  contained herein
shall for any  reason be held to be  invalid,  illegal or  unenforceable  in any
respect,  such invalidity,  illegality or unenforceability  shall not affect any
other  provision of this  Sublease,  but this Sublease  shall be construed as if
such invalid,  illegal or unenforceable provision had not been contained herein.
However,  if  Sublessee's  obligation to pay Rent is determined to be invalid or
unenforceable, this Sublease at the option of Sublessor shall terminate.

24.7  Governing Law. This Sublease shall be construed and enforced in accordance
with the laws of the State of California.

24.8 Joint and Several  Liability.  If Sublessee  is more than one person,  each
such person or entity shall be jointly and severally  liable for the obligations
of Sublessee hereunder.

24.9 Construction of Sublease  Provisions.  This Sublease shall not be construed
either  for or  against  Sublessee  or  Sublessor,  but  shall be  construed  in
accordance  with the general tenor of the language to reach a fair and equitable
result.

                              - 32 -





24.10  Sublessor or Sublessee  as Party  Defendant.  If, by reason of any act or
omission by either  party or either  party's  agents,  the other party is made a
party defendant in any action,  proceeding or suit concerning this Sublease,  or
the Premises, the party responsible for said act or omission shall indemnify the
other party against all  liability  incurred (or  threatened  against) the other
party as a party defendant, including all damages, costs and attorneys' fees.

24.11 Sublessor Not a Trustee.  Sublessor shall not be deemed to be a trustee of
any funds paid to Sublessor by Sublessee  (or held by Sublessor  for  Sublessee)
pursuant  to this  Sublease.  Sublessor  shall not be  required to keep any such
funds  separate  from  Sublessor's  general  funds.  Any funds held by Sublessor
pursuant to this Sublease shall not bear interest.

24.12 No  Partnership  or  Joint  Venture.  Nothing  in this  Sublease  shall be
construed  as  creating  a  partnership  or  joint  venture  between  Sublessor,
Sublessee,  or any other party,  or cause either party to be responsible for the
debts or obligations of the other party or any other party.

24.13  Exhibits.  All exhibits  attached to this Sublease  shall be deemed to be
incorporated  herein by the individual  reference to each such exhibit,  and all
such  exhibits  shall be deemed a part of this  Sublease  as though set forth in
full in the body of the Sublease.

24.14  Attorneys'  Fees. The provisions of Paragraph 22 of the Master Lease,  as
incorporated herein, shall also apply to any action or proceeding by, against or
concerning  either party under any federal or state  bankruptcy,  insolvency  or
other debtor's relief law.

24.15 Indemnities to Survive Sublease.  The indemnities of the parties set forth
in this Sublease  shall survive the  expiration or earlier  termination  of this
Sublease.

24.16  Attorney-in-Fact.  Provided the Sublease is then in full force and effect
and no  Event  of  Default  then  exists,  Sublessee's  appointment  as  special
attorney-in-fact  for the purposes  described in this  Sublease is  irrevocable,
coupled with an interest and shall survive the transfer of Sublessor's  interest
in the Premises or the insolvency, dissolution, or bankruptcy of Sublessor.

25. Entire Agreement. This Sublease, together with al' exhibits attached hereto,
are  the  entire  agreement  between  the  parties,  and  there  are no  binding
agreements or  representations  between the parties except as expressed  herein.
Any agreements,  warranties or  representations  not expressly  contained herein
shall in no way bind either Sublessor or Sublessee,  and Sublessor and Sublessee
expressly   waive  all   claims  for   damages  by  reason  of  any   statement,
representation,  warranty,  promise or agreement,  if any, not contained in this
Sublease.   This   Sublease   supersedes   and  cancels  any  and  all  previous
negotiations,  arrangements,  brochures, agreements and understandings,  whether
written or oral,  between  Sublessor and its agents and Sublessee and its agents
with  respect  to  the  Premises  and  appurtenances   thereto.   This  Sublease
constitutes the entire agreement between the parties hereto and no

                              - 33 -





addition to, or modification of, any term or provision of this Sublease shall be
effective  until and  unless  set forth in a written  instrument  signed by both
Sublessor  and  Sublessee.  26.  Real Estate  Brokers.  Sublessor  warrants  and
represents  to  Sublessee  that  it  has  dealt  with  Cooper/Brady   Commercial
Industrial Real Estate ("Cooper/Brady") and Sublessor and Sublessee each warrant
and represent to the other that neither has authorized or employed,  or acted by
implication to authorize or to employ,  any other real estate broker or salesman
or other person to act for  Sublessor or Sublessee,  respectively  in connection
with this Sublease.  Each party shall indemnify and defend the other against and
hold the other harmless from all claims, demands, liabilities,  damages, losses,
costs and expenses,  including, without limitation,  reasonable attorneys' fees,
arising from any claim for any  compensation,  commission or finder's fee by any
real  estate   broker  or  salesman  or  other  person   actually  or  allegedly
representing  or  acting  on  behalf  of  the  indemnifying   party  other  than
Cooper/Brady.

Sublessee  represents  and warrants that no agreement,  oral or written,  exists
between  Sublessee  and  Cooper/Brady  for  the  payment  by  Sublessee  of  any
commission  or other  compensation  in  connection  with  this  Sublease  or any
transaction contemplated hereunder.  Sublessor shall indemnify,  defend and hold
Sublessee harmless from all claims, demands, liabilities, damages, losses, costs
and expenses,  including without limitation  reasonable attorneys' fees, arising
from any claim by Cooper/Brady for commissions owing.

27. Subordination.  Except to the extent otherwise required by the Master Lease,
nothing in this Sublease shall subordinate Sublessee's leasehold interest in the
Premises to any deed of trust,  mortgage,  or instrument  of security  affecting
Sublessor's  leasehold  interest,  and  Sublessee's  attornment  to any party is
conditioned upon (i) recognition and continuation of this Sublease following any
foreclosure  of a deed of trust,  mortgage  or security  interest;  and (ii) the
performance by the holder of the interest to which this Sublease is subordinated
of all  obligations to be performed by the Sublessor  under this Sublease on and
after the date of the holder's succession to an interest in the Premises.

28. Hazardous Materials.

28.1 Definitions.  As used in this Sublease, the term "Hazardous Material" shall
mean any substance,  material or waste which has been determined or is hereafter
determined by any state,  federal or local governmental  authority to be capable
of posing a risk of injury or adverse effect (temporary or otherwise) to health,
safety, property,  and/or environment,  and, as a result, the use or presence of
which is now or hereafter  regulated by such government  entity,  or which must,
under  applicable  federal.  state or local laws,  rules or regulations or court
decrees  be removed or  otherwise  remediated  by the owner of the land or other
responsible parties if a release thereof occurs,  including, but not limited to,
all of those materials, substances or wastes designated as hazardous or toxic by
the Environmental Protection Agency, the California Water Quality Control Board,
the U.S. Department of Labor, the California Department of Industrial Relations,
the U.S. Department of Transportation,

                              - 34 -





the California Department of Food & Agriculture, the U. S. Department of Health,
Education and Welfare, the California Department of Health Services or any other
local, state or federal  governmental agency or authority actually regulating or
now or  hereafter  authorized  to  regulate  hazardous  or toxic  materials  and
substances in the environment. Without limiting the generality of the foregoing,
the  term  "Hazardous  Material"  shall  include  all  of  those  materials  and
substances  (i) defined as "toxic  materials" in Sections 66680 through 66685 of
Title 22 of the California  Administrative  Code, Division 4, Chapter 30, as the
same may be  amended  from time to time,  or (ii) any other  hazardous  or toxic
substance,  material  or  waste  which  is or  becomes  regulated  by any  local
governmental  authority,  any agency of the State of California or any agency of
the United  States  Government,  as the above may be amended  from time to time.
Sublessee has provided  Sublessor with a list of all Hazardous  Materials  which
Sublessee  plans to use or anticipates it will use on the Premises and Sublessee
shall notify  Sublessor  from time to time during the Sublease Term if Sublessee
plans to use any additional Hazardous Materials on the Premises not contained on
the list ("Permitted Hazardous Materials").

28.2 Use of Premises and Compliance With Laws. Neither Sublessee nor Sublessee's
employees,  agents,  contractors,  assignees,  sub-sublessees  or invitees shall
permit the introduction, placement, use, storage or disposition of any Permitted
Hazardous  Materials in or about the Premises  unless such  Permitted  Hazardous
Materials are contained, stored, used and disposed in a safe manner and strictly
in  accordance  with all  federal,  state and local laws and  government  rules,
regulations and guidelines and, all necessary  permits and licenses from any and
all regulatory agencies having jurisdiction have been obtained.  Sublessee shall
clean,  decontaminate or otherwise correct the effects of any such introduction,
placement,  use,  storage or disposition of Hazardous  Materials in or about the
Premises during the Sublease Term by Sublessee,  Sublessee's employees,  agents,
contractors, assignees, sub-sublessees, invitees or any other third party on the
Premises, in the manner and in accordance with the requirements set forth above.
Sublessee shall indemnify,  defend, protect and hold Sublessor harmless from and
against  all  costs  incurred  by  Sublessor  resulting  from a  breach  of this
Paragraph 28.2.

28.3 Notice.  Sublessee shall immediately  notify Sublessor of any breach of the
requirements  set forth in Paragraph 28.2 above.  In addition,  Sublessee  shall
immediately notify Sublessor of any inquiry, test,  investigation or enforcement
proceeding  by or against  Sublessee,  or the  Premises  involving  a  Hazardous
Material.  The results of any  inquiry,  test,  or  investigation  conducted  by
Sublessee or  Sublessee's  employees,  agents or  contractors  to determine  the
presence of Hazardous  Materials in and about the Premises  shall be provided to
Sublessor  promptly  upon receipt of such  results by  Sublessee or  Sublessee's
employees,  agents or  contractors,  but Sublessee and Sublessor shall otherwise
use reasonable good faith efforts to keep such information confidential,  except
to the extent  that  disclosure  of such  information  is required by law. If an
Event of Default exists with respect to this Paragraph 28,  Sublessor shall have
the right, at Sublessee's cost and expense,  to negotiate,  defend,  approve and
appeal any action taken or order issued by an applicable

                              - 35 -





governmental  authority concerning such Hazardous Material.  If such an Event of
Default does not exist, Sublessor may nevertheless,  but at Sublessor's cost and
without  unreasonably  interfering  with  Sublessee's  actions,  participate  in
Sublessee's  negotiations,  defense,  approval or appeal of any action  taken or
order issued.

28.4  Indemnification.  Sublessee  shall  indemnify,  hold harmless,  and defend
Sublessor  against  all  costs  (including  without  limitation  the cost of any
studies  or  investigations  to  determine  the  nature,  extent  and/or  proper
remediation of any Hazardous Material), claims, losses or liabilities for injury
or death to any person,  or for damage to or loss of use of any  property or the
environment,  arising out of or in connection with the introduction,  placement,
use,  storage or disposition of any Hazardous  Material in or about the Premises
by  Sublessee,  or  Sublessee's  employees,   agents,  contractors,   assignees,
sub-sublessees  or invitees or any other third party on the Premises  during the
Sublease Term and the removal or clean-up of such Hazardous Materials, including
the payment of any fines and penalties  levied in connection  with such actions,
or  discharging  any  lien  on the  Premises  securing  the  foregoing  cost  of
correction.

28.5 Charges.  All costs payable by Sublessee under this Paragraph 28 during the
Sublease Term shall be paid by Sublessee to Sublessor upon demand, as Charges.

28.6 Liens.  Sublessee shall not cause or suffer any lien to be recorded against
the Premises as a  consequence  of, or in any way related to, the  introduction,
placement,  use,  storage or disposition  of Hazardous  Material in or about the
Premises by Sublessee or Sublessee's employees, agents, contractors,  assignees,
sub-sublessees  or invitees or any other third party on the Premises  during the
Sublease Term and the removal or clean-up of such Hazardous Materials, including
any so-called state, federal or local "super fund" lien relating thereto. To the
extent permitted by the Master Lease,  Sublessee shall have the right to contest
the  payment of any lien  described  herein in the name of Lessor (to the extent
permitted by the Master  Lease),  in the name of Sublessor,  or in its own name.
Sublessor shall execute all documents necessary or appropriate to effectuate the
contest  and will use  reasonable  efforts to cause  Lessor to do the same.  Any
steps, actions or proceedings instituted by Sublessee shall be at the expense of
Sublessee.  Sublessee  shall  indemnify  and hold  Sublessor  harmless  from and
against all loss, costs,  liability,  claims,  damages,  and expenses (including
without limitation,  reasonable attorneys' fees), penalties,  and fines incurred
in connection with or arising from such contest by Sublessee.

28. Sublessor's Right of Access.  Subject to Paragraph 18 above, Sublessor shall
have the right to enter upon the Premises if Sublessor  has  reasonable  grounds
for doing so and with reasonable prior written notice (except in the event of an
emergency,  in which  case no  notice  shall be  required)  for the  purpose  of
performing tests to determine the existence and extent of Hazardous Materials in
or about the Premises. In performing such tests,  Sublessor shall use reasonable
efforts to cause the least interference with Sublessee's business operations and
shall,  upon  completion  of the tests,  restore the  Premises to the  condition
existing prior to per-

                              - 36 -





forming such tests.  Sublessor shall indemnify and hold Sublessee and its agents
harmless  from any loss,  claim,  liability  or  expense,  including  reasonable
attorneys'  fees,  arising  out of,  or in  connection  with  such  entry on the
Premises or the performance of such tests or work.

28.8 Assignment and Subletting.  Notwithstanding anything contained in Paragraph
15 above to the contrary, it shall be presumptively  reasonable for Sublessor to
withhold  its  consent to any  proposed  assignment  or  subletting,  if (i) the
proposed  assignee's or  sub-sublessee's  anticipated use of the Premises or any
portion  thereof  involves  the   introduction,   placement,   use,  storage  or
disposition of any Hazardous  Materials  considered  ultra-hazardous  by law, or
(ii) if the  proposed  assignee or  sub-sublessee  (A) has been  required by any
prior owner, sublessor,  lender or governmental authority to clean up and remove
any  Hazardous  Material,  or (B) is subject or has been  subject in the past to
investigation or enforcement orders or proceedings by any governmental agency or
authority  in  connection  with  the  introduction,   placement,  use,  storage,
disposition or clean-up of Hazardous  Material,  to an extent that the existence
of  the  facts  described  in  either  subparagraph  (A) or  (B)  indicates,  in
Sublessor's  reasonable judgment, a pattern of conduct or behavior of the misuse
of Hazardous Materials.

29.  Memorandum of Sublease.  In connection with the execution of this Sublease,
Sublessor and  Sublessee  shall  execute in  recordable  form, a "Memorandum  of
Sublease,  Option to  Purchase  and  Right of First  Refusal"  referencing  this
Sublease  document  and  setting  forth  the  true  and  legal  description  and
assessor's parcel number of the Premises, in the form attached hereto as Exhibit
"B" for recordation in the Official Records of Santa Clara County, California.

30.  Sublessor's  Undertaking  With Respect to Master  Lease.  Sublessor  hereby
represents  and warrants to Sublessee that the copy of the Master Lease attached
hereto as Exhibit "A" is a true and complete copy of the Master Lease,  and that
to Sublessor's  knowledge the Master Lease is in full force and effect, and that
there is no default on the part of any party  thereto  nor any facts  which with
notice,  the passage of time, or both,  would  constitute a default by any party
under the  Master  Lease.  Sublessor  shall  perform  those  obligations  of the
"Lessee"  under the Master Lease which are not the  obligations  of Sublessee to
perform pursuant to the terms of this Sublease,  unless Sublessor's  performance
is excused hereunder by reason of the existence of an Event of Default.

31.  Covenant  of Good  Faith and Fair  Dealing.  Subject to the  provisions  of
Paragraph  16 above,  no party shall do anything  which shall have the effect of
harming or injuring the right of the other party to receive the benefits of this
Sublease;  each party shall refrain from doing  anything  which would render its
performance under this Sublease  impossible;  and each party shall do everything
which this Sublease contemplates that such party shall do in order to accomplish
the objectives and purposes of this Sublease.

32. Sublessor's Agent. Sublessor warrants that Sublessor's Agent is the agent of
Sublessor  and,  as to those  matters  with  respect  to  which it is  expressly
provided under this Sublease that Sublessor's Agent may act on behalf of

                              - 37 -





Sublessor,  for purposes of this Sublease, has the authority to so act on behalf
of  Sublessor,  upon which acts  Sublessee  may rely.  IN WITNESS  WHEREOF,  the
parties  have  executed  this  Sublease  effective as of the last date set forth
below ("Effective Date").

SUBLESSOR:

McDONNELL DOUGLAS CORPORATION, a Maryland corporation

By /s/ John Elbert
Its Vice Present Controller,
Network Systems Company, a division of Information Systems Group,
a division of McDonnell Douglas Corporation

Dated: 11/11/87

SUBLESSEE:

APPLE COMPUTER, INC., a California corporation

By /s/ Albert A. Eisenstat
ALBERT A. EISENSTAT,
Senior Vice President

Dated: 11/13/87

By
Secretary





                                    EXHIBIT B

RECORDING REQUESTED BY AND WHEN RECORDED RETURN TO:
Berliner, Cohen & Biagini
99 Almaden Blvd., Suite 400
San Jose, CA 95113
Attn: Peggy L. Springgay, Esq.

      MEMORANDUM OF SUBLEASE, OPTION TO PURCHASE AND RIGHT OF FIRST REFUSAL

This  Memorandum  Of  Sublease,  Option to Purchase  and Right of First  Refusal
("Memorandum") is entered into by and between McDONNELL DOUGLAS  CORPORATION,  a
Maryland  corporation  ("Sublessor"),  and APPLE  COMPUTER,  INC.,  a California
corporation  ("Sublessee"),  with respect to a Sublease under that certain Lease
("Master  Lease") dated  January 6, 1978,  as amended by that certain  letter of
clarification,  dated  February 17,  1978;  Amendment,  dated  January 30, 1979;
Amendment  #2,  dated  March 17,  1979;  and  Amendment  #3,  dated July 1, 1987
(collectively  the "Master  Lease") by and between  JOHN A. SOBRATO and SUSAN R.
SOBRATO, as to an undivided forty-five percent (45%) interest,  CARL E. BERG and
MARY ANN BERG, as to an undivided  forty-five  percent (45%)  interest,  and ANN
RUSSO as to a ten percent (10%) interest, predecessor in interest of the current
lessor thereunder,  Carl E. Berg and Mary Ann Berg, as trustees on behalf of the
Berg Living Trust UTA,  dated May 1, 1981, as to an undivided  81.01%  interest,
Clyde Berg and Nancy Berg,  trustees of the Clyde Berg Living  Trust UTA,  dated
December 17, 1981, as to an undivided 11.83% interest,  and Clyde Berg,  trustee
of Carl Berg Child's  Trust UTA,  dated June 2, 1978,  as to an undivided  7.16%
interest ("Lessor"),  and TYMSHARE,  INC., predecessor in interest of Sublessor.
as lessee.

WHEREAS, Sublessor and Sublessee have entered into that certain Sublease dated ,
1987 (the "Sublease"), for the premises commonly known as 20605, 20665 and 20705
Valley  Green  Drive,  Cupertino,  California,  more  particularly  described in
Exhibit "A" attached hereto and incorporated herein ("Premises").

NOW, THEREFORE, Sublessor and Sublessee hereby state the following for recording
in the public records of Santa Clara County, California:

1. Sublessor  hereby  subleases to Sublessee and Sublessee hereby subleases from
Sublessor the Premises for an initial term of One-Hundred Twenty-two Months (122
months),  commencing  on  November 1, 1987  ("Commencement  Date"` and ending on
December 31, 1997.

2.  Subject  to the terms  and  conditions  of  Paragraph  4.2 of the  Sublease,
Sublessee  shall have the option to extend the term of the  Sublease for two (2)
successive five (5) year terms.

3.  Subject to the terms of the Master Lease and  Paragraph 22 of the  Sublease,
Sublessee  shall have the right of first  refusal to purchase the  Premises,  if
Sublessor receives notice from Lessor of Sublessor's right to exercise the right
of first  refusal  under the Master Lease on or before June 30. 1998. 4. Subject
to the terms of the Master Lease (including,  without limitation,  Paragraph 29)
which terms may cause the early termination of the option to purchase granted to
Sublessor  under the Master Lease and  Paragraph 21 of the  Sublease,  Sublessee
shall have the option to purchase the Premises,  which option to purchase may be
exercised  by  Sublessee no earlier than January 1, 1998 nor later than June 30.
1998.

5. This Memorandum shall  incorporate  herein all of the terms and provisions of
the Sublease as though fully set forth herein.

6. This  Memorandum is solely for recording  purposes and shall not be construed
to alter,  modify or  supplement  the  Sublease,  and has been  recorded to give
notice of the  existence of the  Sublease,  and the  Sublessee's  right of first
refusal  and option to  purchase  the  Premises.  If there is any  inconsistency
between this Memorandum and the Sublease, the Sublease shall prevail.

IN WITNESS  WHEREOF,  this  Memorandum  is executed on this __ day of _________,
1987.

SUBLESSOR:

McDONNELL DOUGLAS CORPORATION, a Maryland corporation

By
Its Vice Present Controller,
Network Systems Company, a division of Information Systems Group,
a division of McDonnell Douglas Corporation

Dated:

SUBLESSEE:

APPLE COMPUTER, INC., a California corporation

By
ALBERT A. EISENSTAT,
Senior Vice President

By
Secretary





                                      LEASE
                                 BY AND BETWEEN
                         DE ANZA BOULEVARD INVESTMENTS,
                 a limited partnership, and others, as Landlord

                                       and

                              APPLE COMPUTER, INC.,
                            a California corporation,
                                    as Tenant





                                TABLE OF CONTENTS


                                                               Page
                                                          
1.    PREMISES...................................................1
      1.1 Description............................................1
      1.2 Work of Improvement....................................1

2.    TERM.......................................................1
1
      2.1 Term...................................................1
      2.2 Options to Extend Lease Term...........................1

3.    RENT.......................................................2
      3.1 Base Monthly Rent......................................2
      3.2 Rental Adjustment......................................2
      3.3 Late Charge............................................2

4.    TAXATION...................................................2
      4.1 Real Property Taxes....................................2
      4.2 Personal Property Taxes................................3
      4.3 Assessments............................................3
      4.4 Right to Contest.......................................3

5.    USE........................................................3
      5.1 Use....................................................3
      5.2 Uses Prohibited........................................3

6.    UTILITIES AND WASTE DISPOSAL...............................4
      6.1 Utilities..............................................4
      6.2 Waste Disposal.........................................4
      6.3 Interference with Use of the Premises..................4

7.    MAINTENANCE, REPAIRS, AND ALTERATIONS......................4
      7.1 Landlord's Obligations.................................4
      7.2 Tenant's Obligations...................................4
      7.3 Leasehold Improvements.................................6

8.    ENTRY BY LANDLORD..........................................7

9.    LIENS......................................................7

10.   INDEMNITY..................................................8

11.   INSURANCE..................................................8
      11.1 Liability Insurance...................................8
      11.2 Property Insurance....................................9
      11.3 Waiver of Subrogation.................................9

12.   DAMAGE OR DESTRUCTION......................................9

13.   CONDEMNATION..............................................12
      13.1 Definition of Terms..................................12
      13.2 Rights...............................................12
      13.3 Total Taking.........................................12
      13.4 Partial Taking.......................................12

14.   ASSIGNMENT AND SUBLETTING.................................12

15.   SUBORDINATION.............................................14
      15.1 Subordination........................................14
      15.2 Subordination Agreements.............................15
      15.3 Quiet Enjoyment......................................15
      15.4 Attornment...........................................15

16.   DEFAULT; REMEDIES.........................................15
      16.1 Default..............................................15
      16.2 Remedies.............................................16
      16.3 Default by Landlord..................................16
      16.4 Tenant's Remedies....................................16

17.   BROKERAGE COMMISSIONS.....................................17

18.   HAZARDOUS MATERIALS.......................................17

19.   MISCELLANEOUS.............................................19
      19.1 Estoppel Certificate.................................19
      19.2 Transfer of Landlord's Interest......................19
      19.3 Captions; Attachments; Defined Terms.................19
      19.4 Entire Agreement.....................................19
      19.5 Severability.........................................20
      19.6 Costs of Suit........................................20
      19.7 Time; Joint and Several Liability....................20
      19.8 Binding Effect; Choice of Law........................20
      19.9 Waiver...............................................21
      19.10 Surrender of Premises...............................21
      19.11 Holding Over........................................21
      19.12 Reasonable Consent..................................21
      19.13 Recording...........................................21
      19.14 Notices.............................................21
      19.15 Authority...........................................21
      19.16 Appointment of Landlord's Agent.....................22
      19.17 Condition to Effectiveness of Lease.................22






                                 LEASE AGREEMENT
This Lease is dated March 24, 1989 for  reference  purposes  only and is made by
and between DE ANZA BOULEVARD INVESTMENTS, A LIMITED PARTNERSHIP and BERG & BERG
DEVELOPERS,   A  CALIFORNIA  PARTNERSHIP   (hereinafter  "Landlord")  and  APPLE
COMPUTER,  INC., a California  corporation  (hereinafter  "Tenant").  For and in
consideration of the rental and of the covenants and agreements  hereinafter set
forth to be kept and performed by Tenant,  Landlord  hereby leases to Tenant and
Tenant hereby leases from  Landlord the premises  hereinafter  described for the
term,  at the rental and  subject  to and upon all of the terms,  covenants  and
agreements hereinafter set forth.

1. PREMISES.

1.1  Description.  Landlord hereby leases to Tenant and Tenant hereby rents from
Landlord  those  certain  premises  (the  "Premises")  located  in the  City  of
Cupertino, County of Santa Clara, described and consisting of the following:

      A. That certain land and  building  sometimes  referred to as "De Anza 3",
      commonly  known as 10500 North De Anza  Boulevard,  and more  particularly
      described on the attached Exhibit "A", which building  contains a total of
      211,000 square feet of floor space (the "Building"); and

      B. The existing interior improvements and additional improvements that may
      be constructed in the Building by Tenant.

1.2 Work of Improvement.  Landlord shall deliver the Premises to Tenant in their
existing  condition.  Landlord  shall not be  required  to remodel or  otherwise
construct  any  improvements  or  make  any  alterations  to the  Premises.  Any
alterations,  additions or improvements  to the Premises  required or desired by
Tenant shall be constructed  by Tenant at its sole cost and expense,  subject to
the provisions of Section 7.3A.

2. TERM.

2.1 Term.  The term of this Lease (the "Lease Term") shall  commence on April 1,
1989 (the "Commencement Date"). The term of this Lease shall end eight (8) years
and two (2) months  following  the  Commencement  Date (i.e.,  on May 31, 1997),
unless sooner  terminated  pursuant to the provisions of this Lease, or extended
pursuant to the provisions of Section 2.2.

2.2  Options to Extend  Lease  Term.  Landlord  hereby  grants to Tenant two (2)
separate  options  to  extend  the  Lease  Term for five (5) years for each such
option on the following terms and conditions:

      A.  Tenant  must give  Landlord  notice in writing of its  exercise of the
      option in question no later than one hundred  eighty (180) days before the
      day the Lease Term would end but for said exercise.

      B. Tenant may not extend the Lease Term pursuant to any option  granted by
      this paragraph if Tenant is in material default as of the date of exercise
      of the option in question, as such defaults are defined in Section 16.

C. All terms and conditions of this Lease shall apply during each option period,
except that:  (i) the Base  Monthly  Rent for the first  option  period shall be
Three Hundred  Sixty-One  Thousand Five Hundred Seventy  Dollars  ($361,570) per
month, and (ii) the Base Monthly Rent for the second option period shall be Four
Hundred  Thirty-Three  Thousand Eight Hundred Eighty-Four Dollars ($433,884) per
month.

3. RENT.

3.1 Base Monthly Rent.  Beginning on the Commencement  Date and continuing until
May 31, 1989, Tenant shall pay to Landlord as Base Monthly Rent for the Premises
the sum of Two Hundred  Ninety-Five  Thousand Four Hundred  Thirty-Four  Dollars
($295,434)  per month.  Beginning on June 1, 1989,  and  continuing  through the
remainder of the Lease Term, Tenant shall pay to Landlord

                               - 1 -





as Base  Monthly  Rent  for the  Premises,  the sum of Two  Hundred  Ninety-Nine
Thousand Six Hundred Twenty Dollars ($299,620) per month,  subject,  however, to
adjustment  as  provided  in Section 3.2 and,  if one or both of the options to
extend are exercised,
Section 2.2C.

Base  Monthly  Rent shall be paid in  advance on the first day of each  calendar
month of the term of the  Lease,  without  deduction,  offset,  prior  notice or
demand,  in lawful money of the United States.  If the Commencement  Date is not
the first day of a month, or if the Lease  termination  date is not the last day
of a month,  a prorated Base Monthly Rent shall be paid at the then current rate
for the fractional month during which the Lease commences and/or terminates.

3.2 Rental  Adjustment.  The Base  Monthly  Rent shall be  increased  during the
initial Lease Term as follows:

      A. On the first day of the thirty-third  (33rd) full calendar month of the
      Lease Term,  the Base Monthly  Rent shall be  increased  to Three  Hundred
      Twelve Thousand Two Hundred Eighty Dollars ($312,280) per month.

      B. On the first day of the  sixty-third  (63rd) full calendar month of the
      Lease Term,  the Base Monthly  Rent shall be  increased  to Three  Hundred
      Twenty-Two Thousand Eight Hundred Thirty Dollars ($322,830) per month.

3.3 Late Charge.  Tenant acknowledges that late payment by Tenant to Landlord of
the Base Monthly Rent and other sums due hereunder  may cause  Landlord to incur
costs  not  contemplated  by this  Lease,  the  exact  amount  of which  will be
extremely  difficult to ascertain.  Such costs include,  but are not limited to,
processing  and  accounting  charges  and late  charges  which may be imposed on
Landlord by the terms of any mortgage or deed of trust  covering  the  Premises.
Accordingly,  in the event Tenant fails to pay any  installment  of Base Monthly
Rent  and/or  other sums due  hereunder  within ten (10) days after said rent or
other  sum is due,  Tenant  shall pay to  Landlord  a late  charge  equal to two
percent (2%) of such  overdue  amount.  The parties  agree that such late charge
represents a fair and  reasonable  estimate of the cost  Landlord  will incur by
reason of late payment by Tenant.

4. TAXATION.

4.1 Real Property Taxes. Tenant shall pay prior to delinquency all real property
taxes which, during the term of this Lease, are levied, assessed or imposed upon
or against the  Premises.  In the event any such real  property  taxes cover any
period of time prior to commencement or after the expiration of the term of this
Lease,  Tenant's  obligation  to pay such taxes shall be  equitably  prorated to
cover only the period of time within the fiscal tax year during  which the Lease
is in effect.

As used in this Lease,  the term "real  property  tax" shall include any form of
assessment, levy, penalty or tax (other than inheritance,  estate, net income or
franchise  taxes) imposed by any authority  having the power to tax,  including,
without limitation, any tax:

      A. Upon, allocable to, or measured by the Premises or the
      rental payable hereunder; or

      B. Upon or with respect to the possession, leasing,
      operation, management, maintenance, alteration, repair, use
      or occupancy by Tenant of the Premises or any portion
      thereof; or

      C. Upon or measured by the value of Tenant's personal
      property, equipment or fixtures located in the Premises; or

      D.  Upon  this  transaction  or any  document  to which  Tenant is a party
      creating or transferring an interest or an estate in the Premises.

      E. Tenant  acknowledges  that it is responsible  for any increase in taxes
      due to a transfer of Landlord's interest in the Premises.


                               - 2 -





4.2 Personal  Property  Taxes.  Tenant shall pay prior to delinquency  all taxes
assessed against and levied upon trade fixtures, furnishings,  equipment and all
other personal property of Tenant located in the Premises.

4.3  Assessments.  If any  assessments are levied against the Premises after the
date hereof and Landlord has the option to either pay the  assessment in full or
allow the assessment to go to bond and to pay it in installments, Landlord shall
cause the assessment to go to bond and be paid in  installments of principal and
interest.  Tenant shall pay as its share of each such installment  which becomes
due during the Lease Term, an amount based upon the ratio of the square  footage
of  the  Premises  to the  square  footage  of  the  property  covered  by  such
assessment,  or such other  equitable basis as agreed to by Landlord and Tenant,
provided  if the taxing  authority  requires a lump sum  payment of such  bonded
assessment during the Lease Term, Tenant shall pay such payment when due.

4.4  Right to  Contest.  If  Landlord  receives  any  notice  of  assessment  or
reassessment  in excess of five  percent (5%) more than the  assessment  for the
prior period,  or notice of any imposition of new real property taxes,  Landlord
shall provide  Tenant with a copy of such notice within  fifteen (15) days after
Landlord's receipt thereof. In the event Tenant desires in good faith to contest
or otherwise  review by  appropriate  legal or  administrative  proceedings  the
imposition of any such real property tax,  Tenant shall,  at least ten (10) days
prior to the delinquency of such real property tax, give Landlord written notice
of its intention to do so. Tenant may withhold  payment of the real property tax
being  contested if (i)  non-payment  is  permitted  during the pendency of such
proceedings  without the  foreclosure  of any tax lien or the  imposition of any
fine or penalty,  and (ii) if required by any  beneficiary of a deed of trust of
Landlord's interest in the Premises, or purchaser of Landlord's interest, Tenant
shall furnish Landlord with a bond sufficient to protect Landlord's  Interest in
the Premises.  Any such contest  shall be conducted  without delay and solely at
Tenant's  expense.  Tenant shall protect and indemnify  Landlord against any and
all expenses or damages resulting from such contest of other proceeding.  At the
request of Tenant, Landlord shall join in any contest or other proceedings which
Tenant may desire to bring  pursuant to this  Section.  Tenant  shall pay all of
Landlord's expenses arising out of such joinder.  Within ten (10) days after the
final  determination  of the amount  due from  Tenant  with  respect to the real
property tax  contested,  Tenant shall pay the amount so  determined  to be due,
together with all costs, expenses and interest,  whether or not this Lease shall
have then expired or terminated.

5. USE.

5.1 Use.  The  Premises  shall  be used  and  occupied  by  Tenant  for only the
following  purposes and for no other purpose  whatsoever  without  obtaining the
prior  written  consent of  Landlord:  office,  light  warehouse,  distribution,
engineering,  research and development, product testing, incidental training and
any other  legal uses for  Tenant's  business as the same may exist from time to
time. This Lease shall be subject to all applicable zoning ordinances and to any
municipal,  county and state laws and  regulations  governing and regulating the
use of the Premises.

5.2 Uses Prohibited.

     A.  Tenant  shall  not do or  permit  anything  to be done in or about  the
     Premises  which will  increase  the  existing  rate of  insurance  upon the
     Premises (unless Tenant shall pay any increased premium as a result of such
     use or acts) or cause the cancellation of any insurance policy covering the
     Premises,  nor shall  Tenant sell or permit to be kept,  used or sold in or
     upon the Premises,  any articles which may be prohibited by a standard form
     policy of fire insurance.

     B. Tenant shall not allow the Premises to be used for any unlawful  purpose
     nor shall  Tenant  cause,  maintain  or permit any  nuisance in or upon the
     Premises. Tenant shall not commit or suffer to be committed any waste in or
     upon the Premises and Tenant shall keep the Premises in a clean condition.

     C. Tenant shall not use the Premises, or permit anything to
     be in or about the Premises which will violate any Laws now
     in force or which may
                               - 3 -





      hereafter be enacted or promulgated.  Subject to the provisions of Section
      7.3,  Tenant shall at its sole cost and expense  promptly  comply with all
      Laws now in  force  or which  may  hereafter  be in force  relating  to or
      affecting the condition, use or occupancy of the Premises. The judgment of
      any court of  competent  jurisdiction  or the  admission  of Tenant in any
      action against  Tenant,  whether  Landlord is a party thereto or not, that
      Tenant has violated any Laws shall be  conclusive  of that fact as between
      Landlord and Tenant. Tenant shall have the right at its expense to contest
      the application to it or the Premises of any Laws and to defer  compliance
      during the pendency of such  contest so long as Landlord is not  subjected
      to any civil or criminal liability by reason of Tenant's noncompliance.

6. UTILITIES AND WASTE DISPOSAL.

6.1 Utilities.  Commencing on the Commencement  Date,  Tenant shall pay prior to
delinquency,  for all water, gas, heat, light,  power,  telephone,  sewage,  air
conditioning and ventilating, scavenger, Janitorial, and all other materials and
utilities supplied to the Premises and all taxes and surcharges thereon.

6.2 Waste  Disposal.  Tenant shall store its waste either inside the Premises or
in its own dumpsters located outside the Premises.

6.3  Interference  with  Use  of  the  Premises.  In  the  event  of a  material
interference  with Tenant's use of the leased  Premises as a consequence  of the
cessation  of  utility  service  caused  by  the  gross  negligence  or  willful
misconduct of Landlord or its agents, contractors, employees or invitees, Tenant
shall be  entitled to an  abatement  of Base  Monthly  Rent to the extent of the
interference  with  Tenant's use of the leased  Premises,  if such  cessation of
utility service and consequent material  interference  persists for a continuous
period of two (2)  business  days or more.  Any  abatement  of Base Monthly Rent
shall  commence with the first business day after the beginning of the cessation
of utility  service  and shall  continue  until  that date on which the  utility
service is restored.

7. MAINTENANCE. REPAIRS. AND ALTERATIONS.

7.1 Landlord's  Obligations.  Subject to the provisions of Section 12 and except
for damage caused by the negligence,  omission, or intentional act of Tenant and
Tenant's agents,  employees or invitees, which damage is not covered by the type
of insurance to be  maintained  pursuant to Section 11.2 hereof,  Landlord,  at
Landlord's  expense,  shall  keep  in  good  order,  condition  and  repair  the
foundation, building structure, and load-bearing walls of the Premises. Landlord
shall  have no  obligation  to make  repairs  under  this  Section 7.1  until a
reasonable  time after  receipt of written  notice of the need for such repairs.
If, within thirty (30) days after notice from Tenant, Landlord fails to commence
making  repairs which are the  obligation of Landlord under this Section 7.1 and
diligently  prosecute  such work to  completion,  Tenant shall have the right to
make such repairs and charge Landlord for the reasonable  cost thereof.  In such
event,  Landlord  shall  reimburse  Tenant for the cost of such  repairs  within
thirty (30) days after demand from Tenant with interest at ten percent (10%) per
annum from the date of such work.

7.2 Tenant's Obligations.

A.  Subject to the  provisions  of  Sections 12 and 7.1,  Tenant,  at  Tenant's
expense,  shall  maintain in good order,  condition  and repair the Premises and
every part  thereof,  including  but not limited to floors,  ceilings,  windows,
doors,  skylights,   roofing,   interior  walls,  the  plumbing,   heating,  air
conditioning and ventilating  equipment,  electrical and lighting facilities and
equipment  to  the  Premises  including  exterior  lighting,  parking  lot,  and
landscaping.  Said  maintenance  shall  include,  without  limitation,  periodic
service to the HVAC  equipment  and elevators by qualified  personnel.  If items
Tenant is  required to  maintain  cease to  reasonably  function,  Tenant  shall
replace such worn out items.

B. All glass, both interior and exterior, is at the sole risk of Tenant; and any
broken glass shall promptly be replaced by Tenant at Tenant's expense with glass
of the same kind, size and quality according to the current local code.

                               - 4 -





C. Upon the  expiration  or earlier  termination  of this  Lease,  Tenant  shall
surrender the Premises in the same condition as received,  broom clean, ordinary
wear and tear alone excepted.  Tenant,  at its sole cost and expense,  agrees to
repair any damage to the Premises caused by or in connection with the removal of
any  articles  of personal  property,  business  or trade  fixtures,  machinery,
equipment or furniture.  The  obligations of Landlord and Tenant  concerning the
following subjects are governed  exclusively by the indicated Sections,  and the
parties do not intend the  immediately  preceding  two  sentences  to modify the
obligations  of the  parties  with  respect  to  these  subjects:  (i)  Tenant's
obligation to remove leasehold improvements,  which is governed by Section 7.3A;
(ii) the repair and restoration of the Premises  following  damage caused by any
peril, which is governed by Section 12; (iii) repair of the Premises following a
condemnation,  which is governed by Section 13; and (iv) the  obligations of the
party with respect to the  investigation  and  remediation of  contamination  by
Hazardous Materials, which is governed by Section 18.

D. In the event Tenant fails to perform Tenant's  obligations under this Section
7, Landlord  shall give Tenant  written notice to do such acts as are reasonably
required to maintain the Premises. If, within thirty (30) days after notice from
Landlord,  Tenant  fails to commence  the work and  diligently  prosecute  it to
completion,  then Landlord  shall have the right (but not the  obligation) to do
such acts and  expend  such  funds at the  expense  of Tenant as are  reasonably
required to perform such work.  Any amount so expended by Landlord shall be paid
by Tenant  within  thirty (30) days after  demand  with  interest at ten percent
(10%) per annum form the date of such work.

E. Tenant shall have the benefit of all  warranties  available to Landlord which
would  reduce the cost of  performing  the  obligations  of Tenant  pursuant  to
Section 7.2,  and  Landlord  shall  cooperate  with Tenant in  enforcing  these
warranties.  Tenant  shall not be  responsible  for the cost of  maintenance  or
repair to the Premises or any portion thereof to the extent such  maintenance or
repair is necessary as a result of the gross negligent act or willful misconduct
of Landlord or its agents, employees, contractors or invitees.

F. If Tenant becomes obligated pursuant to Section 7.2 (A) to perform during the
last  three (3) years of the  initial  Lease  Term (or during the last three (3)
years of any option period) any item of repair or replacement to any part of the
Premises  and the cost of  repair or  replacement  of that item is more than One
Hundred  Thousand  Dollars  ($100,000),  then the cost of such item of repair or
replacement shall be shared as follows:

      (i) Tenant shall pay the first One Hundred Thousand Dollars  ($100,000) of
      the cost of such item of repair or replacement, and Landlord shall pay the
      balance of such cost ("Landlord's Contribution").

      (ii) Landlord's Contribution shall be amortized over a period equal to the
      lesser of  fifteen  (15)  years or the  functional  life of the  repair or
      replacement in question,  with interest on the unamortized  balance at the
      then  prevailing  market rate Landlord  would pay if it borrowed  funds to
      permanently finance the cost of such item of repair or replacement from an
      institutional lender following completion. Landlord shall notify Tenant of
      its determination of the appropriate  amortization schedule based upon the
      foregoing,  and the  monthly  amortization  payment  that  must be paid to
      amortize  Landlord's  Contribution,  and  shall  provide  Tenant  with the
      information  upon which such  determination  is made.  Such  determination
      shall be subject to the  approval of Tenant.  Tenant shall pay in addition
      to the Base  Monthly  Rent an amount  equal to such  monthly  amortization
      payment  for each  month  after  such  item of repair  or  replacement  is
      completed  during the  remainder of the initial term of this Lease and any
      extension of the Lease Term  resulting  from the exercise of any option to
      extend pursuant to Section 2.2.

G. Immediately  prior to Lease termination  Tenant shall either:  (i) furnish to
Landlord  certifications from licensed reputable contractors that the elevators,
HVAC systems and roof of the Premises  are in good  working  condition;  or (ii)
shall place the elevators, HVAC systems and roof in such good condition.

                               - 5 -





7.3 Leasehold Improvements.
A. Tenant shall not construct any leasehold  improvements or otherwise alter the
leased  Premises  without  Landlord's  prior  written  approval of the plans and
specifications  therefor,  which approval shall not be unreasonably  withheld or
delayed;  provided,  however,  that Tenant shall have the right to make interior
alterations  to the  Premises  which do not  materially  affect  the  structural
elements  of the  Premises  and  do  not  exceed  Twenty-Five  Thousand  Dollars
($25,000) in cost, without obtaining Landlord's prior written approval. All such
leasehold  improvements  shall be installed  by Tenant at Tenant's  expense by a
licensed  contractor in compliance  with the approved  plans and  specifications
therefor and in strict accordance with all Laws. All such construction  shall be
done in a good and  workmanlike  manner  using new  materials  of good  quality.
Tenant shall not commence  construction of any leasehold  improvements until (i)
all required  governmental  approvals and permits shall have been obtained;  and
(ii)  Tenant  shall have  given  Landlord  at least five (5) days prior  written
notice  of  its   intention  to  commence  such   construction.   All  leasehold
improvements  constructed  by Tenant shall remain the property of Tenant  during
the Lease Term and Tenant shall have the right to depreciate  the same and claim
and  collect  investment  tax credits  and all other tax  savings  with  respect
thereto.  Tenant  shall  have the right to  remove  any  leasehold  improvements
installed  by Tenant so long as (i) it repairs all damage  caused by the removal
thereof  and  returns  the  Premises  to the  condition  existing  prior  to the
installation;  and (ii)  such  improvements  are not  integrated  into  building
systems  such as HVAC or  electrical  systems.  Landlord  may require  Tenant to
remove at the  expiration of the Lease Term  leasehold  improvements  previously
designated  by  Landlord  and restore the  Premises to the extent  necessary  to
return the  Premises to a  condition  that has  substantially  the same value as
existed on the Commencement Date,  ordinary wear and tear excepted,  if (a) such
improvements were approved in writing by Landlord; (b) at the time such approval
was given by Landlord,  Landlord  informed Tenant in writing that Landlord would
require that such leasehold  improvements  be removed at the  termination of the
Lease Term; and (c) such improvements are of limited special purpose use and are
not commonly  installed in buildings of the size,  quality and type,  and in the
location of the  Premises.  Subject to the  provisions of phrases (a) and (b) of
the preceding  sentence,  Landlord may require Tenant to remove  standard office
improvements  at the  expiration  of the  Lease  Term if more  than  twenty-five
percent  (25%) of the gross  square  footage of the Premises is used for private
offices,  but in no event  shall  Tenant  be  obligated  to remove  more  office
improvements  than are required to reduce the space within the Premises used for
private offices to twenty-five  percent (25%) of the gross square footage of the
Premises.

Within ten (10) business days after demand therefor from Tenant,  Landlord shall
execute and deliver a lien waiver or other document in form customarily required
by any supplier,  lessor or lender in connection  with the  installation  in the
Premises of Tenant's personal property, equipment or trade fixtures, pursuant to
which Landlord shall waive any right it may have or acquire with respect to such
property.  Such  waiver may  require  Landlord  to grant to the party  requiring
Tenant to  obtain  such  waiver,  a license  to enter the  Premises  in order to
assemble,  inventory or remove the property covered by the lien waiver, provided
Tenant is not in default and  provided  that the entry and  removal  takes place
during the Lease Term and such third party shall  repair in a first class manner
any and all damage caused by removal of specific property.

B.  Alterations  Required  by Law.  Tenant  shall,  at its sole  cost,  make any
alteration,  addition or change of any sort, whether structural or otherwise, to
the Premises  that is required by Laws  because of (i) Tenant's  specific use or
change of use of the Premises,  or (2) Tenant's  construction or installation of
any leasehold improvements or trade fixtures.

C. Right to Contest. In the event Tenant is required by any Laws and pursuant to
Section 7.3(B) to make any capital  improvement  to the Premises,  Tenant shall
have  the  right  to  contest  or  otherwise  review  by  appropriate  legal  or
administrative proceedings the application of such Laws. If Tenant desires to so
contest or cause the review of such Laws,  Tenant  shall give  Landlord  written
notice of its intention to do so and may conduct such contest or other review so
long as it pays all costs, and compliance therewith may be held

                               - 6 -





in  abeyance  pending  completion  of  such  proceedings.  If  required  by  any
beneficiary  of a deed of  trust  of  Landlord's  interest  in the  Premises  or
purchaser of Landlord's interest,  Tenant shall obtain and furnish Landlord with
an appropriate bond or other security reasonably  sufficient to protect Landlord
from  Tenant's  failure to comply  with such Laws  during the  pendency  of such
proceedings.  Tenant shall  protect and indemnify  Landlord  against any and all
expenses or damages resulting from such contest or other proceeding.

D. Other Required Capital  Improvements.  If any capital improvement  (including
structural  modifications  to the foundation,  load bearing walls,  and building
structure)  is required  to be made to the  Premises in order to comply with any
Laws and if Tenant is not obligated to make such capital improvement pursuant to
Section 7.3(B), then the following shall apply:

      (i) Landlord shall construct such capital improvement at its sole cost and
      expense in accordance with the applicable Laws.

      (ii) All  reasonable  costs paid by Landlord to  construct  such  required
      capital  improvement  (including  financing costs) shall be amortized over
      the functional life of such  improvement or fifteen (15) years,  whichever
      is less, with interest on the  unamortized  balance at the then prevailing
      market rate Landlord would pay if it borrowed funds to permanently finance
      such  improvement  from  an  institutional  lender  following  completion.
      Landlord  shall  notify  Tenant of its  determination  of the  appropriate
      amortization   schedule   based  upon  the   foregoing   and  the  monthly
      amortization  payment that must be made to amortize such costs,  and shall
      provide Tenant with the information upon which such determination is made.
      Such determination shall be subject to the approval of Tenant. In addition
      to the Base Monthly Rent, Tenant shall pay an amount equal to such monthly
      amortization  payment for each month  after such  capital  improvement  is
      completed  during the  remainder of the initial term of this Lease and any
      extension of the Lease Term  resulting  from the exercise of any option to
      extend pursuant to Section 2.2.

8. ENTRY BY  LANDLORD.  Landlord and  Landlord's  agents shall have the right at
reasonable times and upon reasonable  written notice to Tenant, of not less then
twenty-four (24) hours, except in an emergency, and subject to Tenant's security
requirements,  to enter the  Premises  to inspect  the same or to  maintain  and
repair, make alterations or additions to the Premises or any portion thereof, to
the extent  permitted  or  required by this  Lease,  or to show the  Premises to
prospective  purchasers  and lenders  or,  during the last six (6) months of the
Lease Term, to prospective tenants. Any entry by Landlord or its agents shall be
done in a manner to minimize interference with Tenant's use of the Premises.

9. LIENS. Tenant shall keep the Premises free from any liens arising out of work
performed,  materials  furnished  or  obligations  incurred  by Tenant and shall
indemnify,  hold harmless and defend  Landlord  from any liens and  encumbrances
arising out of any work performed or materials  furnished by or at the direction
of  Tenant.  Tenant  shall  have the right to  contest  the  correctness  or the
validity of any such lien if it provides assurances  reasonably  satisfactory to
Landlord that Landlord will suffer no financial  detriment as the result of such
contest; provided,  however, that Tenant shall cause such lien to be released in
the event it is  necessary  for  Landlord  to cause such lien to be  released in
connection  with any sale or financing  of the Premises  that is to occur during
the pendency of such contest. Landlord shall have the right at all times to post
and keep posted on the  Premises  any notices  permitted  or required by law, or
which  Landlord  shall deem  proper,  for the  protection  of  Landlord  and the
Premises,  and any other party having an interest  therein,  from mechanics' and
material persons' liens and Tenant shall give to Landlord at least five (5) days
prior written notice of the expected date of  commencement  of any work relating
to alterations or additions to the Premises.

10.  INDEMNITY.  Tenant shall  indemnify  and hold  Landlord  harmless  from and
against any and all claims of  liability  for any injury or damage to any person
or property  arising from Tenant's use of the  Premises,  or from the conduct of
Tenant's  business,  or from any  activity,  work or thing  done,  permitted  or
suffered by Tenant in or upon the Premises.  Tenant shall further  indemnify and
hold Landlord harmless from and against any and all claims arising from any

                               - 7 -





breach or default in the  performance  of any  obligation on Tenant's part to be
performed under this Lease by Tenant or Tenant's agents, contractors,  invitees,
or employees, including Tenant's failure to carry the insurance required by this
Lease, and from and against all costs, attorneys' fees, expenses and liabilities
incurred in the defense of any such claim,  or any action or proceeding  brought
thereon.  In the event any action or proceeding is brought  against  Landlord by
reason of such claim,  Tenant upon notice from Landlord shall defend the same at
Tenant's expense with an attorney reasonably acceptable to Landlord.

Notwithstanding  anything to the contrary in this Lease,  Tenant  shall  neither
release  Landlord  from,  nor indemnify  Landlord with respect to: (i) the gross
negligence  or  willful  misconduct  of  Landlord,  or  its  agents,  employees,
contractors or invitees; or (ii) a material breach of Landlord's  obligations or
representations  under this Lease.  Landlord  shall  indemnify and hold harmless
Tenant from all  damages,  liabilities,  judgments,  actions,  attorneys'  fees,
consultants'  fees,  costs and  expenses  arising from the gross  negligence  or
willful  misconduct  of  Landlord  or its  employees,  agents,  contractors,  or
invitees,  or the material breach of Landlord's  obligations or  representations
under this Lease.

Nothing in this Section 10 is intended to modify the provisions of Section 11.3,
and in the event  this  Section 10 is  determined  to be  inconsistent  with the
provisions of Section 11.3, the provisions of Section 11.3 shall prevail.

11. INSURANCE.

11.1 Liability  Insurance.  Tenant shall,  at its own expense,  maintain in full
force and effect  during the Lease Term a policy or  policies  of  comprehensive
general liability insurance, including property damage carried with a company or
companies  reasonably  satisfactory  to Landlord,  which will insure  Tenant and
Landlord against liability for personal injury, bodily injury, death, and damage
to property occurring in or about, or resulting from any occurrence in or about,
the Premises with combined  single limit  coverage of not less than Five Million
Dollars  ($5,000,000).  Such comprehensive  general liability insurance shall be
extended  to  include  "blanket  contractual   liability"  endorsement  insuring
Tenant's  performance of Tenant's  obligation to indemnify Landlord contained in
Section 10 and all of the other broadened  liability features normally contained
in an extended  liability  endorsement.  The limits of such insurance  shall not
limit the liability of Tenant.  Tenant shall deliver to Landlord certificates of
insurance,  endorsements  stating Tenant's insurance is primary,  evidencing the
existence  and amounts of such  insurance  and naming  Landlord as an additional
insured.  In the event  Tenant  fails to procure and  maintain  such  insurance,
Landlord may (but shall not be required to) procure the same at Tenant's expense
after thirty (30) days prior written notice.  No such policy shall be cancelable
or subject to  reduction of coverage or other  modification  except after thirty
(30) days prior  written  notice to Landlord by the insurer.  All such  policies
shall be written as primary policies, not contributing with and not in excess of
coverage which Landlord may carry. Tenant shall, prior to the expiration of such
policies, furnish Landlord with renewals or binders. Tenant shall have the right
to provide such  insurance  coverage  pursuant to blanket  policies  obtained by
Tenant provided such blanket policies  expressly afford coverage to the Premises
and to Landlord as required by this Lease.  Landlord shall maintain, at its sole
cost and  expense,  a policy or  policies  of  comprehensive  general  liability
insurance  insuring  Landlord  (and such others as are  designated  by Landlord)
against  liability for personal  injury,  bodily  injury,  death,  and damage to
property occurring or resulting from an occurrence in, on or about the Premises,
with  combined  single  limit  coverage  of not less than Five  Million  Dollars
($5,000,000),  or such  greater  coverage  as  Landlord  may  from  time to time
determine is reasonably necessary for its protection.

11.2 Property Insurance. Tenant shall, at Tenant's expense, procure and maintain
at all times  during the term of this Lease a policy or  policies  of  insurance
covering  loss or damage to the  Premises in the amount of the full  replacement
value  thereof and loss of rental  income (for a maximum of twelve (12)  months)
thereof,   providing   protection   against  all  perils   included  within  the
classification  of  fire,  extended  coverage,  vandalism,  malicious  mischief,
sprinkler leakage and special extended peril (all-risk). Tenant shall not be

                               - 8 -





obligated to carry earthquake  insurance unless it becomes Tenant's  practice to
maintain such insurance for a majority of all  multi-story  buildings  leased or
owned by  Tenant  in the Bay Area and  containing  80,000  square  feet or more.
Tenant shall deliver to Landlord certificates of insurance, endorsements stating
Tenant's  insurance is primary,  evidencing  the  existence  and amounts of such
insurance  and naming  Landlord as an  additional  insured.  In the event Tenant
fails to procure and  maintain  such  insurance,  Landlord may (but shall not be
required to) procure the same at Tenant's  expense  after thirty (30) days prior
written  notice.  No such policy shall be  cancelable or subject to reduction of
coverage or other  modification  except  after  thirty  (30) days prior  written
notice to Landlord by the insurer. All such policies shall be written as primary
policies, not contributing with and not in excess of coverage which Landlord may
carry. Tenant shall, prior to the expiration of such policies,  furnish Landlord
with renewals or binders.  Tenant shall have the right to provide such insurance
coverage  pursuant to blanket policies  obtained by Tenant provided such blanket
policies  expressly  afford coverage to the Premises and to Landlord as required
by this Lease.

11.3 Waiver of  Subrogation.  Landlord  and Tenant each hereby waive any and all
rights of recovery  against  the other,  and  against  the  officers,  partners,
employees, agents and representatives of the other, on account of loss or damage
to such waiving party's  property or the property of others under its control to
the  extent  that  such  injury,  loss or damage is  insured  against  under any
insurance  policy  in force at the time of such  loss or  damage.  Landlord  and
Tenant agree to notify the insurance  carrier or carriers  under any such policy
that the  foregoing  mutual  waiver of  subrogation  is contained in this Lease.
Landlord and Tenant will each cause its respective insurers to issue a waiver of
subrogation  rights  endorsement  to each policy of insurance  in question,  and
Landlord and Tenant shall each provide the other with  evidence that such waiver
has been obtained within a reasonable period of time.

12. DAMAGE OR DESTRUCTION.

A. If the Premises are damaged by any peril,  then  Landlord  shall  restore the
damage, except if this Lease is terminated pursuant to Section 12B, Section 12C,
or Section 12G hereof. All proceeds of the insurance carried pursuant to Section
11.2 shall be paid to Landlord.  The proceeds shall be used for the  restoration
of the damage, if the Lease is not terminated. Notwithstanding the foregoing, in
the event Landlord is not the original Landlord named herein or a partnership in
which one of the general partners is Carl E. Berg or a partnership of which Carl
E. Berg is the general  partner,  and the Premises are to be restored,  then the
insurance  proceeds shall be deposited with any  institutional  lender holding a
mortgage  or deed of trust  against  the  Premises  or if none,  then such other
institutional  lender as agreed to by Landlord and Tenant,  for  disbursement of
such funds for the purpose of  restoration.  As used herein,  an  "institutional
lender" shall mean a bank,  savings and loan association,  or insurance company.
Upon receipt (or deposit) of such insurance  proceeds,  if  applicable,  and the
issuance of all necessary  governmental  approvals,  Landlord shall commence and
diligently   prosecute  to  completion  the   restoration  of  the  Premises  to
substantially  the same  condition  existing  immediately  prior to such damage,
using the  insurance  proceeds.  Landlord  shall be  responsible  for paying any
"deductible" amount that is excluded from earthquake  insurance coverage,  up to
Four Hundred Eighty Thousand Dollars  ($480,000);  provided,  however,  that any
such earthquake  "deductible"  paid by Landlord shall be amortized over a period
equal to the  remainder of the initial  Lease Term and all  remaining  extension
periods  pursuant to Section 2.2 (whether or not exercised) with interest on the
unamortized  balance at the then  prevailing  market rate Landlord would pay for
borrowed funds to permanently  finance such  restoration  from an  institutional
lender, and Tenant shall pay as additional monthly rent such amortization during
the  remainder of the initial term of this Lease and any  extension of the Lease
Term  resulting  from the  exercise of any option to extend  pursuant to Section
2.2. If Tenant becomes  obligated to pay such amortization and does not exercise
all of its options to extend the Lease Term  pursuant to Section 2.2,  then upon
the  expiration  of the  Lease  Term,  Tenant  shall pay a lump sum  payment  to
Landlord equal to the unamortized  principal balance of the amount that is being
so amortized.  Tenant shall be responsible  for paying any  "deductible"  amount
that is excluded from any other type of insurance coverage.

                              - 36 -





B. In the event the Premises are damaged by any peril, whether or not covered by
the  insurance  carried  pursuant to Section 11.2,  during the last year of the
Lease Term (as it may be extended) to such an extent that the estimated  cost to
restore exceeds Five Hundred  Thousand Dollars  ($500,000),  then Landlord shall
have the  option to  terminate  this  Lease by  delivery  to Tenant of a written
notice of  election  to  terminate  within  thirty  (30) days after the date the
damage occurs. Notwithstanding the foregoing, Landlord may not so terminate this
Lease  pursuant to this  Section 12B if (i) Tenant,  at the time of such damage,
has an unexercised  option to further extend the Lease Term and Tenant exercises
such  option to so  further  extend  the Lease  Term  within  fifteen  (15) days
following  Landlord's exercise of its option to terminate and (ii) Tenant agrees
in writing as provided in Section 12G that in the event  Landlord  does not for
any reason receive sufficient funds from insurance proceeds or Tenant to restore
the Premises that the amount of such insufficiency shall be amortized and Tenant
shall pay as additional rent such amortization in the manner provided in Section
12G.

C. If the  Premises  are  damaged  by any peril and  Landlord  does not elect to
terminate this Lease or is not entitled to terminate this Lease pursuant to this
Section 12,  then as soon as  reasonably  practicable,  Landlord  shall  furnish
Tenant  with  the  written  opinion  of  Landlord's  architect  or  construction
consultant as to when the restoration work required of Landlord may be completed
and the estimated cost of such restoration work. Tenant shall have the following
options to  terminate  this Lease,  which may be  exercised  only by delivery to
Landlord of a written  notice of election to terminate  within fifteen (15) days
after Tenant  receives from Landlord the estimate of the time needed to complete
such restoration:

      (i) Tenant may terminate this Lease if the Premises are damaged by a peril
      (whether or not covered by the insurance  required to be carried  pursuant
      to Section 11.2)  during the last year of the Lease Term and such  damage
      cannot be  substantially  restored  within ninety (90) days  following the
      date of such damage.

      (ii) Tenant may terminate this Lease in the event the Premises are damaged
      by any peril  (whether  or not  covered by the  insurance  required  to be
      carried pursuant to Section 11.2) and the restoration  cannot be completed
      by Landlord  within one hundred  eighty  (180) days after the date of such
      damage.

D. If this Lease is terminated by the proper  exercise of an option to terminate
granted to Landlord or Tenant by this Lease, then (i) this Lease shall terminate
fifteen (15) days after the date the option to terminate is properly  exercised,
(ii) the Base Monthly Rent and all other charges due hereunder shall be prorated
as of the date of termination,  (iii) Landlord shall be entitled to all proceeds
payable under any insurance  including loss of rental  income,  and (iv) neither
Landlord  nor Tenant  shall have any further  rights or  obligations  under this
Lease  except  for those  that have  accrued  prior to the date of  termination,
subject to the survival of the  indemnities  contained in Section 10 and Section
18.

E. Landlord's  obligation (should it elect or be obligated to repair or rebuild)
shall be limited to the  following:  (i) the  structural  parts of the Building;
(ii) all building service equipment and utility systems;  and (iii) all interior
walls, light fixtures, floor and wall coverings, and other interior improvements
(excluding  Tenant's  trade  fixtures,  business  equipment  and other  personal
property) to substantially  the same extent of the level and quality of interior
improvement as existed as of the Commencement  Date but in the  configuration of
such interior  improvements as existed on the date of such damage. If Tenant has
installed  leasehold  improvements  which  increase  the  level and  quality  of
interior improvement to the Premises over and above that which existed as of the
Commencement  Date,  Tenant shall be  responsible  for the  restoration  of such
higher level of interior  improvement.  Notwithstanding  the  foregoing:  (i) if
Tenant has during the Lease Term installed permanent  partitions  resulting in a
higher percentage of the floor area of the Premises being devoted to offices and
conference rooms than existed as of the Commencement  Date, Tenant shall only be
obligated  to  restore  the  Premises  so that  it has  substantially  the  same
percentage of floor area devoted to offices and  conference  rooms as existed as
of the Commencement Date; and (ii) if the level of finishes

                              - 10 -





existing prior to the damage was of a substantially higher level of quality than
are customarily installed in comparable space in Cupertino, Tenant shall only be
obligated to restore the  Premises to that level of finish as is  customary  for
comparable  space in  Cupertino,  but in no event to a quality of finish that is
lower  than  existed  as of the  Commencement  Date.  Tenant  shall  pay for and
complete the replacement or repair of its trade fixtures, business equipment and
personal  property  to the  extent  necessary  for the  continued  operation  of
Tenant's business in the Premises. Subject to the provisions of Section 12A, all
insurance  shall be made  available  to Landlord to permit it to  discharge  its
obligations under this Lease regarding restoration;  provided,  however, that in
the event of restoration  only Tenant shall receive  proceeds  payable under the
insurance  carried  pursuant to Section 11.2 that are fairly  allocable  to the
leasehold  improvements  installed  at the expense of Tenant,  to the extent any
proceeds  remain after deducting that portion  attributable to the  improvements
Landlord is  obligated  to repair or rebuild in  accordance  with the  foregoing
(including  any  improvements  Tenant made which are  integrated  into  building
systems such as HVAC or electrical).

F. In the  event of any  damage  to the  Premises  which  does not  result  in a
termination  of this  Lease,  the Base  Monthly  Rent  and  other  sums  payable
hereunder shall be temporarily abated  proportionately  with the degree to which
Tenant's use of the Premises is impaired by such damage (based upon the ratio of
Building area rendered unusable to the total Building area), commencing from the
date of such damage or destruction and continuing  during the period required by
Landlord to complete its  restoration of the Premises.  However,  such abatement
shall  occur only to the extent of the  proceeds of rental  abatement  insurance
actually recovered by Landlord.

G. In the event the Premises  are damaged by a peril and  Landlord  does not for
any reason receive sufficient funds from insurance proceeds or Tenant to restore
the Premises as required by this Section 12, then  Landlord may  terminate  this
Lease; provided, however, that if insurance proceeds are insufficient to restore
the Premises  because of a  "deductible"  amount that is excluded from insurance
coverage and such "deductible"  amount is less than Four Hundred Eighty Thousand
Dollars ($480,000),  this Section 12G shall not apply but instead the provisions
of Section 12A shall apply.  Notwithstanding the foregoing,  Landlord may not so
terminate  this Lease  pursuant  to this  Section 12G,  and shall  restore  the
Premises,  if Tenant,  within  fifteen (15) days after  Landlord  exercises such
option to terminate,  agrees in writing as follows:  (i) the amount by which the
funds received by Landlord  (including  insurance  proceeds and any "deductible"
paid in cash by Tenant) are  insufficient to pay the restoration  costs shall be
amortized  over the  remainder  of the  initial  Lease  Term  and all  remaining
extension  periods  pursuant to Section 2.2  (whether  or not  exercised)  with
interest on the unamortized  balance at the then prevailing market rate Landlord
would pay for borrowed funds to  permanently  finance such  restoration  from an
institutional lender following  completion;  (ii) Tenant shall pay as additional
rent such monthly amortization for the remainder of the Lease Term (as it may be
extended);  and (iii) if the Lease Term expires or otherwise  terminates  before
the end of the period over which such costs were amortized, upon such expiration
or  termination  Tenant  shall pay a lump sum payment  equal to the  unamortized
principal balance of such amortized costs.

H. Any  amortization  required to be paid by Tenant  pursuant to this Section 12
shall be paid by Tenant as additional rent in addition to the Base Monthly Rent.

13. CONDEMNATION.

13.1 Definition of Terms.  For the purposes of this Lease, the term (i) "Taking"
means a taking of the Premises or damage to the Premises related to the exercise
of the power of eminent domain and includes a voluntary  conveyance,  in lieu of
court proceedings, to any agency, authority, public utility, person or corporate
entity  empowered to condemn  property;  (ii) "Total Taking" means the taking of
the entire  Premises or so much of the  Premises as to prevent or  substantially
impair the use thereof by Tenant for the uses herein  specified;  (iii) "Partial
Taking"  means the  taking  of only a portion  of the  Premises  which  does not
constitute a Total  Taking;  (iv) "Date of Taking" means the date upon which the
title to the Premises, or a portion thereof, passes to and vests in the

                              - 11 -





condemnor or the effective  date of any order for  possession if issued prior to
the date title vests in the  condemnor;  and (v) "Award" means the amount of any
award made, consideration paid, or damages ordered as a result of a Taking.

13.2 Rights.  The parties agree that in the event of a Taking all rights between
them or in and to an Award shall be as set forth herein and Tenant shall have no
right to any Award except as set forth herein.

13.3 Total Taking. In the event of a Total Taking during the term hereof (i) the
rights of Tenant  under the Lease and the  leasehold  estate of Tenant in and to
the  Premises  shall  cease and be  terminated  as of the Date of  Taking;  (ii)
Landlord  shall  refund to Tenant any prepaid  rent;  (iii)  Tenant shall pay to
Landlord any rent or charges due Landlord  under the Lease,  each prorated as of
the Date of Taking;  (iv) Tenant  shall  receive  from the Award those  specific
portions of the Award  attributable  to trade  fixtures  and moving  expenses of
Tenant and to the  leasehold  improvements  which  Tenant  would be  entitled to
remove from the  Premises;  and (v) the  remainder of the Award shall be paid to
and be the property of Landlord.

13.4 Partial Taking. In the event of a Partial Taking during the term hereof (i)
the rights of Tenant under the Lease and the  leasehold  estate of Tenant in and
to the portion of the Premises taken shall cease and terminate as of the Date of
Taking; (ii) from and after the Date of Taking the Base Monthly Rent shall be an
amount  equal to the  product  obtained by  multiplying  the Base  Monthly  Rent
immediately  prior to the Taking by the quotient obtained by dividing the number
of square  feet  contained  in the  Premises  after the  Taking by the number of
square feet  contained in the Premises  prior to the Taking;  (iii) Tenant shall
receive from the Award the specific portions of the Award  attributable to trade
fixtures of Tenant;  and (iv) the remainder of the Award shall be paid to and be
the property of Landlord.

14. ASSIGNMENT AND SUBLETTING.

The  following  provisions  shall apply to any  assignment,  subletting or other
transfer by Tenant or any  subtenant or assignee or other  successor in interest
of the original Tenant (collectively referred to in this section as "Tenant"):

A. Tenant shall not do any of the following  (collectively referred to herein as
a  "Transfer"),  whether  voluntarily,  involuntarily  or by  operation of Laws,
without  the prior  written  consent of  Landlord,  which  consent  shall not be
unreasonably  withheld or delayed: (i) sublet all or any part of the Premises or
allow it to be  sublet,  occupied  or used by any  person or entity  other  than
Tenant;  (ii)  assign its  interest  in this  Lease;  (iii)  transfer  any right
appurtenant  to this Lease or the Premises;  (iv) mortgage or encumber the Lease
(or  otherwise  use the  Lease  as a  security  device)  in any  manner;  or (v)
terminate  or  materially  amend or  modify  an  assignment,  sublease  or other
transfer that has been previously approved by Landlord. Any Transfer so approved
by Landlord  shall not be effective  until  Tenant has  delivered to Landlord an
executed  counterpart  of the document  evidencing  the Transfer which (i) is in
form  reasonably  approved  by  Landlord,  (ii)  contains  the  same  terms  and
conditions  as stated in Tenant's  notice given to Landlord  pursuant to Section
14B below, and (iii) contains the agreement of the proposed transferee to assume
all  obligations of Tenant  related to the Transfer  arising after the effective
date of such Transfer and to remain jointly and severally  liable  therefor with
Tenant.  If  Landlord  fails to  respond  in writing  to  Tenant's  request  for
Landlord's  consent to a Transfer  within  fifteen  (15) days of receipt of such
request,  Landlord  will be  deemed  to have  consented  to such  Transfer.  Any
attempted  Transfer  without  Landlord's  consent shall  constitute a default by
Tenant and shall be voidable at Landlord's option. Landlord's consent to any one
Transfer  shall not  constitute a waiver of the provisions of this Section 14 as
to any  subsequent  Transfer  nor a  consent  to  any  subsequent  Transfer.  No
Transfer,  even  with the  consent  of  Landlord,  shall  relieve  Tenant of its
personal and primary  obligation to pay the rent and to perform all of the other
obligations  to be  performed by Tenant  hereunder.  The  acceptance  of rent by
Landlord  from any person  shall not be deemed to be a waiver by Landlord of any
provision of this Lease nor to be a consent to any Transfer.

                              - 12 -





B. Tenant shall give Landlord at least thirty (30) days prior written  notice of
any desired  Transfer and of the proposed  terms of such Transfer  including but
not limited to (i) the name and legal  composition  of the proposed  transferee;
(ii) a current financial  statement of the transferee,  financial  statements of
the transferee covering the preceding three years, and (if readily available) an
audited financial  statement of the transferee for a period ending not more than
one year prior to the  proposed  effective  date of the  Transfer,  all of which
statements  are  prepared  in  accordance  with  generally  accepted  accounting
principles; (iii) the nature of the proposed transferee's business to be carried
on in the  Premises;  (iv)  all  consideration  to be given  on  account  of the
Transfer;  (v) a current  financial  statement  of  Tenant;  and (vi) such other
information as may be reasonably  requested by Landlord.  Tenant's  notice shall
not be deemed  to have  been  served  or given  until  such  time as Tenant  has
provided Landlord with all information reasonably requested by Landlord pursuant
to  this  Section 14B.  Tenant  shall   immediately   notify  Landlord  of  any
modification to the proposed terms of such Transfer.

C. If Landlord consents to a Transfer proposed by Tenant,  Tenant may enter into
such Transfer, and if Tenant does so, the following shall apply:

      (i) Tenant shall not be released of its liability for the  performance  of
      all of its obligations under the Lease.

      (ii) If Tenant  assigns its interest in this Lease,  then Tenant shall pay
      to Landlord  fifty percent (50%) of all  consideration  received by Tenant
      over and above (i) the assignee's  agreement to assume the  obligations of
      Tenant under this Lease, and (ii) all Permitted  Transfer Costs related to
      such  assignment.  In the case of assignment,  the amount of consideration
      owed to Landlord  shall be paid to  Landlord  on the same  basis,  whether
      periodic or in lump sum, that such  consideration is paid to Tenant by the
      assignee.

      (iii) If Tenant sublets any part of the Premises, then with respect to the
      space so  subleased,  Tenant shall pay to Landlord  fifty percent (50%) of
      the  positive  difference,   if  any,  between  (i)  all  rent  and  other
      consideration  paid by the  subtenant to Tenant,  less (ii) all  Permitted
      Transfer  Costs  related to such  sublease  and all Base  Monthly Rent and
      additional rent fairly allocable to that part of the Premises  affected by
      such  sublease.  Such amount  shall be paid to Landlord on the same basis,
      whether periodic or in lump sum, that such rent and other consideration is
      paid to Tenant by its Subtenant.  In calculating  Landlord's  share of any
      periodic payments,  all such costs permitted to be deducted from the gross
      consideration received by Tenant shall be first recovered by Tenant.

      (iv)  Tenant's  obligations  under  this  Section 14C shall  survive  any
      assignment or sublease,  and Tenant's  failure to perform its  obligations
      hereunder shall be an event of default by Tenant. At the time Tenant makes
      any payment to Landlord required by this Section 14C, Tenant shall deliver
      an itemized  statement of the method by which the amount to which Landlord
      is  entitled  was  calculated,  certified  by Tenant as true and  correct.
      Landlord shall have the right at reasonable  intervals to inspect Tenant's
      books and records  relating to the  payments due  hereunder.  Upon request
      therefor,  Tenant shall deliver to Landlord copies of all bills,  invoices
      or other  documents upon which its  calculations  are based.  Landlord may
      condition its approval of any Transfer upon obtaining a certification from
      both Tenant and the proposed transferee of all amounts that are to be paid
      to Tenant in connection with such Transfer.

      (v) As used in this Section 14C, the term  "consideration"  shall mean any
      consideration  of any kind  received,  or to be  received,  by Tenant as a
      result of the Transfer,  if such sums are related to Tenant's  interest in
      this Lease or in the Premises, including payments from or on behalf of the
      transferee  (in excess of the fair  market  value  thereof)  for  Tenant's
      assets, fixtures, leasehold improvements,  inventory,  accounts, goodwill,
      equipment, furniture, and general intangibles.

      (vi) As used in this  Section 14C, the term  "Permitted  Transfer  Costs"
      shall mean: (i) all reasonable  leasing  commissions paid to third parties
      not  affiliated  with Tenant in order to obtain the  Transfer in question;
      (ii) all reasonable attorneys' fees incurred by Tenant with respect to the
      Transfer in

                              - 13 -





      question;  and (iii) the cost of all improvements  installed by Tenant for
      such assignee or subtenant pursuant to such assignment or sublease.

D.  Notwithstanding  anything  contained  in this  Section 14, so long as Tenant
otherwise  complies with the  provisions of this section,  Tenant may enter into
any of the following transfers (a "Permitted Transfer") without Landlord's prior
written consent,  and if Tenant does so, it shall have no obligation to make any
payments of consideration  resulting from such Transfer to Landlord  pursuant to
subparagraph 14C:

      (i) Tenant may sublease all or part of the Premises or assign its interest
      in this Lease to any Tenant Affiliate (as defined in subparagraph 14E).

      (ii) Tenant may assign its  interest in the Lease to a  corporation  which
      results  from a merger,  consolidation  or other  reorganization  in which
      Tenant is not the surviving corporation.

      (iii)  Tenant may assign this Lease to a  corporation  which  purchases or
      otherwise acquires all or substantially all of the assets of Tenant.

E.  The  term  "Tenant  Affiliate"  shall  mean  any of the  following:  (i) any
corporation  which owns more than fifty  percent  (50%) of the capital  stock of
Apple Computer,  Inc. which is issued,  outstanding and entitled to vote for the
election of directors (an "Apple  Parent");  (ii) any corporation in which Apple
Computer,  Inc.  owns more than fifty percent (50%) of the capital stock that is
issued,  outstanding  and  entitled to vote for the  election of  directors  (an
"Apple Sub");  and (iii) any  corporation  or other entity in which either Apple
Computer,  Inc., an Apple  Parent,  or an Apple Sub owns more than fifty percent
(50%) of the beneficial interest (or, in the case of a corporation,  the capital
stock issued. outstanding, and entitled to vote for the election of directors).

F. Tenant  shall  reimburse  Landlord  for all  reasonable  attorney's  fees and
processing  costs incurred by Landlord in connection with any proposed  Transfer
submitted to Landlord for its approval.

15. SUBORDINATION.

15.1  Subordination.  This  Lease at  Landlord's  option  shall be  subject  and
subordinate  to all ground or  underlying  leases which now exist  affecting the
Premises  and to the lien of any  mortgages  or deeds of trust in any  amount or
amounts  whatsoever  which now exist  against  the  Premises,  or on or  against
Landlord's  interest or estate therein or on or against any ground or underlying
lease,  without  the  necessity  of the  execution  and  delivery of any further
instruments  on the part of  Tenant to  confirm  such  subordination;  provided,
however,  that Landlord shall use all reasonable  efforts to obtain within sixty
(60) days  from the date  hereof a  recognition  and  non-disturbance  agreement
whereby the lessor under any such ground or  underlying  lease and holder of any
mortgage or deed of trust shall agree that,  so long as Tenant is not in default
hereunder,  this Lease shall remain in full force and effect notwithstanding the
termination  of any such lease or foreclosure of such mortgage or deed of trust.
If any mortgagee,  trustee or ground lessor shall elect to have this Lease prior
to the lien of its  mortgage,  deed of trust or ground  lease,  and  shall  give
written  notice  thereof to Tenant,  this  Lease  shall be deemed  prior to such
mortgage,  deed of trust or ground  lease,  whether this Lease is dated prior or
subsequent  to the date of said  mortgage,  deed of trust or ground lease or the
date of the recording thereof.

15.2 Subordination  Agreements.  Tenant covenants and agrees to promptly execute
and deliver upon demand without charge  therefor,  any instrument or instruments
of  subordination  necessary to  subordinate  this Lease to any future ground or
underlying  leases and/or to the lien of any future mortgage or deed of trust in
any amount or amounts whatsoever which may hereafter be placed by Landlord on or
against the Premises,  or on or against Landlord's interest or estate therein or
on or against any ground or underlying lease;  provided,  however,  Tenant shall
not be required to execute and deliver any such  subordination  agreement unless
the lender/lessor consents in writing to the Lease and agrees in writing that in
the event of  termination of the lease,  foreclosure of the mortgage,  or in the
event the lender comes into possession or acquires

                              - 14 -





title to the  Premises  as a result of the  foreclosure  of its  mortgage or the
notes  secured  thereby,  or as a result of any other means,  the  lender/lessor
agrees  that the Lease  shall not be  terminated  and that  lender/lessor  shall
recognize  Tenant and further  agrees that Tenant  shall not be disturbed in its
possession of the Premises for any reason other than one which would entitle the
Landlord to terminate the Lease under its terms or that would cause, without any
further  action by  Landlord,  the  termination  of the  Lease or would  entitle
Landlord to dispossess the Tenant from the Premises.

15.3 Quiet Enjoyment. Landlord covenants and agrees with Tenant that upon Tenant
paying  rent and other  monetary  sums due under  the Lease and  performing  its
covenants and conditions,  Tenant shall and may peaceably and quietly have, hold
and enjoy the Premises for the Term,  subject  however to the terms of the Lease
and of any of the ground leases, mortgages or deeds of trust described above.

15.4 Attornment.  In the event any proceedings are brought for default under any
ground or underlying lease or in the event of foreclosure or the exercise of the
power of sale under any mortgage or deed of trust made by Landlord  covering the
Premises, Tenant shall attorn to the purchaser upon any such foreclosure or sale
and recognize  such  purchaser as the Landlord  under this Lease;  provided said
purchaser expressly agrees in writing to be bound by the terms of the Lease.

15.5  Modifications  to Lease Required by Lender:  In the event an institutional
lender reasonably  requires that modifications be made to this Lease in order to
protect its  security  interest in the Lease and as a condition to making a loan
to Landlord  secured by the  Premises,  Tenant agrees to execute and deliver any
reasonable  modifications  of this Lease so required by such lender (i) which do
not materially and adversely  affect Tenant's  rights or materially  increase or
expand Tenant's  obligations  under this Lease, and (ii) which do not in any way
change the Lease Term,  the options to extend the Lease Term,  the Base  Monthly
Rent,  Tenant's  right to assign  and  sublease  the  Premises,  or  Section 18
regarding Hazardous Materials.

16. DEFAULT: REMEDIES.

16.1 Default. The occurrence of any of the following shall constitute a material
default and breach of this Lease by Tenant:

A. Any failure by Tenant to pay the rent or any other  monetary sums required to
be paid hereunder, where such failure continues for seven (7) days after written
notice thereof by Landlord to Tenant;

B. The abandonment of the Premises by Tenant;

C. A failure by Tenant to observe and perform any other provisions of this Lease
to be observed or performed by Tenant,  where such failure  continues for twenty
(20) days after written notice thereof by Landlord to Tenant; provided, however,
that if the nature of such  default is such that the same cannot  reasonably  be
cured  within such twenty (20) day period,  Tenant  shall not be deemed to be in
default if Tenant shall  within such period  commence  such cure and  thereafter
diligently prosecute the same to completion;

D. The making by Tenant of any general assignment for the benefit
of creditors;

E. A court makes or enters any decree or order with  respect to Tenant or Tenant
submits  to or seeks a decree  or order (or  petition  or  pleading  is filed in
connection  therewith)  which (i) grants or constitutes  (or seeks) an order for
relief,  appointment of a trustee or confirmation of a reorganization plan under
the Bankruptcy  Laws of the United  States;  (ii) approves as properly filed (or
seeks such approval of) a petition seeking  liquidation or reorganization  under
said  Bankruptcy  Laws or any other debtor's relief law or statute of the United
States or any state thereof;  (iii) otherwise  directs (or seeks) the winding up
or liquidation of Tenant; provided,  however, that if any such petition,  decree
or order is not voluntarily filed or made by Tenant, that

                              - 15 -





Tenant  shall not be in default  until such  petition,  decree or order  remains
undischarged for a period of sixty (60) days. 16.2 Remedies. In the event of any
such material default or breach by Tenant,  Landlord may at any time thereafter,
with or without notice and demand and without limiting  Landlord in the exercise
of any right or remedy at law or in equity which  Landlord may have by reason of
such default or breach:

A.  Maintain  this Lease in full force and effect and recover the rent and other
monetary  charges as they  become due,  without  terminating  Tenant's  right to
possession, irrespective of whether Tenant shall have abandoned the Premises. In
the event  Landlord  elects to not terminate the Lease,  Landlord shall have the
right to attempt to re-let the  Premises  at such rent and upon such  conditions
and for such a term,  and to do all acts  necessary  to maintain or preserve the
Premises as Landlord deems reasonable and necessary without being deemed to have
elected to  terminate  the Lease  including  removal of all persons and property
from the  Premises;  such  property  may be  removed  and  restored  in a public
warehouse  or  elsewhere  at the cost of and for the  account of Tenant.  In the
event any such re-letting occurs, this Lease shall terminate  automatically upon
the new Tenant taking possession of the Premises, and Landlord shall be entitled
to recover damages for Tenant's breach pursuant to Section 16.2B.

B.  Terminate  Tenant's  right to possession by any lawful means,  in which case
this Lease shall terminate and Tenant shall immediately  surrender possession of
the Premises to  Landlord.  In the event the Lease is so  terminated  because of
Tenant's default,  Landlord shall be entitled to recover from Tenant all damages
incurred by Landlord by reason of Tenant's default including without  limitation
thereto,  the  following:  (i) the worth at the time of award of any unpaid rent
which had been  earned at the time of such  termination;  plus (ii) the worth at
the time of award of the amount by which the unpaid  rent which  would have been
earned  after  termination  until the time of award,  exceeds the amount of such
rental loss that Tenant proves could have been  reasonably  avoided;  plus (iii)
the worth at the time of award of the  amount by which the  unpaid  rent for the
balance of the term after the time of award  exceeds  the amount of such  rental
loss that Tenant proves could be reasonably avoided;  plus (iv) any other amount
necessary to  compensate  Landlord for all the detriment  proximately  caused by
Tenant's  failure to perform  its  obligations  under this Lease or which in the
ordinary  course of things  would be  likely  to result  therefrom;  plus (v) at
Landlord's  election,  such  other  amounts  in  addition  to or in  lieu of the
foregoing as may be permitted from time to time by applicable state law. As used
in clauses (i) and (ii)  above,  the "worth at the time of award" is computed by
allowing  interest at the rate of ten  percent  (10%) per annum from the date of
default.  As used in clause  (iii),  the "worth at time of award" is computed by
discounting such amount at the discount rate of the U.S. Federal Reserve Bank at
the time of award  plus  one  percent  (1%).  The term  "rent",  as used in this
Section 16,  shall be deemed to be and to mean the rent to be paid  pursuant to
Section 3 and all other monetary sums required to be paid by Tenant  pursuant to
the terms of this Lease.

16.3 Default by Landlord. Landlord shall not be in default unless Landlord fails
to perform obligations  required of Landlord within a reasonable time, but in no
event later than thirty (30) days after written notice by Tenant to Landlord and
to the holder of any first mortgage or deed of trust covering the Premises whose
name and address  shall have  theretofore  been  furnished to Tenant in writing,
specifying  wherein  Landlord  has failed to perform such  obligation;  provided
however,  that if the  nature of  Landlord's  obligation  is such that more than
thirty (30) days are required for  performance,  then  Landlord  shall not be in
default if Landlord  commences  performance  within such  thirty-day  period and
thereafter diligently prosecutes the same to completion.

16.4 Tenant's  Remedies.  In addition to all other rights and remedies of Tenant
under the terms of this Lease or applicable  Laws and subject to the  provisions
of Section 16.3,  Tenant  shall have the right to cure any  default of Landlord
under the Lease, and to demand  reimbursement  from Landlord of the cost of such
cure, with interest thereon at the rate of ten percent (10%) per annum, from the
date of the expenditure until repaid.

                              - 16 -





17. BROKERAGE COMMISSIONS.  Landlord and Tenant represent that they have not had
any  dealings  with  any  real  estate  brokers  or  salesmen  or  incurred  any
obligations  for the payment of real estate  brokerage  commissions  or finder's
fees which would be earned or due and payable by reason of the execution of this
Tenant.

18. HAZARDOUS MATERIALS. Landlord and Tenant agree as follows
with respect to the existence or use of "Hazardous Material" (as
defined below) on the Premises:

A. As used herein, the following terms shall have the following meaning:

      (1)  The  term  "Hazardous   Materials"  shall  mean  (i)  polychlorinated
      biphenyls; (ii) radioactive materials; and (iii) any chemical, material or
      substance now or hereafter  defined as or included in the  definitions  of
      "hazardous   substances",   "hazardous   waste",   "hazardous   material",
      "extremely  hazardous  waste",  "restricted  hazardous  waste"  or  "toxic
      substances"  or  words  of  similar  import  under  any  applicable   laws
      including,  without  limitation,  any material or  substance  which is (i)
      defined  as  a  "hazardous   waste",   "extremely   hazardous  waste",  or
      "restricted  hazardous waste" under Sections 25115,  25117 or 15122.7,  or
      listed pursuant to Section 25140 of the California Health and Safety Code?
      Division 20,  Chapter 6.5 (Hazardous  Waste Control Law),  (ii) defined as
      "hazardous  substance"  under Section 25316 of the  California  Health and
      Safety Code, Division 20, Chapter 6.8 (Carpenter-Presley-Tanner  Hazardous
      Substances  Account  Act),  (iii)  defined  as  a  "hazardous   material",
      "hazardous  substance",  or  "hazardous  waste" under Section 25501 of the
      California  Health and Safety Code,  Division 20, Chapter 6.95  (Hazardous
      Materials  Release,  Response,  Plans and  Inventory),  (iv)  defined as a
      "hazardous  substance"  under Section 25281 of the  California  Health and
      Safety Code,  Division 20, Chapter 6.7  (Underground  Storage of Hazardous
      Substances), (v) petroleum, (vi) asbestos, (vii) listed under Article 9 or
      defined as "hazardous" or "extremely  hazardous  pursuant to Article II of
      Title 22 of the California  Administrative  Code,  Division 4, Chapter 20,
      (viii)  designated as a "hazardous  substance"  pursuant to Section 311 of
      the Federal Water Pollution  Control Act, 33 U.S.C. 1251 et seq. or listed
      pursuant  to Section 307 of the Federal  Water  Pollution  Control Act (33
      U.S.C. 1317), (ix) defined as a "hazardous waste" pursuant to Section 1004
      of the Federal Resource  Conservation and Recovery Act, 42 U.S.C.  6901 et
      seq.,  (x) defined as a "hazardous  substance"  pursuant to Section 101 of
      the Comprehensive  Environmental  Response,  Compensations,  and Liability
      Act, 42 U.S.C.  9601 et seq., or (xi) regulated under the Toxic Substances
      Control Act, 15 U.S.C. 2601 et seq.

      (2) The term "Hazardous  Materials  Laws" shall mean any local,  state and
      federal  laws,  rules,  regulations,  or  ordinances  relating to the use,
      generation,  manufacture,  installation,  release,  discharge,  storage or
      disposal of hazardous materials.

      (3) The term  "Landlord's  Agents"  as used in this  Section 18 shall mean
      Landlord's    agents,     representatives,     employees,     contractors,
      subcontractors, directors, officers, partners and invitees.

      (4) The term  "Tenant's  Agents"  as used in this  Section 18 shall  mean
      Tenant's agents, representatives,  employees, contractors, subcontractors,
      directors, officers, partners and invitees.

B.  Tenant's  Right to  Investigate:  Tenant  shall be  entitled  to cause  such
inspections,  soils and groundwater  tests, and other  evaluations to be made of
the Premises as Tenant  deems  necessary  regarding  (i) the presence and use of
Hazardous  Materials  in or about  the  Premises,  and (ii)  the  potential  for
exposure of Tenant's employees and other persons to any Hazardous Materials used
and  stored by  previous  occupants  in or about  the  Premises.  To  facilitate
assigning  responsibility  for the  presence of any  Hazardous  Materials on the
Premises,  Tenant  shall use its best  efforts  to take all  samples of soil and
groundwater  necessary in the course of its inspection and evaluation before the
Commencement  Date, and shall thereafter cause the evaluation of such samples to
be conducted as promptly as reasonably  possible.  Tenant shall provide Landlord
with copies of all inspections,  tests and evaluations.  Tenant shall indemnify,
defend and hold

                              - 17 -





Landlord  harmless  from any cost,  claim or expense  arising from such entry by
Tenant or from the  performance  of any such  investigation  by such Tenant.  C.
Landlord's Representations:  Landlord hereby represents and warrants to the best
of Landlord's  knowledge that the Premises are, as of the date of this Lease, in
compliance  with all Hazardous  Materials Laws.  Notwithstanding  the foregoing,
Landlord makes no  representation  or warranty  concerning  the compliance  with
Hazardous  Materials Laws of Apple  Computer,  Inc.,  Four Phase Systems,  Inc.,
Motorola Computer Systems,  Inc., or Motorola Cupertino Operations,  Inc. during
the period each such entity was in possession of the Premises. Nothing contained
in this Section 18 is intended to modify any obligation  Apple  Computer,  Inc.,
Four Phase Systems, Inc., Motorola Computer Systems, Inc., or Motorola Cupertino
Operations,  Inc. may have with respect to Hazardous  Materials under either the
lease  dated  March  27,  1980  or  that  sublease  of  the  Premises,  entitled
"Commercial Office Sublease",  dated May 1984,  executed by Four-Phase  Systems,
Inc., a Delaware corporation as sublessor and Apple Computer, Inc. as sublessee.

D. Tenant's Obligation to Indemnify: Tenant, at its sole cost and expense, shall
indemnify,  defend,  protect and hold  Landlord and  Landlord's  Agents from and
against  any  and  all  costs  or  expenses,  including  those  described  under
subparagraphs (a), (b) and (c) herein below set forth, arising from or caused in
whole or in part, directly or indirectly, by:

      (1) Tenant's or Tenant's Agents' use, analysis,  storage,  transportation,
      disposal,   release,   threatened  release,  discharge  or  generation  of
      Hazardous Materials to, in, on, under, about or from the Premises; or

      (2)  Tenant's  or  Tenant's  Agents'  failure  to  comply  with  Hazardous
      Materials Laws; or

      (3) Any release of Hazardous  Materials on or onto the Premises  caused by
      any party other than Landlord or Landlord's  Agents  occurring  during the
      Lease Term but  specifically  excluding  (i)  below-surface  migration  of
      Hazardous Material in the groundwater underlying the Premises from sources
      outside the Premises,  and (ii) contamination by Hazardous  Materials that
      were present on or under the Premises  prior to the time that Tenant first
      entered into possession of the Premises.

The cost and expenses indemnified against include the following:

(a)  Any  and  all  claims,  actions,  suits,   proceedings,   losses,  damages,
liabilities,  deficiencies,  forfeitures,  penalties,  fines,  punitive damages,
costs or expenses;

(b) Any  claim,  action,  suit or  proceeding  for  personal  injury  (including
sickness,   disease,   or  death),   tangible  or  intangible  property  damage,
compensation for lost wages,  business  income,  profits or other economic loss,
damage  to the  natural  resources  of  the  environment,  nuisance,  pollution,
contamination,   leaks,  spills,  releases  or  other  adverse  effects  on  the
environment;

(c) The  cost of any  repair,  clean-up,  treatment,  or  detoxification  of the
Premises  necessary to bring the Premises  into  compliance  with all  Hazardous
Materials Laws,  including the preparation  and  implementation  of any closure,
disposal,  remedial  action,  or other actions with regard to the Premises,  and
expenses  (including,   without  limitation,   reasonable  attorneys'  fees  and
consultants' fees, investigation and laboratory fees, court costs and litigation
expenses).

E. Tenant's  Obligation to Remediate  Contamination:  Tenant shall,  at its sole
cost and  expense,  promptly  take any and all  action  necessary  to  remediate
contamination  of the Premises by Hazardous  Materials to the extent required by
any Hazardous  Materials Law or any  governmental  agency if such  contamination
results from or is caused by any of the actions,  causes, or events described in
Section 18D(1), (2), or (3).

                              - 18 -





F.  Obligation to Notify:  Landlord and Tenant shall each give written notice to
the other as soon as reasonably  practicable of (i) any  communication  received
from any governmental  authority  concerning Hazardous Material which relates to
the Premises and (ii) any  contamination of the Premises by Hazardous  Materials
which constitutes a violation of any Hazardous Material Law.

G. Survival: The obligations of Landlord and Tenant under this
Section 18 shall survive the expiration or earlier termination of
this Lease.

H.  Interpretation:  The rights and  obligations  of  Landlord  and Tenant  with
respect to issues relating to Hazardous Materials are exclusively established by
this Section 18; provided, however, that nothing in this Section 18H is intended
to limit  Landlord's  remedies in the event of a default  under this Section 18.
Any default  under this Section 18 shall  constitute  a default  under the Lease
(subject to any  requirements for notice and an opportunity to cure as set forth
in Section 16.1).  In the event of any  inconsistency  between any other part of
this Lease and this Section 18, the terms of this Section 18 shall control.

I. Certification and Closure: On or before the expiration or earlier termination
of the term of the  Lease,  Tenant  shall  deliver to  Landlord a  certification
executed by Tenant stating that, to the best of Tenant's knowledge, there exists
no  violation of  Hazardous  Materials  Laws  resulting  from the use,  storage,
release or disposal of  Hazardous  Materials on or about the Premises by Tenant,
its agents, employees,  invitees or contractors. If pursuant to local ordinance,
state or federal law,  Tenant is required,  at the expiration of the Lease Term,
to submit a closure plan for the Premises to a local,  state or federal  agency,
then Tenant shall furnish to Landlord a copy of such plan.

19. MISCELLANEOUS.

19.1 Estoppel Certificate.

A. Tenant shall at any time upon not less than fifteen (15) business days' prior
written  notice from  Landlord  execute,  acknowledge  and deliver to Landlord a
statement in writing (i)  certifying  that this Lease is unmodified  and in full
force and effect (or, if modified,  stating the nature of such  modification and
certifying that this Lease, as so modified, is in full force and effect) and the
date to which the rent and  other  charges  are paid in  advance,  if any,  (ii)
acknowledging that there are not, to Tenant's knowledge, any uncured defaults on
the part of Landlord hereunder,  or specifying such defaults if any are claimed,
and (iii) certifying,  to the best of Tenant's knowledge, such other information
and facts  concerning  this  Lease as may be  reasonably  requested  by a lender
making a loan to Landlord to be secured by a deed of trust or mortgage  covering
the Premises or a purchaser of the Premises from  Landlord.  Any such  statement
may be conclusively relied upon by any prospective  purchaser or encumbrances of
the Premises.

B.  Tenant's  failure  to  deliver  such  statement  within  such time  shall be
conclusive  upon Tenant (i) that this Lease is in full force and effect  without
modification  except as may be represented  by Landlord,  (ii) that there are no
uncured  defaults in  Landlord's  performance,  and (iii) that not more than one
month's rent has been paid in advance.

19.2  Transfer of Landlord's  Interest.  In the event of a sale or conveyance by
Landlord  of  Landlord's  interest  in the  Premises  other than a transfer  for
security  purposes  only,  Landlord  shall be  relieved  from and after the date
specified in such notice of transfer of all obligations and liabilities accruing
thereafter on the part of the Landlord,  provided that any funds in the hands of
Landlord  at the time of  transfer  in which  Tenant has an  interest,  shall be
delivered to the successor of Landlord.  This Lease shall not be affected by any
such sale and Tenant agrees to attorn to the purchaser or assignee  provided all
of  Landlord's  obligations  hereunder  accruing  after the date of transfer are
assumed in writing by the transferee.

                              - 19 -





19.3 Captions; Attachments: Defined Terms.
A. The captions of the paragraphs of this Lease are for
convenience only and shall not be deemed to be relevant in
resolving any question of interpretation or construction of any
section of this Lease.

B.  Exhibits  attached  here to, and  addenda  and  schedules  initialed  by the
parties,  are  deemed by  attachment  to  constitute  part of this Lease and are
incorporated herein.

C. The words  "Landlord" and "Tenant" as used herein shall include the plural as
well as the  singular.  Words used in neuter  gender  include the  masculine and
feminine and words in the  masculine and feminine  gender  include the neuter If
there be more than one Landlord or Tenant,  the  obligations  hereunder  imposed
upon  Landlord or Tenant shall be joint and several.  If the Tenants are husband
and wife, the obligations  shall extend  individually to their sole and separate
property as well as to their community property.

19.4 Entire  Agreement.  This instrument along with any exhibits and attachments
hereto  constitutes the entire agreement between Landlord and Tenant relative to
the Premises and this Agreement and the exhibits and attachments may be altered,
amended or revoked only by an instrument in writing  signed by both Landlord and
Tenant.  Landlord and Tenant agree hereby that all prior or contemporaneous oral
agreements  between and among  themselves  and their  agents or  representatives
relative  to the  leasing  of the  Premises  are  merged in or  revoked  by this
Agreement.

19.5 Severability.  If any term or provision of this Lease shall, to any extent,
be  determined  by  a  court  of  competent   jurisdiction   to  be  invalid  or
unenforceable,  the remainder of this Lease shall not be affected  thereby,  and
each term and  provision  of the Lease  shall be valid  and  enforceable  to the
fullest extent permitted by law.

19.6 Costs of Suit.

A. If Tenant or  Landlord  shall  bring any action for any  relief  against  the
other,  declaratory or otherwise,  arising out of this Lease, including any suit
by Landlord for the recovery of rent or possession  of the Premises,  the losing
party shall pay the successful  party a reasonable sum for attorneys' fees which
shall be deemed to have accrued on the  commencement of such action and shall be
paid whether or not such action is prosecuted to judgment.

B. In the event Landlord is made a party to any litigation  arising from the use
of the Premises by Tenant,  its agents,  employees,  contractors  or invitees or
arising from any breach or default on the part of Tenant in the  performance  of
any  covenant  or  agreement  on the part of Tenant to be  performed  under this
Lease,  Tenant covenants to save and hold Landlord harmless from any judgment in
such litigation  rendered  against Landlord or the Premises or any part thereof,
and all  costs  and  expenses  incurred  by  Landlord  in  connection  with such
litigation,  including  reasonable  attorneys'  fees  paid  by  Landlord  to its
attorneys;  provided, however, that such hold harmless agreement by Tenant shall
not apply to the following:  (i) liability  incurred by Landlord  resulting from
its gross negligence or willful misconduct; (ii) any litigation, judgment, claim
or  liability  related to  Hazardous  Materials,  it being the  agreement of the
parties that the subject of Hazardous  Materials is governed  exclusively by the
provisions of Section 18 of this Lease.

19.7 Time: Joint and Several Liability. Time is of the essence of this Lease and
each and  every  provision  hereof.  All the  terms,  covenants  and  conditions
contained in this Lease to be  performed  by either party shall  consist of more
than one person or  organization,  shall be deemed to be joint and several,  and
all rights and remedies of the parties shall be cumulative and  non-exclusive of
any other remedy at law or in equity.

19.8 Binding Effect: Choice of Law. Subject to any provision
hereof restricting assignment or subletting by Tenant and subject
to Section 19.2, all of the provisions hereof shall bind and
inure to the benefit of the parties

                              - 20 -





hereto  and  their  respective  heirs,  legal  representatives,  successors  and
assigns. This Lease shall be governed by the laws of the State of California.

19.9 Waiver.  No covenant,  term or  condition or the breach  thereof,  shall be
deemed waived, except by written consent of the party against whom the waiver is
claimed,  and any waiver or the breach of any covenant,  term or condition shall
not be deemed to be a waiver of any preceding or  succeeding  breach of the same
or any other covenant, term or condition.

19.10  Surrender of Premises.  The voluntary or other surrender of this Lease by
Tenant, or a mutual cancellation  thereof shall not work a merger, and shall, at
the  option  of  the  Landlord,  terminate  all  or any  existing  subleases  or
subtenancies,  or may, at the option of Landlord  operate as an assignment to it
or any or all such subleases or subtenancies.

19.11 Holding Over.  This Lease shall  terminate  without  further notice at the
expiration of the Lease Term. Any holding over by Tenant after  expiration shall
not  constitute  a renewal or  extension  or give Tenant any rights in or to the
Premises except as expressly provided in this Lease; provided,  however, that in
the event Tenant  notifies  Landlord in writing at least ninety (90) days before
the  expiration of the Lease Term Tenant shall be entitled to a one-time  thirty
(30) day extension of the  expiration of the Lease Term.  Any holding over after
the  expiration  with the consent of Landlord shall be construed to be a tenancy
from month to month,  at one hundred  twenty-five  percent (125%) of the monthly
rent for the last month of the Lease Term,  and shall  otherwise be on the terms
and conditions herein specified insofar as applicable.

19.12 Reasonable Consent. Except as limited elsewhere in this Lease, wherever in
this Lease  Landlord or Tenant is  required  to give  consent or approval to any
action  on the  part  of the  other,  such  consent  or  approval  shall  not be
unreasonably withheld or delayed.

19.13  Recording.  Either  party  shall,  upon  request of the  other,  execute,
acknowledge and deliver to the other a "short form" memorandum of this Lease for
recording purposes.  Thereafter,  either party may record such memorandum in the
Official Records of Santa Clara County, California.

19.14  Notices.  All  notices or demands of any kind  required  or desired to be
given by  Landlord  or Tenant  hereunder  shall be in writing and shall be given
only by registered, certified, or "Express" mail, or by Federal Express or other
similar courier  service,  return receipt  requested,  postage  prepaid,  to the
recipient  at its  addresses  as follows,  which shall be deemed given or served
when actually received:

Landlord: c/o Berg & Berg Developers
10050 Bandley Drive
Cupertino, CA 95014

Tenant: Apple Computer, Inc.
10500 North De Anza Boulevard
Cupertino, CA 95014

With copies to: Apple Computer, Inc.
20525 Mariani Avenue
Cupertino, CA 95014
Attn: Real Estate Department

Apple Computer, Inc.
20525 Mariani Avenue
Cupertino, CA 95014
Attn: General Counsel

Either party may change its address for notice by giving  written  notice to the
other party in accordance with the provisions of this paragraph.

19.15  Authority.  Landlord and Tenant hereby represent and warrant to the other
party that each  individual  executing  this  Lease on behalf of the  warranting
party is duly authorized to execute and deliver this Lease on behalf

                              - 21 -





of the  warranting  party  and that this  Lease is  binding  upon said  party in
accordance with its terms.

19.16  Appointment of Landlord's  Agent.  The Landlord  originally  named herein
hereby appoints Berg & Berg Developers, a California partnership,  as Landlord's
attorney-in-fact  for the  purpose  of,  and with  full  power  to, on behalf of
Landlord,  grant any consents or approvals contemplated by this Lease or request
by Tenant and enter into any  modification  or amendment of this Lease,  and any
act by such agent on behalf of Landlord  shall be binding upon  Landlord so long
as such act is in writing  executed by such agent.  The  authority so granted by
Landlord  may  be  revoked  by  Landlord  by an  instrument  in  writing,  which
revocation  shall  only be  effective  from  and  after  the date a copy of such
written revocation is delivered to Tenant.

19.17 Condition to Effectiveness  of Lease.  The  effectiveness of this Lease is
conditioned  upon the termination of the following  leases effective as of April
1, 1989:  (i) that lease for the Premises dated March 27, 1980 by and between De
Anza Boulevard  Investments,  a limited  partnership,  as lessor, and Four-Phase
Systems,  a Delaware  corporation,  as  lessee;  and (ii) that  sublease  by and
between Four-Phase  Systems,  Inc., as sublessor,  and Apple Computer,  Inc., as
sublessee.  In the event such leases are not so terminated effective as of April
1, 1989, then this Lease shall terminate and be of no further force or effect.

IN WITNESS  WHEREOF,  Landlord and Tenant have  executed this Lease the date and
year first above written.

TENANT:

 APPLE COMPUTER, INC.,
 a California corporation

By: /s/ Albert A. Eisenstat
Albert A. Eisenstat
Senior Vice President

Dated: 3/30/89

LANDLORD:

DE ANZA BOULEVARD INVESTMENTS,
a limited partnership

By: /s/ Carl E. Berg
Carl E. Berg, Trustee of the Carl E. Berg Revocable Trust

BERG & BERG DEVELOPERS,
a California partnership

By: /s/ Carl E. Berg
Carl E. Berg, General Partner

                              - 22 -





                                    EXHIBIT A

[CLTA Preliminary Title Report]





                               EXTENSION OF LEASE

This Extension of Lease is made on April , 1991, between Carl E. Berg & Mary Ann
Berg  Trustees  of the Berg  Living  Trust,  UTA  dated  May 1,  1981,  as to an
undivided 81.01% interest,  Clyde Berg & Nancy Berg,  Trustees of the Clyde Berg
Living Trust UTA dated  December 17, 1981,  as to an undivided  11.83% and Clyde
berg,  Trustee  of Carl Berg  Child's  Trust UTA dated  June 2,  1978,  as to an
undivided  7.16%  interest,  ("Lessor"),  whose address is 10050 Bandley  Drive,
Cupertino, California 95014, and Apple Computer, Inc., ("Lessee"), whose address
is 20525 Mariani, Cupertino, California 95014, Attn: Real Estate Department, who
agree as follows:

1.  Recitals  This  Extension of Lease is made with  reference to the  following
facts and objectives:

      a) The Premises are commonly known as 10300 Bubb Road Cupertino.

      b) The  parties  desire to extend the term of the Lease for an  additional
      period of two (2) years and to amend the Lease.

2. Extension of Term. The term of Lease is extended for an Additional  period of
two (2) years from and after  November 30, 1991 through and  including  November
30, 1993. (referenced as paragraph 32a and 32b)

3. Minimum Monthly Rent.  Commencing  December 1, 1991, the monthly rent for the
extended term shall be increased  $21,762.00 per month,  payable pursuant to the
Lease. The monthly rent will increase on December 1, 1992 to $22,230.00

4.  Effectiveness of Lease.  Except as set forth in this Extension and Amendment
of Lease,  all the  provisions  of the Lease shall remain  unchanged and in full
force and effect.

Lessor:

Carl E. Berg & Mary Ann Berg Trustees of the Berg Living Trust, UTA dated May 1,
1981, as to an undivided 81.01% interest,  Clyde Berg & Nancy Berg,  Trustees of
the Clyde Berg Living Trust UTA dated Dec. 17, 1981, as to an undivided  11.83%,
and Clyde Berg, Trustee of Carl Berg Child's Trust UTA dated June 2, 1989, as to
an undivided 7.16% interest

By: /s/ Carl E. Berg
Its: G. P.
Date: 5/15/91

Lessee:
Apple Computer, Inc.
By: /s/ Joseph A Graziano
Joseph A Graziano
Its: Executive Vice President & Chief Financial Officer
Date: May, 30 1491





April 17, 1992
Via Federal Express

       NOTICE OF EXERCISE OF OPTION TO EXTEND TERM OF LEASE

Carl E. Berg and Mary Ann Berg
Clyde Berg and Nancy Berg
10050 Bandley Drive
Cupertino, California 95014

Re: Lease for the Premises commonly known as 20605, 20665, and
20705 Valley Green Drive, Cupertino, California

Ladies and Gentlemen:

McDonnell Douglas Corporation, a Maryland corporation, as successor to Tymshare,
Inc. and as the current  lessee under that certain  Lease dated  January 6, 1978
executed by and between  John A. Sobrato and Susan R. Sobrato as to an undivided
45% interest, and Carl E. Berg and Mary Ann Berg as to an undivided 45% interest
and Ann S. Russo as to a 10% interest (collectively "Lessor") and Tymshare, Inc.
a California corporation  ("Lessee"),  as amended, for the property described in
the Lease,  as amended,  commonly  known as 20605,  20665 and 20705 Valley Green
Drive, Cupertino,  California, hereby gives notice pursuant to Paragraph 2(b) of
the Lease that it  exercises  its option to extend the term of the Lease for one
additional five (5) year term commencing automatically as of the expiration date
of the initial  lease term.  Pursuant to this notice of exercise of option,  the
extended term of the Lease will expire on December 31, 1997.

MCDONNELL DOUGLAS CORPORATION, a Maryland Corporation

 /s/ Gerald J. Olsen.
By: Gerald J. Olsen
Director of Corporate Properties/Facilities

cc:
(via Federal Express)          (via Federal Express)
Apple Computer, Inc.           Apple Computer Inc.
10201 DeAnza Boulevard    20525 Mariani Avenue
Cupertino, CA 95014 .     Cupertino, CA 95014
Attn: General Counsel          Attn: R.E. Department, MS 16-0





                               LEASE EXTENSION #2
This  Extension  of  Lease  is made on  December  , 1992,  between  Berg  Family
Partnership,  a California  General  Partnership,  ("Lessor"),  whose address is
10050 Bandley Drive,  Cupertino,  California  95014,  and Apple Computer,  Inc.,
("Lessee"),  whose address is 20525 Mariani, Cupertino,  California 95014, Attn:
Real Estate Department, who agree as follows:

1.  Recitals  This  Extension of Lease is made with  reference to the  following
facts and objectives:

      a) The Premises are commonly known as 10300 Bubb Road, Cupertino.

      b) The  Parties  desire to extend the term of the Lease for an  additional
      period of three (3) years and to amend the Lease.

2.  Extension of Term The term of Lease is extended for an additional  period of
three (3) years from and after November 30, 1993 through and including  November
30, 1996.

3. Minimum  Monthly Rent  Commencing  December 1, 1993, the monthly rent for the
extended term shall be increased to $23,400 per month,  payable  pursuant to the
provision of the Lease.

4.  Lessor  agrees to  replace  existing  package  HVAC  units with 2-27 ton VAV
systems and to put roof in top  condition.  Lessee shall have no obligation  for
any roof repair unless caused by their penetration of roof. If Lessee penetrates
the roof, Lessee agrees to use Dale's  Waterproofing for repairs in order not to
void Lessor's roof warranty.

5. Effectiveness of Lease Except as set forth in this Extension and Amendment of
Lease,  all the provisions of the Lease shall remain unchanged and in full force
and effect.

Lessor:

Berg Family Partnership

By: /s/ Carl E. Berg
Its: G. P.
Date: 12/21/92

Lessee:
Apple Computer, Inc.

By: Glenn N. Barber
Glenn N. BarberIts: Vice President, Real Estate, Construction and
Facilities
Date: 1/14/93

By: /s/ Joseph A. Graziano
Joseph A. Graziano
Its: Executive Vice President and Chief Financial Officer
Date: 1/14//93





RECORDING REQUESTED BY:

Richard T. Tarrant, Esq.
BARTKO, TARRANT & MILLER
900 Front Street, Suite 300
San Francisco, CA 94111

WHEN RECORDED, RETURN TO:

Richard T. Tarrant, Esq.
BARTKO, TARRANT & MILLER
900 Front Street, Suite 300
San Francisco, CA 94111

          MEMORANDUM OF ASSIGNMENT OF LEASE AND SUBLEASE

This Memorandum of Assignment of Lease and Sublease  (hereinafter  "Memorandum")
is  entered  into by and  between  MCDONNELL  DOUGLAS  CORPORATION,  a  Maryland
corporation  (hereinafter  "Assignor"),  and BERG & BERG  ENTERPRISES,  INC.,  a
California corporation (hereinafter "Assignee"),  with respect to the assignment
and transfer by Assignor to Assignee of all its right,  title and  interest,  as
lessee, in that certain lease, dated January 6, 1978, as amended by that certain
letter of  clarification,  dated February 17, 1978;  Amendment dated January 30,
1979;  Amendment #2, dated March  17,1979;  and Amendment #3, dated July 1, 1987
(hereinafter the "Lease"),  by and between JOHN A. SOBRATO and SUSAN R. SOBRATO,
as to an undivided forty-five percent (45%) interest,  and CARL E. BERG and MARY
ANN BERG, as to an undivided  forty-five percent (45%) interest,  and ANN RUSSO,
as to a ten percent (10%) interest,  predecessor in interest to CARL E. BERG and
MARY ANN BERG,  Trustees of the Berg Living  Trust UTA dated May 1, 1981;  CLYDE
BERG and NANCY BERG,  Trustees of the Clyde Berg Living Trust UTA dated December
17, 1981; CLYDE BERG,  Trustee of the Carl Berg Child's Trust UTA dated, June 2,
1978  (hereinafter  "Landlord"),  as  lessor  thereunder,  and  TYMSHARE,  INC.,
predecessor in interest of Assignor,  as lessee  thereunder;  and all its right,
title and interest, as sublessor,  in that certain sublease,  dated November 13,
1987  (hereinafter the "Sublease"),  by and between Assignor and Apple computer,
Inc., a California  corporation,  as sublessee  (hereinafter  "Sublessee").  The
subject of both the Lease and Sublease is that certain real property  located in
the City of Cupertino ,County of Santa Clara, State of California,  and commonly
known as 20605,  20665,  and 20705  Valley  Green  Drive,  as more  particularly
described in Exhibit "A" attached hereto and incorporated  herein.  (hereinafter
the "Premises").

WHEREAS,  Assignor and Assignee  have  entered into an  Assignment  of Lease and
Sublease,  with an effective date of June 1, 1993 (the "Assignment") with regard
to the  assignment and the transfer of Assignor's  right,  title and interest in
the Preemies both as Lessee and Sublessor to Assignee;

NOW,  THEREFORE,  Assignor and Assignee  hereby state following for recording in
the public records of the County of Santa Clara, State of California:

1. Assignor  hereby  assigns and transfers to Assignee all its right,  title and
interest,  as both  lessee  and  sublessor,  in the  Premises  (hereinafter  the
"Assignment"), including but not limited to all rights of first refusal, options
to renew the, Lease and option to purchase.

2. All parties to the Assignment  agree that the  Assignment  shall not effect a
merger of the Lease and Sublease.

3. This Memorandum shall incorporate  herein all the terms and provisions of the
Assignment of Lease and Sublease, as though fully set forth herein.

4. This  Memorandum  is made  solely  for  recording  purposes  and shall not be
construed to alter,  modify or supplement  the Assignment of Lease and Sublease.
This  Memorandum  has been recorded only for the purpose of giving notice of the
existence of the Assignment of Lease and Sublease. If there is any inconsistency
between this  Memorandum  and the  Assignment  of Lease and  Sublease,  then the
Assignment of Lease and Sublease shall prevail.

IN WITNESS WHEREOF, this Memorandum is executed this 13th day of July, 1993.

ASSIGNOR:

MCDONNELL DOUGLAS CORPORATION a Maryland corporation,

By /s/ Gerald J. Olsen
Gerald J. Olsen
Its Director of Facilities

ASSIGNEE:

BERG & BERG ENTERPRISES, INC.
a California corporation

By /s/ Carl E. Berg..
CARL E. BERG, its President

Witnessed by /s/ Cheryl A. Chavez





                           FIRST AMENDMENT TO SUBLEASE

This First Amendment to Sublease (the  "Amendment") is dated and effective as of
May 25, 1995 and is made by and between Berg & Berg Enterprises,  Inc. ("Berg"),
a California  corporation,  and Apple  Computer,  Inc.  ("Apple"),  a California
corporation, with reference to the following:

                                    Recitals

A. Pursuant to that certain  sublease dated November 13, 1987 (the  'Sublease"),
McDonnell  Douglas  Corporation  ("MDC"),  as  sublessor,  leased to  Apple,  as
sublessee, that certain property consisting of two buildings and related parking
areas  located at and  commonly  known as 20605  Valley Green Drive (the "Valley
Green 5 Building"),  and 20665 and 20705 Valley Green Drive (the "Valley Green 6
Building"), Cupertino (collectively, the "Premises").

B. The Sublease was made under that certain lease  affecting the Premises  dated
January 6, 1978, by and between John A. Sobrato and Carl E. Berg, and members of
their  respective  families  (collectively,  "Sobrato/Berg"),  as landlord,  and
Tymshare, Inc. a California corporation ("Tymshare"),  as tenant. Said lease was
amended  and/or  supplemented  by the  following  instruments:  (i) letter dated
February 17, 1978,  (ii) Amendment  dated January 30, 1979,  (iii)  Amendment #2
dated March 17, 1979,  and (iv)  Amendment  #3 dated July 1, 1987.  The original
lease  and  all of  said  amendments  or  supplements  are  referred  to  herein
collectively as the "Master Lease".

C. Prior to the date of this Amendment, Mary A. Berg and Carl E. Berg, Trustees,
Clyde Berg and Nancy Berg, Trustees, and Clyde Berg, Trustee (collectively,  the
"Berg  Family  Partnership")  succeeded  to the  interest of Sobrato/  Berg,  as
landlord under the Master Lease.

D.  Prior  to the  date of this  Amendment,  McDonnell  Douglas  Corporation,  a
Maryland corporation ("MDC"),  succeeded to the interest of Tymshare, as tenant,
under the Master Lease, and entered into the Sublease with Apple.

E. By Assignment of Lease and Sublease dated July 13, 1993, MDC assigned all its
right and interest as tenant  under the Master Lease and as sublessor  under the
Sublease to Berg.  The Sublease  continued in full force and effect,  as between
Berg, as sublessor, and Apple, as sublessee.

F. Berg and Apple now wish to extend the term of the Sublease, and to modify and
amend certain provisions of the Sublease,  all as more particularly as set forth
herein:

NOW, THEREFORE, THE PARTIES HERETO MUTUALLY AGREE AS FOLLOWS:

1. EXERCISE OF OPTION FOR EXTENSION OF SUBLEASE TERM.

1.1 The Sublease  currently  provides that the term thereof shall expire (unless
renewed or extended) on December 31,1997.

1.2  Pursuant  to  paragraph  4.2  ("Option  to  Extend  Sublease  Term") of the
Sublease,  Apple has been granted two (2)  consecutive  five (5) year options to
extend the term of the Sublease with respect to the entire Premises.

1.3 By executing this Amendment,  Apple hereby notifies Berg of Apple's exercise
of the first five (5) year  renewal  option (the "First  Option") for the Valley
Green  6  Building.  Berg  and  Apple  expressly  acknowledge  and  agree  that,
notwithstanding  the  provisions of paragraph  4.2 of the Sublease,  Apple shall
have the right to exercise  the First  Option with respect to the Valley Green 6
Building  only,  pursuant to this  Amendment.  Berg and Apple further  expressly
acknowledge  and agree that this notice  shall be  sufficient  to exercise  said
First Option with respect to the Valley  Green 6 Building,  notwithstanding  any
requirement  in the  Sublease  that such notice be given  within a certain  time
period, and Berg hereby accepts such exercise.

1.4 Pursuant to Apple's  exercise of the First Option,  as described  above, the
termination  date of the Sublease,  with respect to the Valley Green 6 Building,
is hereby extended to and including 12:00 o'clock midnight on December 31, 2002.

1.5 Berg hereby  agrees  that Apple  shall have the right to exercise  the First
Option with respect to the Valley Green 5 Building at any time to and  including
12:00 o'clock  midnight on June 30, 1997. Apple shall exercise the First Option,
if at all,  with  respect to the Valley  Green 5 Building by giving Berg written
notice of such exercise,  in the manner provided by the Sublease or as otherwise
mutually  agreed by Berg and Apple.  If Apple so exercises the First Option with
respect  to the Valley  Green 5  Building,  then the  parties  shall  execute an
amendment  to the Sublease  reflecting  such  exercise,  which  amendment  shall
reflect the  inclusion  of the Valley  Green 5 Building in the  Premises for the
First Extended Term (as defined in the Sublease),  at a base monthly rental rate
of One Dollar and Ten Cents ($1.10) per rentable square foot of the Valley Green
5 Building

1.6 Berg represents, warrants and covenants to Apple as follows:

(a) In  consideration  of Apple's  exercise  of the First  Option,  as set forth
above,  Berg shall  exercise its option to extend the term of the Master  Lease,
all as more particularly set forth in subparagraph 4.2(a) of the Sublease.

(b) Berg shall not cause, and shall use its best efforts to ensure that the Berg
Family  Partnership,  as landlord  under the Master Lease,  does not cause,  any
Event of Default  (as that term is defined in the Master  Lease) to occur  under
the Master Lease.

1.7  Notwithstanding  the provisions of subsection 1.5, above,  Apple shall have
all of its rights as set forth in paragraph  4.2 of the Sublease with respect to
any exercise of any options Berg may have, as tenant under the Master Lease,  to
extend the term of the Master Lease.

2. FAILURE OF APPLE TO EXERCISE FIRST OPTION FOR VALLEY GREEN 5 BUILDING.

If Apple does not  exercise  the First Option with respect to the Valley Green 5
Building,  as provided in paragraph 1.5, above, then the following provisions of
this Section 2 shall be applicable and effective.

2.1 Reduction of Premises.

(a) If Apple does not exercise the First Option with respect to the Valley Green
5  Building,  as provided  in  paragraph  1.5,  above,  then the Valley  Green 5
Building shall be deleted from the Sublease,  and no longer  considered  part of
the Premises,  effective as of 12:00 o'clock  midnight on December 31, 1997 (the
"Premises  Reduction  Date").  From and after said Premises  Reduction Date, the
term  "Premises"  shall only refer to the Valley  Green 6  Building,  containing
approximately 121,574 square feet of rentable space.

(b)  Effective  as of the Premises  Reduction  Date,  the square  footage of the
Premises,  as described on the Summary of Sublease Provisions,  shall be amended
from approximately 142,000 square feet to approximately 121,574 square feet.

(c) Apple shall be  responsible  for any  termination  obligations  described in
paragraph 20 of the Sublease  ("Surrender  of Premises")  for the Valley green 5
Building, as required by the Sublease.

2.2. Revised Percentage.

(a) For  purposes of  complying  with the  provisions  of  paragraph  6.1 of the
Sublease,   Apple  and  Berg  acknowledge  and  agree  that  Apple's  applicable
percentage of any and all taxes,  assessments and other charges payable by Apple
thereunder  shall, as of the Premises  Reduction Date, shall be amended from One
Hundred  Percent  (100%) to Eighty Five and  Sixty-Two  One  Hundredths  percent
(85.62%).

 (b) In  addition,  Paragraph  7 of the Master  Lease  ("Parking  Area) shall be
modified, as of the Premises Reduction Date, by reducing Apple's exclusive right
to use One Hundred  Percent  (100%) of the parking area to Eighty Five and Sixty
Two One  Hundredths  Percent  (85.62%) of the total parking  area.  Said reduced
parking area shall be those parking spaces for the Valley Green 6 Building.

2.3 Insurance.

For purposes of complying  with the  provisions  of paragraph 13 of the Sublease
("Insurance"),  Apple and Berg  acknowledge  and agree that  effective as of the
Premises  Reduction  Date Apple shall only be required to provide  insurance for
the Premises,  as reduced  pursuant to this Amendment to wit: the Valley Green 6
Building.

3. BASE RENT DURING OPTION TERM.

3.1  Notwithstanding  any term or  provision  of the  Sublease to the  contrary,
including  without  limitation  the terms and conditions of paragraph 5.2 of the
Sublease, Berg expressly agrees that, unless and until Apple exercises the First
Option with  respect to the Valley  Green 5 Building,  as provided in  paragraph
1.5,  above,  Apple shall pay, as Base Monthly  Rent for the Premises  under the
Sublease for the First  Extended Term (as that term is defined in the Sublease),
the amount of One Hundred Thirty-Three Thousand Seven Hundred Thirty-One Dollars
and Forty Cents ($133,731.40) per month.

3.2 If and only if Apple  exercises  the First Option with respect to the Valley
Green 5 Building,  Apple shall pay, as Base Monthly Rent for the Premises  under
the Sublease for the First Extended  Term,  the amount of One Hundred  Fifty-Six
Thousand Two Hundred Dollars ($156,200.00) per month.

4. REPLACEMENT OF HVAC EQUIPMENT.

4.1 Berg and Apple agree that the  existing  roof-top  heating  and  ventilating
units (the "VAV HVAC" units) on the Valley Green 6 Building need to be replaced.

4.2 It is  hereby  agreed  that  Berg  shall  provide  Apple  with an  equipment
improvement  fund,  in an amount  not to exceed  Seven  Hundred  Fifty  Thousand
Dollars ($750,000) (hereinafter referred to as the "Fund Amount"),  which amount
shall be used to reimburse  Apple for costs incurred in connection with the work
of installing four (4) new VAV HVAC units  (hereinafter  referred to as "Work").
(See  Specification Book and Drawings  consisting of 14 pages (0.00,  M0.1-M0.2,
M1.1-M1.2, M1.4-M1.6, M6.1, M9.1, E1.1-1.2 and S1.1-S1.2) dated May 24, 1995 and
prepared by ENCO Energy Conservation Company, attached hereto as Exhibit "A" and
incorporated herein by this reference.)

4.3 The scope of the Work shall include:  (i) structural and engineering design,
(ii) purchasing  mechanical  equipment consisting of four (4) VAV HVAC units (75
tons  each for a total  of 300  tons)  (collectively,  the  "Equipment"),  (iii)
structural  roof work,  (iv) labor and  installation  of the Equipment,  and (v)
modifications to the existing duct work.

4.4 Apple shall hire all  contractors for the prosecution of the Work, and shall
manage the Work. Apple shall pay for all Work,  subject to Berg's  obligation to
reimburse  Apple for such  costs,  as set forth in Section 5 of this  Amendment,
below.  Upon completion of the Work, Apple shall submit to Berg proof that Apple
has paid for the Work  (including  true and correct  copies of all paid invoices
for the Work),  and Berg shall  promptly  reimburse  Apple for the amount of all
such invoices, in an amount not exceeding the Fund Amount.

4.5 Both parties agree that portions of the Work have already  commenced and the
estimated completion date is September 15,1995.

5. REPAYMENT.

5.1 Apple and Berg agree that Berg, as landlord, shall be entitled to recapture,
and shall recapture, a portion of the cost of the Work through periodic payments
from Apple to Berg, as set forth in this Section 5.

5.2 The total  cost of the Work will be  amortized  over a ten (10) year  period
(which is the deemed useful life of the improvements which constitute the Work),
with an annual interest rate of ten percent (10%).

5.3 Commencing on a date to be determined as set forth in Paragraph 5.5,  below,
Apple will, during the remaining term of the Sublease  (including any further or
additional option,  extension or renewal periods), make monthly payments to Berg
in accordance with the attached amortization  schedule,  which schedule is based
on the Fund  Amount.  Based on the Fund  Amount  and the  attached  amortization
schedule,  the  additional  monthly rent required to be paid by Apple to Berg is
Nine Thousand Nine Hundred Twelve Dollars  ($9,912.00),  hereinafter referred to
as the  "Repayment  Amount".  This  Repayment  Amount will be included  with the
monthly base rent otherwise due and payable under the Sublease.

5.4 If the actual total cost of the Work is less than the Fund Amount,  then the
schedule will be modified to equal the amount of the actual cost of the Work. It
is mutually agreed by both parties that the methodology  used in calculating any
revised  monthly  payments which may be due if the cost of the Work is less than
the Fund Amount will be the same as the attached amortization  schedule. In such
event,  Berg shall provide a revised  amortization  schedule based on the actual
cost of the Work and it shall specify the revised  monthly payment to be paid by
Apple.

5.5 The start date for commencement of the amortization of the Work shall be the
first day of the month following  reimbursement by Berg to Apple, as provided in
Paragraph 5.4, above.  Apple and Berg shall mutually agree upon the amortization
commencement  date.  5.6 If the Sublease  (as it may be renewed or extended,  in
Apple's  discretion and pursuant to the terms of the Sublease)  expires prior to
the expiration of the ten year amortization  period,  then Apple's obligation to
pay the monthly  Repayment  Amount shall cease as of the  expiration  date,  and
Apple  shall  thereafter  have no further  liability  to Berg for payment of any
portion of the amortized amount.

6. EFFECT OF AMENDMENT: RATIFICATION OF SUBLEASE.

Except as modified by this Amendment, the Sublease is hereby ratified,  approved
and confirmed upon all of the original terms and conditions.

IN WITNESS  WHEREOF,  the parties have executed this  Amendment on the dates set
forth below, to be effective as set forth above.

BERG & BERG ENTERPRISES, a California corporation
By: /s/ Carl E. Berg
Printed Name: Carl E. Berg
Title: Pres.
Date: 8/2/95

APPLE COMPUTER, INC., a California corporation
By: /s/ Joseph A. Graziano
Printed Name: Joseph A. Graziano
Title: Executive Vice President and Chief Financial Officer
Date: 7/31/95





                            CONSENT OF MASTER LESSOR

The  undersigned,  as landlord  under the Master  Lease,  hereby  consent to the
foregoing  First  Amendment to Sublease,  on the terms and  conditions set forth
therein.

CARL E. BERG and MARY ANN BERG, Trustees for Berg Living Trust
UTA dated
May 1, 1981, as to an undivided 81% interest

/s/ Carl E. Berg
CARL E. BERG

/s/ Mary Ann Berg by Carl E. Berg, her Attorney in Fact
MARY ANN BERG

CLYDE BERG and NANCY BERG,  Trustees  of the Clyde Berg  Living  Trust UTA dated
December 17, 1981, as to an undivided 11.83% interest

/s/ Clyde Berg by Carl E. Berg, his Attorney in Fact
CLYDE BERG

/s/ Nancy by Carl E. Berg, her Attorney in Fact
NANCY BERG

CLYDE BERG,  Trustee of Carl Berg Child's Trust UTA dated June 1, 1978, as to an
undivided 7.16% interest

/s/ Clyde Berg
CLYDE BERG





                                 Interest Vision

                      Sample Amortization Schedule - Apple

Loan or Annuity Variables:



                                                
Start Date:      Jun 1, 1995    End Date:            Jun 1, 2005
Start Payment:   Jun 1, 1995    No. of Payments:     120
Start Interest:  Jun 1, 1995    Interest Rate:       10.000%
Payment Freq.:   Monthly        Initial Principal:   $750000.00
Compound Freq.:  Monthly        Payment Amount:      $9912.33
Days in Mo./Yr.: Actual No.     Balloon:             $0.00
Payment Mode:    In Arrears     Amortization Method: Simple Int.




                    Payment    Interest  Interest
No.  Date            Amount      Amount   Rate/Yr.  Principal     Balance
                                              
     Jun 1, 1995       0.00        0.00     0.000        0.00   750000.00
 1   Jul 1, 1995    9912.33     6164.38    10.000     3747.94   746252.06
 2   Aug 1, 1995    9912.33     6338.03    10.000     3574.30   742677.76
 3   Sep 1, 1995    9912.33     6307.67    10.000     3604.65   739073.10
 4   Oct 1, 1995    9912.33     6074.57    10.000     3837.76   735235.35
 5   Nov 1, 1995    9912.33     6244.46    10.000     3667.86   731567.48
 6   Dec 1, 1995    9912.33     6012.88    10.000     3899.45    27668.04
SUBTOTAL:          59473.97    37142.01              22331.96
 7   Jan 1, 1996    9912.33     6163.31    10.000     3749.02   723919.02
 8   Feb 1, 1996    9912.33     6131.55    10.000     3780.77   720138.25
 9   Mar 1, 1996    9912.33     5706.01    10.000     4206.32   715931.93
10   Apr 1, 1996    9912.33     6063.90    10.000     3848.42   712083.51
11   May 1, 1996    9912.33     5836.75    10.000     4075.58   708007.03
12   Jun 1, 1996    9912.33     5996.79    10.000     3915.54   704092.39
13   Jul 1, 1996    9912.33     5771.25    10.000     4141.08   699951.31
14   Aug 1, 1996    9912.33     5928.55    10.000     3983.78   695967.53
15   Sep 1, 1996    9912.33     5894.81    10.000     4017.52   691950.01
16   Oct 1, 1996    9912.33     5671.72    10.000     4240.61   687709.40
17   Nov 1, 1996    9912.33     5824.86    10.000     4087.47   683621.93
18   Dec 1, 1996    9912.33     5603.46    10.000     4308.87   679313.06
SUBTOTAL:         116947.94    70592.97              48354.98
19   Jan 1, 1997    9912.33     5769.51    10.000     4142.82   675170.24
20   Feb 1, 1997    9912.33     5734.32    10.000     4178.01   670992.24
21   Mar 1, 1997    9912.33     5147.34    10.000     4764.99   666227.25
22   Apr 1, 1997    9912.33     5658.37    10.000     4253.96   661973.29
23   May 1, 1997    9912.33     5440.88    10.000     4471.45   657501.83
24   Jun 1, 1997    9912.33     5584.26    10.000     4328.07   653173.77
25   Jul 1, 1997    9912.33     5368.55    10.000     4543.78   648629.99
26   Aug 1, 1997    9912.33     5508.91    10.000     4403.42   644226.57
27   Sep 1, 1997    9912.33     5471.51    10.000     4140.82   639785.76
28   Oct 1, 1997    9912.33     5258.51    10.000     4653.82   635131.94
29   Nov 1, 1997    9912.33     5394.27    10.000     4518.06   630613.89
30   Dec 1, 1997    9912.33     5183.13    10.000     4729.20   625884.69
SUBTOTAL:         118947.94     5519.56              53428.38
31   Jan 1, 1998    9912.33     5315.73    10.000     4596.60   621288.09
32   Feb 1, 1998    9912.33     5276.69    10.000     4635.64   616652.45
33   Mar 1, 1998    9912.33     4730.48    10.000     5181.84   611470.61
34   Apr 1, 1998    9912.33     5193.31    10.000     4719.02   606751.59
35   May 1, 1998    9912.33     4987.00    10.000     4925.33   601826.27
36   Jun 1, 1998    9912.33     5111.40    10.000     4800.93   597025.34
37   Jul 1, 1998    9912.33     4907.06    10.000     5005.27   592020.07
38   Aug 1, 1998    9912.33     5028.12    10.000     4884.21   587135.85
39   Sep 1, 1998    9912.33     4986.63    10.000     4925.70   582210.16
40   Oct 1, 1998    9912.33     4785.29    10.000     5127.04   577083.12
41   Nov 1, 1998    9912.33     4901.25    10.000     5011.07   572072.04
42   Dec 1, 1998    9912.33     4701.96    10.000     5210.37   566861.68
SUBTOTAL:         118947.94     9924.93              59023.01
43   Jan 1, 1999    9912.33     4814.44    10.000     5097.89   561763.79
44   Feb 1, 1999    9912.33     4771.14    10.000     5141.18   556622.61
45   Mar 1, 1999    9912.33     4269.98    10.000     5642.35   550980.26
46   Apr 1, 1999    9912.33     4679.56    10.000     5232.77   545747.49
47   May 1, 1999    9912.33     4485.60    10.000     5426.73   540320.76
48   Jun 1, 1999    9912.33     4589.03    10.000     5323.30   534997.45
49   Jul 1, 1999    9912.33     4397.24    10.000     5515.09   529482.37
50   Aug 1, 1999    9912.33     4496.97    10.000     5415.35   524067.01
51   Sep 1, 1999    9912.33     4450.98    10.000     5461.35   518605.66
52   Oct 1, 1999    9912.33     4262.51    10.000     5649.82   512955.85
53   Nov 1, 1999    9912.33     4356.61    10.000     5555.72   507400.13
54   Dec 1, 1999    9912.33     4170.41    10.000     5741.92   501658.21
SUBTOTAL:         118947.94    53744.48              65203.41
55   Jan 1, 2000    9912.33     4249.02    10.000     5663.31   495994.90
56   Feb 1, 2000    9912.33     4201.05    10.000     5711.28   490283.62
57   Mar 1, 2000    9912.33     3884.76    10.000     6027.57   484256.05
58   Apr 1, 2000    9912.33     4101.62    10.000     5810.71   478445.35
59   May 1, 2000    9912.33     3921.68    10.000     5990.65   472454.70
60   Jun 1, 2000    9912.33     4001.67    10.000     5910.66   466544.04
61   Jul 1, 2000    9912.33     3824.13    10.000     6088.20   460455.84
62   Aug 1, 2000    9912.33     3900.04    10.000     6012.29   454443.55
63   Sep 1, 2000    9912.33     3849.11    10.000     6063.22   448380.33
64   Oct 1, 2000    9912.33     3675.25    10.000     6237.08   442143.25
65   Nov 1, 2000    9912.33     3744.93    10.000     6167.40   435975.86
66   Dec 1, 2000    9912.33     3573.57    10.000     6338.76   429637.10
SUBTOTAL:         118947.94    46926.83              72021.11
67   Jan 1, 2001    9912.33     3648.97    10.000     6263.36   423373.74
68   Feb 1, 2001    9912.33     3595.78    10.000     6316.55   417057.19
69   Mar 1, 2001    9912.33     3199.34    10.000     6712.99   410344.21
70   Apr 1, 2001    9912.33     3485.12    10.000     6427.21   403916.99
71   May 1, 200,    9912.33     3319.87    10.000     6592.46   397324.53
72   Jun 1, 2001    9912.33     3374.54    10.000     6537.79   390786.74
73   Jul 1, 2001    9912.33     3211.95    10.000     6700.38   384086.36
74   Aug 1, 2001    9912.33     3262.10    10.000     6650.23   377436.13
75   Sep 1, 2001    9912.33     3205.62    10.000     6706.71   370729.42
76   Oct 1, 2001    9912.33     3047.09    10.000     6865.24   363864.19
77   Nov 1, 2001    9912.33     3090.35    10.000     6821.98   357042.21
78   Dec 1, 2001    9912.33     2934.59    10.000     6977.73   350064.48
SUBTOTAL:         118947.94    39375.32              79572.62
79   Jan 1, 2002    9912.33     2973.15    10.000     6939.18   343125.30
80   Feb 1, 2002    9912.33     2914.21    10.000     6998.11   336127.18
81   Mar 1, 2002    9912.33     2578.51    10.000     7333.82   328793.37
82   Apr 1, 2002    9912.33     2792.49    10.000     7119.84   321673.53
83   May 1, 2002    9912.33     2643.89    10.000     7268.44   314405.09
84   Jun 1, 2002    9912.33     2670.29    10.000     7242.04   307163.05
85   Jul 1, 2002    9912.33     2524.63    10.000     7387.70   299775.35
86   Aug 1, 2002    9912.33     2546.04    10.000     7366.29   292409.06
87   Sep 1, 2002    9912.33     2483.47    10.000     7428.85   284980.21
88   Oct 1, 2002    9912.33     2342.30    10.000     7570.03   277410.18
89   Nov 1, 2002    9912.33     2356.09    10.000     7556.24   269853.94
90   Dec 1, 2002    9912.33     2217.98    10.000     7694.35   262159.59
SUBTOTAL:         118947.94    31043.06              87904.89
91   Jan 1, 2003    9912.33     2226.56    10.000     7685.77   254473.82
92   Feb 1, 2003    9912.33     2161.28    10.000     7751.04   246722.78
93   Mar 1, 2003    9912.33     1892.67    10.000     8019.66   238703.12
94   Apr 1, 2003    9912.33     2027.34    10.000     7884.99   230818.13
95   May 1, 2003    9912.33     1897.14    10.000     8015.19   222802.94
96   Jun 1, 2003    9912.33     1892.30    10.000     8020.03   214782.91
97   Jul 1, 2003    9912.33     1765.34    10.000     8146.99   206635.92
98   Aug 1, 2003    9912.33     1754.99    10.000     8157.34   198478.58
99   Sep 1, 2003    9912.33     1685.71    10.000     8226.62   190251.96
100  Oct 1, 2003    9912.33     1563.71    10.000     8348.61   181903.35
101  Nov 1, 2003    9912.33     1544.93    10.000     8367.40   173535.95
102  Dec 1, 2003    9912.33     1426.32    10.000     8486.01   165049.94
SUBTOTAL:         116947.94    21838.30              97109.65
103  Jan 1, 2004    9912.33     1397.96    10.000     8514.36   156535.58
104  Feb 1, 2004    9912.33     1325.85    10.000     8586.48   147949.10
105  Mar 1, 2004    9912.33     1172.27    10.000     8740.05   139209.04
106  Apr 1, 2004    9912.33     1179.09    10.000     8733.24   130475.81
107  May 1, 2004    9912.33     1069.47    10.000     8842.85   121632.95
108  Jun 1, 2004    9912.33     1030.22    10.000     8882.10   112750.85
109  Jul 1, 2004    9912.33      924.19    10.000     8988.14   103762.71
110  Aug I, 2004    9912.33      878.86    10.000     9033.46    94729.25
111  Sep 1, 2004    9912.33      802.35    10.000     9109.98    85619.27
112  Oct 1, 2004    9912.33      701.80    10.000     9210.53    76408.74
113  Nov 1, 2004    9912.33      647.18    10.000     9265.15    67143.59
114  Dec 1, 2004    9912.33      550.36    10.000     9361.97    57781.62
SUBTOTAL:         118947.94    11679.61             107268.33
115  Jan 1, 2005    9912.33      490.75    10.000     9421.58    48360.03
116  Feb 1, 2005    9912.33      410.73    10.000     9501.60    38858.44
117  Mar 1, 2005    9912.33      298.09    10.000     9614.24    29244.20
118  Apr 1, 2005    9912.33      248.38    10.000     9663.96    19580.25
119  May 1, 2005    9912.33      160.93    10.000     9751.39     9828.85
120  Jun 1, 2005    9912.33       83.48    10.000     9828.85        0.00
SUBTOTAL:          59473.97     1692.36              57781.62
GRAND TOTAL:     1189479.42   439479.42             750000.00






                            THIRD AMENDMENT TO LEASE

This Third Amendment to Lease ("Amendment"),  is made and entered into this 15th
day of May, 1996 by and between Berg Family Partnership ("Berg" or "Lessor") and
Apple Computer, Inc. ("Apple" or "Lessee'), a California corporation.

RECITALS

A. Apple currently  leases from Berg  approximately  23,400 square feet of space
located at 10300 Bubb Road,  Cupertino,  California (the "Premises') pursuant to
that certain lease dated October 6, 1987,  that certain  lease  amendment  dated
January 11, 1988,  that certain  lease  amendment  dated May 31, 1991,  and that
certain lease amendment dated December, 1992 (collectively referred to herein as
the "Lease).

B. The term of the Lease expires on November 30, 1996.

C.  Apple  has  elected  and Berg has  agreed to extend  the Lease  pursuant  to
Paragraph 2 of that certain lease amendment dated December,  1992 subject to the
terms and conditions set forth herein:

NOW, THEREFORE, the parties hereto agree to amend the Lease as follows:

1.  TERM: The term of the Lease is hereby extended for two (2)
years until November 30, 1998.

2. BASIC  RENT:  The basic  monthly  rent shall be  adjusted  to and  payable as
follows:


                                                
December 1, 1996 through November 30, 1997     $29,250
December 1, 1997 through November 30, 1998     $29,952


3. OPTION TO EXTEND:  Berg hereby grants Apple one (1) option (the  "Option') to
extend the term of the Lease for a period of two (2) years (the  "Option  Term')
on the following terms and conditions:

      (i) Lessee shall give Lessor  written notice of its exercise of its Option
      no later than June 1, 1998.

      (ii) Lessee may not exercise the Option if Lessee is in default  according
      to the terms and conditions of the Lease.

      (iii) All term and conditions of the Lease and this Amendment  shall apply
      during the Option Term.

      (iv) Rent for the  Premises  during  the  Option  Term shall be payable in
      advance  on the first  day of each  calendar  month at 95% of fair  market
      value,  but not more than $1.32 per square foot per month during the first
      year of the  Option  Term and $1.35 per square  foot per month  during the
      second year of the Option Term.

4.  RATIFICATION  OF  LEASE:  Except  as  modified  herein,  the Lease is hereby
ratified, approved and confirmed upon all the terms, covenants, and conditions.

BERG FAMILY PARTNERSHIP
a California general partnership

By: /s/ Carl E. Berg
Carl E. Berg
Title: General Partner
Date: 6/5/96

APPLE COMPUTER, INC.
a California Corporation

/s/ George Scalise
George Scalise
Title: Executive Vice President, Chief Administrative Officer
Date: 6/14/96





October 21, 1996

Mr. Carl E. Berg
De Alma Boulevard Investment and Berg & Berg Developers
10050 Bandley Drive
Cupertino, CA 95014

Re: Lease dated March 24, 1989 between De Anza Boulevard  Investment,  a Limited
Partnership and Berg & Berg Developers a California Partnership ("Landlord") and
Apple  Computer,  Inc., a  California  corporation  ("Tenant")  for the Premises
located at 10500 North De Anza Boulevard, Cupertino, CA 95014

Dear Carl:

Pursuant to  Paragraph  2.2 of the above  referenced  Lease  ("Options to Extend
Lease Term"),  Tenant hereby exercises its first (1st) option to extend the term
of the lease for an additional  five (5) year term  commencing  June 1, 1997 and
ending May 31, 2002. As stipulated in subparagraph  2.2 C of the Lease, the base
monthly for this first  option will be Three  Hundred  Sixty One  Thousand  Five
Hundred Seventy Dollars  ($361,570) per month. All other terms and conditions of
the Lease shall remain the same.

Please sign both copies of this letter acknowledging  receipt of this notice and
return one signed  counterpart  to Apple,  to the  attention of Robert A. Hecox,
Vice President, RAM Estate. Construction & Facilities at the address below, Mail
Stop 76-AOK.

Very truly yours, Acknowledged and Agreed:
APPLE COMPUTER, INC.,
a California corporation

/s/ G. F. Amelio
Dr. Gilbert F. Amelia
Chief Operating Officer
Date: 11-14-96

Acknowledged and Agreed:

De Anza Boulevard Investment,
a Limited Partnership

/s/ Carl E. Berg
Carl E. Berg, Trustee of the Carl E. Berg Revocable Trust
Date: 11/20/96

Berg & Berg Developers,
a California Partnership

/s/ Carl E. Berg
Carl E. Berg, General Partner
Date: 11/20/96





June 18, 1997

Berg & Berg Enterprises, Inc.
10050 Bandley Drive
Cupertino, California 95014

Attention: Mr. Carl E. Berg

RE:  SUBLEASE DATED NOVEMBER 13, 1987 BETWEEN BERG & BERG  ENTERPRISES,  INC., A
CALIFORNIA CORPORATION,  AS SUCCESSOR TO McDONNELL DOUGLAS CORPORATION ("BERG"),
ON THE ONE HAND, AND APPLE COMPUTER,  INC. ("APPLE"), ON THE OTHER HAND, FOR THE
PREMISES  LOCATED AT 20605  VALLEY  GREEN DRIVE  (VALLEY  GREEN 5) AND 20665 AND
20705 VALLEY (GREEN DRIVE ("VALLEY GREEN 6"), CUPERTINO, CALIFORNIA 95014

Ladies and Gentlemen:
Pursuant to Paragraph 1.5 ("Exercise of Option for Extension of Sublease  Term")
of the First  Amendment  to the  Sublease,  dated  May 25,  1995,  Apple  hereby
exercises  its first option to extend the term of the  Sublease  with respect to
the Valley Green 5 Premises,  for an  additional  five (5) year term  commencing
January 1, 1998 and ending December 31, 2002.

Pursuant to said Paragraph 1.5, the base monthly rent for this first option will
be One Dollar and Ten Cents  ($1.103  per  rentable  square  foot for the Valley
Green 5 premises,  which the parties  agree is a Twenty  Thousand  Four  Hundred
Twenty-Six  (20,426)  square foot building,  for a total of Twenty-Two  Thousand
Four Hundred  Sixty-Eight  Dollars and Sixty Cents  ($22,468.60)  per month. All
other terms and conditions of the Sublease shall remain the same.

Please sign both copies of this letter  acknowledging  receipt and approval this
notice of exercise, and return one signed counterpart to Apple, to the attention
of Robert A. Hecox,  Vice President,  Real Estate,  Construction & Facilities at
the address below, Mail Stop 76-AOK.

Very truly yours,

APPLE COMPUTER, INC., a California corporation, as Subtenant

/s/ Fred D. Anderson
Fred D. Anderson
Executive Vice President and Chief Financial Officer
Date: 6/20/97

Acknowledged and Agreed:
BERG & BERG ENTERPRISES, INC., a California corporation, as
Sublessor

/s/ Carl E. Berg
Carl E. Berg
President
Date: 6/24/97

Acknowledged and Agreed:
Berg Family Partnership, as Master Lessor

By: Carl E. Berg and Mary Ann Berg, Trustee for Berg Living
Trust, UTA dated May 1,1981, as to an undivided 81.01% interest

/s/ Carl E. Berg
CARL E. BERG

/s/ Mary Ann Berg
MARY ANN BERG

By: Clyde Berg and Nancy Berg, Trustees of the Clyde Berg Living
Trust UTA dated December 17,1981, as to an undivided 11.83%
interest

/s/ Clyde Berg
CLYDE BERG

/s/ Nancy Berg
NANCY BERG

By: Clyde Berg, Trustee of Carl Berg Child's Trust UTA dated June
1, 1978, as to an undivided 7.16% interest

/s/ Clyde Berg
CLYDE BERG