INTEGRATED SYSTEMS, INC.
                             1988 Stock Option Plan
                          As Adopted September 26, 1988
                         As Amended through March 28, 1997



         1. PURPOSE.  This Stock Option Plan ("Plan") is  established to provide
incentive for selected persons to promote the financial  success and progress of
Integrated  Systems,  Inc. (the  "Company") by granting such persons  options to
purchase shares of common stock of the Company.

         2. ADOPTION AND  SHAREHOLDER  APPROVAL.  This Plan shall be approved by
the shareholders of the Company, in any manner permitted by applicable corporate
law,  within twelve (12) months before or after the date this Plan is adopted by
the  Board of  Directors  of the  Company  (the  "Board")  and after the date of
certain  amendments to the Plan.  In addition,  no later than twelve (12) months
after the Company  becomes  subject to Section 16(b) of the Securities  Exchange
Act of 1934,  as amended (the  "Exchange  Act") the Company will comply with the
requirements of Rule 16b-3 with respect to shareholder approval.

         3. TYPES OF OPTIONS AND SHARES.  Options  granted  under this Plan (the
"Options") may be either (a) incentive stock options ("ISOs") within the meaning
of  Section  422 of the  Internal  Revenue  Code of 1986  (the  "Code"),  or (b)
nonqualified  stock options  ("NQSOs"),  as designated at the time of grant. The
shares of stock that may be purchased  upon  exercise of Options  granted  under
this Plan (the "Shares") are shares of the common stock of the Company.

         4. NUMBER OF SHARES.  The  maximum  number of Shares that may be issued
pursuant to Options granted under this Plan is Seven Million (7,000,000) Shares,
subject to adjustment as provided in this Plan. If any Option is terminated  for
any reason  without  being  exercised  in whole or in part,  the Shares  thereby
released  from such Option shall be available  for purchase  under other Options
subsequently granted under this Plan. At all times during the term of this Plan,
the Company shall reserve and keep  available  such number of Shares as shall be
required to satisfy the requirements of outstanding Options under this Plan.

         5.  ADMINISTRATION.  This  Plan may be  administered  by the Board or a
Committee appointed by the Board (the "Committee").  If, at the time the Company
registers  under the Exchange  Act, a majority of the Board is not  comprised of
Disinterested  Persons,  the Board shall  appoint a Committee  consisting of not
less than three persons (who need not be members of the Board),  each of whom is
a  "Disinterested  Person" (as  defined in Section  6(b)(iv) of the Plan) and an
"Outside  Director"  (as defined in Section  6(b)(vi) of the Plan) or  qualifies
under transition rules as an Outside Director.  As used in this Plan, references
to the "Committee" shall mean either such Committee or the Board if no Committee
has been established.  After registration of the Company under the Exchange Act,
Board  members  who are not  Disinterested  Persons  may not vote on any matters
affecting  the  administration  of this  Plan  or on the  grant  of any  Options
pursuant to this Plan to any officer or director of the Company or other  person
(in each case, an "Insider")  whose  transactions in the Company's  common stock
are subject to Section  16(b) of the  Exchange  Act,  but any such member may be
counted for  determining  the  existence of a quorum at any meeting of the Board
during which action is taken with respect to Options or  administration  of this
Plan and may vote on the grant of any  Options  pursuant to this Plan other than
to Insiders.  The  interpretation  by the Committee of any of the  provisions of
this Plan or any Option  granted under this Plan shall be final and binding upon
the  Company  and all  persons  having an  interest  in any Option or any Shares
purchased  pursuant to an Option.  The  Committee  may delegate the authority to
officers of the Company to grant  Options  under this Plan to Optionees  who are
not Insiders of the Company.  No Optionee shall be eligible to receive more than
500,000 Shares at any time during the term of this Plan pursuant to the grant of
Options hereunder.

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         6.  ELIGIBILITY.  Options  may  be  granted  only  to  such  employees,
officers,  directors and consultants of the Company or any Parent, Subsidiary or
Affiliate of the Company (as defined  below) as the Committee  shall select from
time to time in its sole discretion ("Optionees"),  provided that only employees
of the Company or a Parent or  Subsidiary  of the  Company  shall be eligible to
receive ISOs. An Optionee may be granted more than one Option under this Plan.

                  (a) Assumption of Options. The Company may, from time to time,
assume  outstanding  options granted by another  company,  whether in connection
with an acquisition  of such other company or otherwise,  by either (i) granting
an option under this Plan in  replacement  of the option assumed by the Company,
or (ii) treating the assumed option as if it had been granted under this Plan if
the terms of such  assumed  option could be applied to an option  granted  under
this Plan.  Such  assumption  shall be  permissible if the holder of the assumed
option would have been  eligible to be granted an option  hereunder if the other
Company had applied the rules of this Plan to such grant.

                  (b)  Definitions.  As used in the Plan,  the  following  terms
shall have the following meanings:

                           (i) "Parent"  means any  corporation  (other than the
Company) in an unbroken chain of corporations ending with the Company if, at the
time of the  granting of the Option,  each of such  corporations  other than the
Company owns stock  possessing 50% or more of the total combined voting power of
all classes of stock in one of the other corporations in such chain.

                           (ii) "Subsidiary"  means any corporation  (other than
the Company) in an unbroken chain of corporations beginning with the Company if,
at the time of granting of the Option,  each of the corporations  other than the
last  corporation in the unbroken chain owns stock possessing 50% or more of the
total  combined  voting  power  of all  classes  of  stock  in one of the  other
corporations in such chain.

                           (iii)   "Affiliate"   means  any   corporation   that
directly,  or  indirectly  through  one or more  intermediaries,  controls or is
controlled  by, or is under  common  control  with  another  corporation,  where
"control"  (including the terms "controlled by" and "under common control with")
means the possession, direct or indirect, of the power to cause the direction of
the management and policies of the corporation, whether through the ownership of
voting securities, by contract or otherwise.

                           (iv)  "Disinterested  Person"  shall have the meaning
set forth in Rule  16b-3(d)(3)  as  promulgated  by the  Securities and Exchange
Commission  ("SEC")  under  Section  16(b) of the Exchange  Act, as such rule is
amended from time to time and as interpreted by the SEC.

                           (v) "Fair  Market  Value"  shall mean the fair market
value of the Shares as  determined  by the  Committee  from time to time in good
faith. If a public market exists for the Shares,  the Fair Market Value shall be
the average of the last  reported  bid and asked  prices for Common Stock of the
Company on the last  trading day prior to the date of  determination  or, in the
event the  Common  Stock of the  Company  is listed on a stock  exchange  or the
Nasdaq National Market, the Fair Market Value shall be the closing price on such
exchange  or  quotation  system  on the last  trading  day  prior to the date of
determination.

                           (vi) "Outside  Director"  shall mean any director who
is not (i) a current  employee  of the  Company  or any  Parent,  Subsidiary  or
Affiliate of the Company,  (ii) a former  employee of the Company or any Parent,
Subsidiary or Affiliate of the Company who is receiving  compensation  for prior
services  (other than benefits  under a  tax-qualified  pension  plan),  (iii) a
current or former officer of the Company or any Parent,  Subsidiary or Affiliate
of the Company or (iv) currently receiving compensation for personal services in
any  capacity,  other  than as a  director,  from  the  Company  or any  Parent,
Subsidiary or Affiliate of the Company; provided,  however, that at such time as
the term "Outside  Director",  as used in Section 162(m) of the Code, is 

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defined in the regulations  promulgated under Section 162(m), "Outside Director"
shall have the meaning set forth in such  regulations,  as amended  from time to
time and as interpreted by the Internal Revenue Service.

         7. TERMS AND  CONDITIONS  OF OPTIONS.  The  Committee  shall  determine
whether  each Option is to be an ISO or an NQSO,  the number of Shares for which
the Option  shall be granted,  the  exercise  price of the  Option,  the periods
during which the Option may be exercised,  and all other terms and conditions of
the Option, subject to the following terms and conditions:

                  (a) Form of Option Grant.  Each Option granted under this Plan
shall be evidenced by a written Stock Option Grant ("Grant") in such form (which
need not be the same for each Optionee) as the Committee shall from time to time
approve,  which  Grant  shall  comply  with  and be  subject  to the  terms  and
conditions of this Plan.

                  (b) Exercise  Price.  The exercise price of an Option shall be
not less than the Fair Market  Value of the Shares,  at the time that the Option
is granted.  The exercise  price of any Option granted to a person owning 10% or
more of the total  combined  voting power of all classes of stock of the Company
or any Parent or Subsidiary of the Company ("Ten Percent Shareholder") shall not
be less  than  110% of the Fair  Market  Value of the  Shares at the time of the
grant, as determined by the Committee in good faith.

                  (c) Exercise Period.  Options shall be exercisable  within the
times or upon the events  determined by the Committee as set forth in the option
grant;  provided,  however,  that no  Option  shall  be  exercisable  after  the
expiration  of ten years  from the date the  option  is  granted,  and  provided
further that no Option granted to a Ten Percent Shareholder shall be exercisable
after the expiration of five years from the date the Option is granted.

                  (d)  Limitations  on ISOs.  The  aggregate  Fair Market  Value
(determined  as of the time an Option is granted) of stock with respect to which
ISOs are  exercisable for the first time by an Optionee during the calendar year
(under this Plan or under any other  incentive  stock option plan of the Company
or any Parent or Subsidiary of the Company)  shall not exceed  $100,000.  If the
Fair  Market  Value of stock  with  respect  to which  ISOs are first  exercised
exceeds  $100,000,  the Options for the first  $100,000  worth of stock shall be
ISOs and options for the amount in excess of $100,000 shall be NQSOs.

                  (e) Date of Grant. The date of grant of an Option shall be the
date on which the Committee makes the  determination to grant such Option unless
otherwise specified by the Committee. The Grant representing the Option shall be
delivered  to the Optionee  within a  reasonable  time after the granting of the
Option.

                  (f)  Assumed  Options.  In the event the  Company  assumes  an
option granted by another company, the terms and conditions of such option shall
remain unchanged  (except the exercise price and the number and nature of shares
issuable upon exercise, which will be adjusted appropriately pursuant to Section
425(c)  of the  Code).  In the event the  Company  elects to grant a new  option
rather than assuming an existing  option (as specified in Section 6(a), such new
option  need not be  granted at Fair  Market  Value on the date of grant and may
instead be granted with a similarly adjusted exercise price.

         8.       EXERCISE OF OPTIONS.

                  (a) Notice.  Options may be exercised  only by delivery to the
Company of a written  notice and exercise  agreement  in a form  approved by the
Committee,  stating  the  number of Shares  being  purchased,  the  restrictions
imposed on the Shares and such  representations  and  agreements  regarding  the
Optionee's investment intent and access to information as may be required by the
Company to comply with applicable  securities laws together with payment in full
of the exercise price for the number of Shares being purchased.

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                  (b)  Payment.  Payment  for the Shares may be made (i) in cash
(by check); (ii) by surrender of shares of common stock of the Company that have
been owned by  Optionee  for more than six (6) months  (and which have been paid
for within the meaning of SEC Rule 144 and, if such shares were  purchased  from
the  Company  by use of a  promissory  note,  such note has been fully paid with
respect to such  shares) or were  obtained  by the  Optionee  in the open public
market,  having a Fair Market Value equal to the  exercise  price of the Option;
(iii) where  permitted by  applicable  law and approved by the  Committee in its
sole discretion,  by tender of a full recourse promissory note having such terms
as may be approved by the Committee;  (iv) provided that a public market for the
Company's stock exists,  through a "same day sale"  commitment from the Optionee
and a broker-dealer  that is a member of the National  Association of Securities
Dealers (a "NASD Dealer")  whereby the Optionee  irrevocably  elects to exercise
the  Option  and to sell a portion  of the  Shares so  purchased  to pay for the
exercise price and whereby the NASD Dealer  irrevocably  commits upon receipt of
such Shares to forward the exercise price directly to the Company; or (v) by any
combination  of the  foregoing  where  approved  by the  Committee  in its  sole
discretion.  Optionees  who are not  employees or directors of the Company shall
not be  entitled to purchase  Shares with a  promissory  note unless the note is
adequately secured by collateral other than the Shares.

                  (c)  Withholding  Taxes.  Prior to issuance of the Shares upon
exercise of an Option, the Optionee shall pay or make adequate provision for any
federal or state withholding obligations of the Company, if applicable.

                  (d)  Limitations  on  Exercise.  Notwithstanding  the exercise
periods set forth in the Grant, exercise of an Option shall always be subject to
the following limitations:

                           (i)  If an  Optionee  ceases  to be  employed  by the
Company or any Parent,  Subsidiary  or  Affiliate  of the Company for any reason
except death or disability, the Optionee may exercise such Optionee's Options to
the extent (and only to the extent) that it would have been exercisable upon the
date of  termination,  within three (3) months after the date of termination (or
such shorter time period as may be specified in the Grant),  provided  that,  if
Optionee  is an Insider  and the  Company  is  subject  to Section  16(b) of the
Exchange Act, the  Optionee's  Option will be  exercisable  for a period of time
sufficient to allow such Optionee from having a matching purchase and sale under
Section 16(b),  with any extension  beyond three (3) months from  termination of
employment in the case of an Option constituting an ISO being deemed to be as an
NQSO, and provided  further that in no event may an Option be exercisable  later
than the expiration date of the Option.

                           (ii) If an Optionee's  employment with the Company or
any Parent,  Subsidiary or Affiliate of the Company is terminated because of the
death of the Optionee or  disability  of Optionee  within the meaning of Section
22(e)(3) of the Code,  such  Optionee's  Options may be  exercised to the extent
(and only to the extent) that it would have been  exercisable by the Optionee on
the  date  of   termination,   by  the   Optionee  (or  the   Optionee's   legal
representative) within twelve (12) months after the date of termination (or such
shorter time period as may be specified in the Grant), but in any event no later
than the expiration date of the Options.

                           (iii)  The   Committee   shall  have   discretion  to
determine  whether the  Optionee has ceased to be employed by the Company or any
Parent,  Subsidiary or Affiliate of the Company and the effective  date on which
such employment terminated.

                           (iv) In the case of an  Optionee  who is a  director,
independent  consultant,  contractor  or advisor,  the  Committee  will have the
discretion to determine  whether the Optionee is "employed by the Company or any
Parent,  Subsidiary  or  Affiliate  of the  Company"  pursuant to the  foregoing
Sections.

                           (v) An Option  shall not be  exercisable  unless such
exercise is in compliance  with the Securities Act of 1933, as amended,  and all
applicable state securities laws, as they are in effect on the date of exercise.

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                           (vi) The Committee  may specify a reasonable  minimum
number of Shares that may be purchased  on any  exercise of an Option,  provided
that such minimum number will not prevent the Optionee from  exercising the full
number of Shares as to which the Option is then exercisable.

         9.  NONTRANSFERABILITY OF OPTIONS. During the lifetime of the Optionee,
an Option  shall be  exercisable  only by the  Optionee.  No Option may be sold,
pledged, assigned, hypothecated,  transferred or disposed of in any manner other
than by will or by the laws of descent and distribution.

         10.  PRIVILEGES OF STOCK  OWNERSHIP.  No Optionee shall have any of the
rights of a  shareholder  with respect to any Shares  subject to an Option until
the Option has been validly exercised. No adjustment shall be made for dividends
or  distributions or other rights for which the record date is prior to the date
of exercise,  except as provided in this Plan. The Company shall provide to each
Optionee a copy of the annual financial  statements of the Company, at such time
after the close of each fiscal  year of the Company as they are  released by the
Company to its shareholders.

         11.  ADJUSTMENT  OF  OPTIONS  SHARES.  In the event  that the number of
outstanding  shares  of  common  stock  of the  Company  is  changed  by a stock
dividend,  stock split,  reverse stock split,  combination,  reclassification or
similar change in the capital  structure of the Company  without  consideration,
the number of Shares  available under this Plan and the number of Shares subject
to outstanding Options and the exercise price per share of such Options shall be
proportionately  adjusted,  subject  to any  required  action  by the  Board  or
shareholders of the Company and compliance with applicable securities; provided,
however,  that no certificate or scrip  representing  fractional shares shall be
issued upon exercise of any Option and any resulting  fractions of a Share shall
be ignored.

         12. NO OBLIGATION TO EMPLOY. Nothing in this Plan or any Option granted
under this Plan shall confer on any Optionee any right to continue in the employ
of the Company or any Parent, Subsidiary or Affiliate of the Company or limit in
any way the right of the Company or any Parent,  Subsidiary  or Affiliate of the
Company to terminate  the  Optionee's  employment  at any time,  with or without
cause.

         13.  COMPLIANCE  WITH LAWS.  The grant of Options  and the  issuance of
Shares upon  exercise of any Options  shall be subject to and  conditioned  upon
compliance with all applicable requirements of law, including without limitation
compliance with the Securities Act of 1933, as amended, any required approval by
the Commissioner of Corporations of the State of California, compliance with all
other  applicable  state securities laws and compliance with the requirements of
any stock exchange on which the Shares may be listed. The Company shall be under
no obligation to register the Shares with the SEC or to effect  compliance  with
the registration or  qualification  requirements of any state securities laws or
stock exchange.

         14.  RESTRICTIONS  ON SHARES.  At the discretion of the Committee,  the
Company  may  reserve to itself or its  assignee(s)  in the Grant (a) a right of
first  refusal  to  purchase  any  Shares  that  an  Optionee  (or a  subsequent
transferee)  may  propose  to  transfer  to a third  party  and  (b) a right  to
repurchase  all Shares held by an Optionee upon the  Optionee's  termination  of
employment or service with the Company or its Parent, Subsidiary or Affiliate of
the  Company  for any  reason  within  a  specified  time as  determined  by the
Committee at the time of grant at (i) the  Optionee's  original  purchase  price
(provided  that the right to repurchase at such price shall lapse at the rate of
at least 20% per year from the date of  grant),  (ii) the Fair  Market  Value of
such  Shares  as  determined  by the  Committee  in good  faith or (iii) a price
determined by a formula or other provision set forth in the Grant.

         15. ASSUMPTION OF OPTIONS BY SUCCESSORS.  In the event of a dissolution
or  liquidation  of the  Company,  a merger  in  which  the  Company  is not the
surviving  corporation,  or the sale of  substantially  all of the assets of the
Company,  any or all  outstanding  Options shall,  notwithstanding  any contrary
terms of the Grant,  accelerate and become exercisable in full at least ten days
prior  to  (and  shall  expire  on)  the   consummation  of  such   dissolution,
liquidation, merger or sale of stock or sale of assets on such conditions as the
Committee  shall  determine  unless  the  successor   corporation   assumes  the
outstanding  Options  or  substitutes 

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substantially equivalent options. The aggregate Fair Market Value (determined at
the time an Option is granted) of stock with  respect to ISOs which first become
exercisable in the year of such dissolution,  liquidation, merger, sale of stock
or sale of assets cannot exceed $100,000.  Any remaining  accelerated ISOs shall
be NQSOs.

         16.  AMENDMENT OR  TERMINATION  OF PLAN.  The Committee may at any time
terminate or amend this Plan in any respect (including,  but not limited to, any
form of Grant,  agreement or instrument  to be executed  pursuant to this Plan);
provided,  however,  that the Committee  shall not,  without the approval of the
holders of a majority of the  outstanding  voting  shares of the Company,  amend
this Plan in any manner that requires such shareholder  approval pursuant to the
Code or the  regulations  promulgated  thereunder  as such  provisions  apply to
incentive  stock  option plans or pursuant to the Exchange Act or Rule 16b-3 (or
its successor) promulgated thereunder.

         17.  TERM OF PLAN.  Options  may be granted  pursuant to this Plan from
time to time  within a period of ten years from the date this Plan is adopted by
the Board.


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