AGREEMENT CONCERNING ASSIGNMENT OF LEASES

         THIS AGREEMENT  ("Agreement") is made for reference purposes only as of
June  5,  1996,  between  PINNACLE  SYSTEMS,   INC.,  a  California  corporation
("Assignee"),  and NETWORK  COMPUTING  DEVICES,  INC., a California  corporation
("Assignor").

                                   BACKGROUND

         A. Assignor, Assignee and D.R. Stephens & Company, a California limited
partnership  ("Lessor"),  have entered into that certain Agreement to Assign and
Modify  Leases  of even  date  herewith  (the  "Assignment")  providing  for the
assignment    to   Assignee    and    modification    of   that   (i)   Standard
Industrial/Commercial  Single-Tenant Lease-Net (the "280A Lease") between Lessor
and  Assignor  dated  August 18, 1992 for  approximately  53,300  square feet of
premises located at 280(A) North Bernardo Avenue, Mountain View, California (the
"280A  Premises"),   and  (ii)  Standard   Industrial/Commercial   Single-Tenant
Lease-Net  (the "280B Lease")  between Lessor and Assignor dated August 18, 1992
for  approximately  53,160  square  feet of  premises  located  at 280(B)  North
Bernardo Avenue, Mountain View, California (the "280B Premises"),  each dated as
of August 18, 1992. The 280A and 280B Leases are collectively referred to herein
as the "Leases";  the 280A and 280B Premises are collectively referred to herein
as the "Premises".

         B. Assignor and Assignee  desire to enter into this Agreement to define
their mutual  rights and  obligations  with respect to the  Assignment;  in this
regard,  this  Agreement is intended to supplement and expand upon the terms and
conditions of the Assignment.

         NOW,  THEREFORE,  in consideration of the premises and mutual covenants
set forth in this Agreement, the parties hereto agree as follows:

         1.  Assignor's  Representations.  On the  Effective  Date  (as  defined
below),  and again as of the  closing  date of the  Assignment  (as  defined  in
Paragraph 3 of the Assignment, and hereafter referred to as the "Closing Date"),
Assignor  represents  to  Assignee  that  to  the  best  of its  current  actual
knowledge:  (i) that the Leases are in full force and effect,  and there  exists
under the Leases no "Breach" or "Default" by either Lessor or Assignor,  nor has
there occurred any event which,  with the giving of notice or passage of time or
both,  could  constitute  such a Default  or  Breach;  (ii)  that the  Premises,
including  all  buildings  located  thereon (a) conform to all  requirements  of
covenants,   conditions,   restrictions   and   encumbrances   ("CC&R's"),   all
underwriter's requirements,  and all rules, regulations,  statutes,  ordinances,
laws and building codes,  (collectively,  "Laws") then in effect, and (b) are in
good  operating  condition  and repair  and the  electrical,  mechanical,  HVAC,
plumbing,  elevator and other systems serving the Premises are in good operating
condition  and repair;  (iii) that there are no pending or  threatened  actions,
suits or proceedings before any court or administrative agency against Lessor or
against  Assignor or third  parties  which could,  in the  aggregate,  adversely
affect the  Premises  or any part  thereof or the ability of Assignee to perform
its obligations  under the Leases or of Lessor to perform its obligations  under
the Leases; (iv) that there is no pending or threatened  condemnation or similar
proceeding  affecting the Premises or any portion thereof; (v) that Assignor has
not  received  any  notice  from  any  insurance   company  of  any  defects  or
inadequacies in

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the Premises or any part thereof which could adversely  affect the  insurability
of the Premises or the premiums for the  insurance  thereof;  (vi) that,  (a) no
Hazardous Material is present on or about the Premises,  or, except as otherwise
set forth in that certain Phase 1 Environmental  Site Assessment  dated July 29,
1996, prepared by Secor International  Incorporated for Assignor with respect to
the premises located at 303 Ravendale Drive, Mountain View, California, adjacent
to the Premises,  or the soil,  surface  water or  groundwater  thereof,  (b) no
underground storage tanks or asbestos-containing  building materials are present
on the  Premises,  and  (c) no  action,  proceeding,  or  claim  is  pending  or
threatened  regarding the Premises concerning any hazardous material or pursuant
to any environmental law. As used in this Agreement,  "Hazardous Material" shall
mean  any  material  which is now or  hereafter  regulated  by any  governmental
authority or which poses a hazard to the environment or human life.

         2.  Early  Entry of  Premises.  Save for the  portion  of the  Premises
("Subleased  Premises") identified in that certain sublease between Assignor and
Assignee attached to the Agreement (the "Sublease"),  on or before June 1, 1996,
Assignor  shall vacate and leave the Premises in good  operating  condition  and
repair,  clean and free of debris and any  personal  property of  Assignor,  and
provide  Assignee,  its agents,  employees,  contractors and  consultants,  with
unrestricted,  rent and operating expense free, access to the Premises,  for the
purpose of  installing  the tenant  improvements  described  in Exhibit 1 to the
Assignment.  Except to the extent  caused by any act,  omission,  negligence  or
wilful  misconduct  of  Assignor  or its  employees  or agents,  Assignee  shall
protect, indemnify,  defend, and hold harmless Assignor from and against any and
all claims, demands, causes of action and liabilities arising out of or relating
to Assignee's (or its employees',  agents',  contractors' or consultants') early
entry upon the Premises pursuant to this Paragraph 2.

         3. Access to the  Premises.  In addition to the early entry  rights set
forth in Paragraph 2,  Assignor  shall allow  Assignee,  its agents,  employees,
contractors and consultants, reasonable access to the Premises to engage in such
examinations  and inspections of the Premises as Assignor may reasonably  desire
in  connection  with the  Assignment.  Except to the  extent  caused by any act,
omission,  negligence  or wilful  misconduct  of  Assignor or its  employees  or
agents,  Assignee shall protect,  indemnify,  defend, and hold harmless Assignor
from and against any and all claims,  demands,  causes of action and liabilities
arising  out  of  or  relating  to  Assignee's  (or  its  employees',   agents',
contractors' or consultants')  examinations or inspections of the Premises prior
to the Closing Date.

         4. Proration of Utility and Other Charges.  All utility  charges,  real
estate  taxes and any other  periodic  charges  due  under the  Leases  shall be
prorated by Assignor  and  Assignee as of the Closing  Date.  If the  prorations
cannot  be  accurately  calculated  on the  Closing  Date,  then  they  shall be
calculated  as soon  thereafter  as is  feasible,  and any sums owed  shall bear
interest  at the rate of ten  percent  (10%)  per  annum or the  highest  amount
allowed by law,  whichever  is less,  if payment is not made by the  responsible
party within ten (10) days after its receipt of a bill for any amounts owed.

         5.       Indemnity.

                  A.  Assignor's   Indemnity.   In  amplification   and  not  in
restriction of Assignor's  other indemnity  obligations to Assignee  (including,
without limitation, Assignor's indemnity

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obligations under the Sublease),  Assignor shall indemnify, defend (with counsel
reasonably  acceptable to Assignee),  protect and hold harmless Assignee and its
officers,  employees,  shareholders,  agents and  assigns  from and  against all
claims,  demands,  losses,  costs  (including  attorney's  fees  and  costs)  or
liabilities (i) under the Leases (including,  without limitation,  all liability
due to the presence of  Hazardous  Materials on or about the Premises in any way
caused by Assignor, its employees,  agents or contractors),  or as a consequence
of Assignor's  breach or default of the  obligations on its part to be performed
under the Leases,  accruing on or before the Closing  Date,  (ii)  arising  from
Assignor's  use or occupancy of the Premises on or before the Closing Date,  and
(iii) arising from the breach of any of Assignor's  covenants or representations
to  Assignee  under this  Agreement  or the  Assignment,  regardless  of whether
Assignee has waived any of the conditions set forth in Paragraph 2(b) or 2(e) of
the  Assignment.  The  foregoing  provisions  shall  survive the  expiration  or
termination of the Leases, this Agreement or the Assignment.

         B. Assignee's Indemnity. Assignee shall indemnify, defend (with counsel
reasonably  acceptable to Assignee),  protect and hold harmless Assignor and its
officers,  employees,  shareholders,  agents and  assigns  from and  against all
claims,  demands,  causes of action, costs (including attorney's fees and costs)
or  liabilities  (i)  under  the  Leases  (including,  without  limitation,  all
liability  due to the presence of  Hazardous  Materials on or about the Premises
caused by Assignee or any of its agents or employees) accruing at any time after
the Closing Date, except as otherwise provided in the Sublease,  or (ii) arising
from the breach of any of Assignee's  covenants or  representations  to Assignor
under this Agreement or the Assignment.  The foregoing  provisions shall survive
the expiration or termination of the Leases, this Agreement or the Assignment.

         6. Effective  Date.  This Agreement  shall not be effective  unless and
until both  Assignor and Assignee  have  executed  this  Agreement  and each has
received a fully executed original copy thereof. The date by which the foregoing
shall have occurred is referred to herein as the "Effective Date".

         7.  Miscellaneous.  Should any provisions of this Agreement prove to be
invalid or illegal, such invalidity or illegality shall in no way affect, impair
or invalidate any other provision  hereof,  and such remaining  provisions shall
remain in full force and  effect.  Time is of the  essence  with  respect to the
performance of every provision of this Agreement in which time of performance is
a factor. The captions used in this Agreement are for convenience only and shall
not be considered in the construction or interpretation of any provision hereof.
This Agreement may be executed in  counterparts,  each of which shall constitute
an original and all of which together  shall  constitute  one  instrument.  This
Agreement shall apply to and bind the respective heirs,  successors,  executors,
administrators  and assigns of Assignor and Assignee.  This  Agreement  shall be
construed and enforced in accordance  with the laws of the State of  California.
The language in all parts of this Agreement shall in all cases be construed as a
whole  according to its fair  meaning,  and not  strictly for or against  either
Assignor  or  Assignee.  When a  party  is  required  to do  something  by  this
Agreement,  it  shall  do so at its  sole  cost  and  expense  without  right of
reimbursement  from the other party unless specific  provision is made therefor.
Assignor  shall not  become or be deemed a  partner  nor a joint  venturer  with
Assignee by reason of the provisions of this Agreement.  No subsequent change or
addition to this Agreement  shall be binding unless in writing and signed by the
parties hereto.

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         8. Interpretation. The parties hereto intend that the provisions of the
Assignment and this Agreement will not conflict, and that this Agreement and the
Assignment  shall be construed  harmoniously  so as to give effect to all of the
terms,  covenants  and  conditions of both  documents.  If there is any conflict
between the terms and conditions of this Agreement and the  Assignment,  then as
between Assignor and Assignee,  the terms and conditions of this Agreement shall
control.

         IN WITNESS  WHEREOF,  this  Agreement  is executed as of the date first
above written.

ASSIGNOR:                                    ASSIGNEE:
NETWORK COMPUTING DEVICES, INC.,             PINNACLE SYSTEMS, INC.,
a California corporation                     a California corporation

By:      /s/ Jack Bradley                    By:   /s/ Arthur Chadwick
   -----------------------------                -----------------------------
Printed                                      Printed
Name: Jack Bradley                           Name:  Arthur Chadwick
     ---------------------------                  ---------------------------
Its:     CFO                                 Its:     CFO
    ----------------------------                 ----------------------------


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