<PAGE>   1
                                  EXHIBIT 4.1

                          OBERON SOFTWARE INCORPORATED
                             1990 STOCK OPTION PLAN

                                DECEMBER 27, 1990

                      (AS AMENDED THROUGH AUGUST 20, 1998)



     1. Purpose. The purpose of the Oberon Software Incorporated 1990 Stock
Option Plan (the "Plan") is to further the growth and development of Oberon
Software Incorporated ("OSI") and any subsidiary and parent corporations, as
hereinafter defined (OSI and such subsidiary and parent corporations are
collectively herein referred to, unless the context otherwise requires, as the
"Company"), by granting to those employees of the Company and the other persons
rendering services to the Company referred to in Section 6, as an incentive and
encouragement to stock ownership, options ("Options") to purchase shares of the
Company's common stock, par value $.01 per share ("Common Stock"), and thereby
obtain a proprietary interest in the enterprise and a more direct stake in its
continuing welfare.

     2. Administration. The Plan shall be administered by the Board of Directors
of OSI (the "Board").

     3. Grant of Options. Options shall be granted on behalf of OSI by the
Board; provided, however, that no Options under the Plan may be granted after
December 27, 2000. The Board shall, from time to time within the limits of the
Plan, determine the persons to whom Options are to be granted, the number of
shares to be optioned, the option price, the manner in which such option price
shall be payable, and the time or times during the Exercise Period (as defined
in Section 8) at which each such Option shall become exercisable. Options
granted under the Plan may be either incentive stock options, within the meaning
of Section 422A of the Internal Revenue Code of 1986 (the "Code"), or
non-statutory stock options. Each Option granted under the Plan shall be
designated by the Board at the time the Option is granted as either an incentive
stock option or a non-statutory stock option.

     4. Definitions. As used herein, the terms "subsidiary corporation" and
"parent corporation" shall mean a "subsidiary corporation" and a "parent
corporation" as such terms are defined in Section 425 of the Code. As used
herein, the term "10% shareholder" shall mean an employee who, at the time an
option is granted, owns stock possessing more than 10% of the total combined
voting power of all classes of stock of OSI or any of its parent or subsidiary
corporations.

     5. Shares Subject to the Plan. An aggregate of up to 1,998,466 shares of
the Common Stock shall be available for the grant of Options under the Plan.
Such shares may be authorized and unissued shares or shares held in OSI's
treasury. All shares subject to Options that shall have terminated or shall have
been canceled for any reason shall be available for subsequent optioning under
the Plan.



<PAGE>   2
                          OBERON SOFTWARE INCORPORATED
                             1990 STOCK OPTION PLAN

                                DECEMBER 27, 1990

                      (AS AMENDED THROUGH AUGUST 20, 1998)


     6. Participants. All officers and other key employees of the Company shall
be eligible to receive incentive or non-statutory stock options and thereby
become participants in the Plan. All non-employee directors of the Company and
all non-employee consultants retained by the Company shall become eligible to
receive non-statutory stock options and thereby become participants in the Plan.
In granting Options, the Board may include or exclude previous participants in
the Plan as the Board may determine.

     7. Option Price. The price at which shares may from time to time be
optioned under the Plan shall be, in the case of incentive stock options granted
to employees other than 10% shareholders, not less than the fair market value of
such shares at the time the Option is granted, as determined in good faith by
the Board at each time that such Options are granted by it; in the case of
incentive stock options granted to 10% shareholders, such price shall be not
less than 110% of such fair market value; and in the case of non-statutory stock
options, such price shall be not less than par value.

     8. Exercise Period. Subject to the provisions of Section 15, the period for
exercising an Option (the "Exercise Period") shall be determined by the
provisions of the option agreement entered into with respect to such Option
("the Option Agreement"); provided, however, that in the case of incentive
options granted to employees other than 10% stockholders, the Exercise Period
shall in no event be longer than the ten-year period beginning with the date of
grant, and in the case of incentive stock options granted to 10% shareholders,
the Exercise Period shall in no event be longer than the five-year period
beginning with the date of grant.

     9. Payment for Shares and Related Matters. Full payment for shares
purchased, together with the amount of any tax or excise due in respect of the
sale and issue thereof, shall be paid at the time of exercise and shall be made
in cash or by check only. OSI will issue no certificates for shares until (a)
full payment therefor has been made and (b) the person purchasing such shares
provides for payment to (or withholding by) the Company of all amounts, if any,
required under then applicable provisions of the Code and state and local tax
laws to be withheld with respect to such purchase. A participant shall have none
of the rights of a stockholder until certificates for the shares purchased are
issued to him or her.

     10. Nonassignability. Each Option by its terms shall not be transferable
otherwise than by will or the laws of descent and distribution and shall be
exercisable, during a participant's lifetime, only by him or her.

                                       2
<PAGE>   3
                          OBERON SOFTWARE INCORPORATED
                             1990 STOCK OPTION PLAN

                                DECEMBER 27, 1990

                      (AS AMENDED THROUGH AUGUST 20, 1998)


     11. Conditions to Exercise of Options. The Board may, in its discretion,
require as a condition to the exercise of Options and the issuance of shares
thereunder that the participant (i) shall have represented, warranted and
agreed, in form and substance satisfactory to OSI, at the time of exercising the
Option, that he or she is acquiring the shares for his or her own account, for
investment and not with a view to or in connection with any distribution, (ii)
shall have agreed to restrictions on transfer in form and substance satisfactory
to Oberon, and (iii) shall have agreed to an endorsement which makes appropriate
reference to such representations, warranties, agreements and restrictions on
the certificate(s) representing the shares. All shares issued to participants
upon exercise of Options shall be subject to any and all restrictions on
transfer, including without limitation rights of first refusal, imposed by
applicable state or federal securities laws, by the Articles of Organization or
the By-Laws of OSI as then in effect or by the Option Agreement or any other
agreement to which the participant is a party.

     12. Conditions to Effectiveness of the Plan. No Options may be granted
under the Plan unless and until the Plan shall have been duly approved by the
stockholders of OSI.

     13. Termination or Amendment. The Board may terminate or amend the Plan any
time, and from time to time. The Board may not, however, without stockholder
approval, increase the maximum number of shares in the aggregate that may be
offered for sale under Options, or change the manner of determining the option
price or the class of employees eligible to receive incentive stock options
under the Plan; or, without the consent of the participant, alter or impair any
Option previously granted to him or her under the Plan, except as provided in
Sections 14 and 15.

     14. Effect of Changes in Common Stock. If OSI shall combine, subdivide or
reclassify the shares of Common Stock which have been or may be optioned, or
shall declare thereon any dividend payable in shares of Common Stock, or shall
take any other action of a similar nature affecting the Common Stock, then the
number and class of shares of stock as to which Options may thereafter be
granted (in the aggregate and to any participant) shall be appropriately
adjusted and, in the case of each Option outstanding at the time of any such
action, the number and class of shares which may thereafter be purchased
pursuant to such Option and the option price per share shall likewise be
appropriately adjusted, all to such extent as may be determined by the Board to
be necessary to preserve unimpaired the rights of the participant. Each and
every such determination shall be conclusive and binding upon such participant.

     15. Effect of Reorganizations. In case of any one or more
reclassifications, changes or exchanges of outstanding shares of Common Stock or
other stock (other than as provided in Section 14), or consolidations of OSI
with, or mergers of OSI into, other


                                       3
<PAGE>   4
                          OBERON SOFTWARE INCORPORATED
                             1990 STOCK OPTION PLAN

                                DECEMBER 27, 1990

                      (AS AMENDED THROUGH AUGUST 20, 1998)

corporations, or other recapitalizations or reorganizations (other than
consolidations with a subsidiary in which OSI is the continuing corporation and
which do not result in any reclassifications, changes or exchanges of shares of
OSI), or in case of any one or more sales or conveyances to another corporation
of the property of OSI as an entirety, or substantially as an entirety, any and
all of which are hereinafter in this Section called "Reorganizations", a
participant shall have the right, upon any subsequent exercise of any Option, to
acquire the same kind and amount of securities and property which such
participant would then have if such participant had exercised such Option
immediately before the first of any such Reorganizations and continued to hold
all securities and property which came to such participant as a result of that
and subsequent Reorganizations, less all securities and property surrendered or
canceled pursuant to any of same, the adjustment rights in Section 14 and this
Section being continuing and cumulative.

     Notwithstanding any provision of this Plan or any Option Agreement to the
contrary, the Board shall have the right in connection with any Reorganization,
upon not less than 30 days written notice to the participants, to terminate the
Exercise Period of all outstanding Options, and in such event all outstanding
Options may be exercised only at a time prior to or simultaneously with the
consummation of such Reorganization. In connection with such termination of the
Exercise Period, the Board may in its discretion cause some or all of such
Options to become fully exercisable notwithstanding any contrary terms of this
Plan or of the Option Agreements relating to such Options.

     In the event of the acquisition of OSI by means of the purchase of all of
its capital stock, or in the event of the liquidation of OSI, unless the Board
votes otherwise and so notifies all persons holding Options prior to such
purchase or liquidation, all outstanding Options, to the extent not already
exercisable, shall become fully exercisable at the time of such purchase or
liquidation and, notwithstanding any provision of this Plan or any Option
Agreement to the contrary, the Board may terminate the Exercise Period for such
Options upon not less than 30 days written notice to the holders of such
Options.

     16. Interpretation. The Board shall interpret the Plan and make and amend
such regulations with regard to the Plan as it may deem appropriate.


                                       4
<PAGE>   5
                                  Exhibit 4.1

                          OBERON SOFTWARE INCORPORATED

                AMENDMENT NO. 2 TO THE 1998 STOCK INCENTIVE PLAN

                               (OCTOBER 25, 1999)

1.      Purpose

        The purpose of this 1998 Stock Incentive Plan (the "Plan") of Oberon
Software Incorporated, a Massachusetts corporation (the "Company"), is to
advance the interests of the Company's stockholders by enhancing the Company's
ability to attract, retain and motivate persons who make (or are expected to
make) important contributions to the Company by providing such persons with
equity ownership opportunities and performance-based incentives and thereby
better aligning the interests of such persons with those of the Company's
stockholders. Except where the context otherwise requires, the term "Company"
shall include any present or future subsidiary corporations of Oberon Software
Incorporated as defined in Section 424(f) of the Internal Revenue Code of 1986,
as amended, and any regulations promulgated thereunder (the "Code").

2.      Eligibility

        All of the Company's employees, officers, directors, consultants and
advisors (and any individuals who have accepted an offer for employment) are
eligible to be granted options, restricted stock awards, or other stock-based
awards (each, an "Award") under the Plan. Each person who has been granted an
Award under the Plan shall be deemed a "Participant".

3.      Administration, Delegation

        (a) Administration by Board of Directors. The Plan will be administered
by the Board of Directors of the Company (the "Board"). The Board shall have
authority to grant Awards and to adopt, amend and repeal such administrative
rules, guidelines and practices relating to the Plan as it shall deem advisable.
The Board may correct any defect, supply any omission or reconcile any
inconsistency in the Plan or any Award in the manner and to the extent it shall
deem expedient to carry the Plan into effect and it shall be the sole and final
judge of such expediency. All decisions by the Board shall be made in the
Board's sole discretion and shall be final and binding on all persons having or
claiming any interest in the Plan or in any Award. No director or person acting
pursuant to the authority delegated by the Board shall be liable for any action
or determination relating to or under the Plan made in good faith.

        (b) Delegation to Executive Officers. To the extent permitted by
applicable law, the Board may delegate to one or more executive officers of the
Company the power to make Awards and exercise such other powers under the Plan
as the Board may determine, provided that the Board shall fix the maximum number
of shares subject to Awards and the maximum number of shares for any one
Participant to be made by such executive officers.

        (c) Appointment of Committees. To the extent permitted by applicable
law, the Board may delegate any or all of its powers under the Plan to one or
<PAGE>   6


more committees or subcommittees of the Board (a "Committee"). If and when the
common stock, $.01 value per share, of the Company (the "Common Stock") is
registered under the Securities Exchange Act of 1934 (the "Exchange Act"), the
Board shall appoint one such Committee of not less than two members, each member
of which shall be an "outside director" within the meaning of Section 162(m) of
the Code and a "non-employee director" as defined in Rule 16b-3 promulgated
under the Exchange Act." All references in the Plan to the "Board" shall mean
the Board or a Committee of the Board or the executive officer referred to in
Section 3(b) to the extent that the Board's powers or authority under the Plan
have been delegated to such Committee or executive officer.

4.      Stock Available for Awards

        (a) Number of Shares. Subject to adjustment under Section 8, Awards may
be made under the Plan for up to 5,102,489 shares of Common Stock plus shares
subject to options granted under the Company's 1990 Stock Option Plan as of
September 29, 1999 that expire by their terms and are not exercised, provided
that the aggregate number of shares issuable under the Plan shall not exceed
6,051,589 shares of Common Stock. If any Award expires or is terminated,
surrendered or canceled without having been fully exercised or is forfeited in
whole or in part or results in any Common Stock not being issued, the unused
Common Stock covered by such Award shall again be available for the grant of
Awards under the Plan, subject, however, in the case of Incentive Stock Options
(as hereinafter defined), to any limitation required under the Code. Shares
issued under the Plan may consist in whole or in part of authorized but unissued
shares or treasury shares.

        (b) Per-Participant Limit. Subject to adjustment under Section 8, for
Awards granted after the Common Stock is registered under the Exchange Act, the
maximum number of shares of Common Stock with respect to which an Award may be
granted to any Participant under the Plan shall be 1,000,000 per calendar year.
The per-Participant limit described in this Section 4(b) shall be construed and
applied consistently with Section 162(m) of the Code.

5.      Stock Options

        (a) General. The Board may grant options to purchase Common Stock (each,
an "Option") and determine the number of shares of Common Stock to be covered by
each Option, the exercise price of each Option and the conditions and
limitations applicable to the exercise of each Option, including conditions
relating to applicable federal or state securities laws, as it considers
necessary or advisable. An Option which is not intended to be an Incentive Stock
Option (as hereinafter defined) shall be designated a "Nonstatutory Stock
Option".

        (b) Incentive Stock Options. An Option that the Board intends to be an
"incentive stock option" as defined in Section 422 of the Code (an "Incentive
Stock Option") shall only be granted to employees of the Company and shall be
subject to and shall be construed consistently with the requirements of Section
422 of the Code. The Company shall have no liability to a Participant, or any
other party, if an Option (or any part thereof) which is intended to be an
Incentive Stock Option is not an Incentive Stock Option.

        (c) Exercise Price. The Board shall establish the exercise price at the

<PAGE>   7

time each Option is granted and specify it in the applicable option agreement,
which exercise price shall not be less than the par value per share of the
Common Stock.

        (d) Duration of Options. Each Option shall be exercisable at such times
and subject to such terms and conditions as the Board may specify in the
applicable option agreement.

        (e) Exercise of Option. Options may be exercised by delivery to the
Company of a written notice of exercise signed by the proper person or by any
other form of notice (including electronic notice) approved by the Board
together with payment in full as specified in Section 5(f) for the number of
shares for which the Option is exercised.

        (f) Payment Upon Exercise. Common Stock purchased upon the exercise of
an Option granted under the Plan shall be paid for as follows:

               (1) in cash or by check, payable to the order of the Company;

               (2) except as the Board may, in its sole discretion, otherwise
provide in an option agreement, (i) delivery of an irrevocable and unconditional
undertaking by a creditworthy broker to deliver promptly to the Company
sufficient funds to pay the exercise price or (ii) delivery by the Participant
to the Company of a copy of irrevocable and unconditional instructions to a
creditworthy broker to deliver promptly to the Company cash or a check
sufficient to pay the exercise price;

               (3) at such time as the Common Stock is registered under the
Exchange Act, delivery of shares of Common Stock owned by the Participant valued
at their fair market value as determined by (or in a manner approved by) the
Board in good faith ("Fair Market Value"), which Common Stock was owned by the
Participant at least six months prior to such delivery;

               (4) to the extent permitted by the Board, in its sole discretion
(i) by delivery of a promissory note of the Participant to the Company on terms
determined by the Board, or (ii) by payment of such other lawful consideration
as the Board may determine; or

               (5) any combination of the above permitted forms of payment.

6.      Restricted Stock

        (a) Grants. The Board may grant Awards entitling recipients to acquire
shares of Common Stock at any price equal to or greater than the par value
thereof, subject to the right of the Company to repurchase all or part of such
shares at their issue price or other stated or formula price from the recipient
in the event that conditions specified by the Board in the applicable Award are
not satisfied prior to the end of the applicable restriction period or periods
established by the Board for such Award (each, "Restricted Stock Award").

        (b) Terms and Conditions. The Board shall determine the terms and
conditions of any such Restricted Stock Award, including the conditions for
repurchase and the issue price, if any. Any stock certificates issued in respect
of a Restricted Stock Award shall be registered in the name of the Participant
and,
<PAGE>   8

unless otherwise determined by the Board, deposited by the Participant,
together with a stock power endorsed in blank, with the Company (or its
designee). At the expiration of the applicable restriction periods, the Company
(or such designee) shall deliver the certificates no longer subject to such
restrictions to the Participant or if the Participant has died, to the
beneficiary designated, in a manner determined by the Board, by a Participant to
receive amounts due or exercise rights of the Participant in the event of the
Participant's death (the "Designated Beneficiary"). In the absence of an
effective designation by a Participant, Designated Beneficiary shall mean the
Participant's estate.

7.      Other Stock-Based Awards

        The Board shall have the right to grant other Awards based upon the
Common Stock having such terms and conditions as the Board may determine,
including the grant of shares based upon certain conditions, the grant of
securities convertible into Common Stock and the grant of stock appreciation
rights.

8.      Adjustments for Changes in Common Stock and Certain Other Events

        (a) Changes in Capitalization. In the event of any stock split, reverse
stock split, stock dividend, recapitalization, combination of shares,
reclassification of shares, spin-off or other similar change in capitalization
or event, or any distribution to holders of Common Stock other than a normal
cash dividend, (i) the number and class of securities available under this Plan,
(ii) the per-Participant limit set forth in Section 4(b), (iii) the number and
class of securities and exercise price per share subject to each outstanding
Option, (iv) the repurchase price per share subject to each outstanding
Restricted Stock Award, and (v) the terms of each other outstanding Award shall
be appropriately adjusted by the Company (or substituted Awards may be made, if
applicable) to the extent the Board shall determine, in good faith, that such an
adjustment (or substitution) is necessary and appropriate. If this Section 8(a)
applies and Section 8(c) also applies to any event, Section 8(c) shall be
applicable to such event, and this Section 8(a) shall not be applicable.

        (b) Liquidation or Dissolution. In the event of a proposed liquidation
or dissolution of the Company, the Board shall upon written notice to the
Participants provide that all then unexercised Options will (i) become
exercisable in full as of a specified time at least 10 business days prior to
the effective date of such liquidation or dissolution and (ii) terminate
effective upon such liquidation or dissolution, except to the extent exercised
before such effective date. The Board may specify the effect of a liquidation or
dissolution on any Restricted Stock Award or other Award granted under the Plan
at the time of the grant of such Award.

        (c)    Acquisition and Change in Control Events

               (1)    Definitions

                      (a)    An "Acquisition Event" shall mean:

                             (i)    any merger or consolidation of the Company
                                    with or into another entity as a result of
                                    which the Common Stock is converted into or

<PAGE>   9

                                    exchanged for the right to receive cash,
                                    securities or other property; or

                            (ii)    any exchange of shares of the Company for
                                    cash, securities or other property pursuant
                                    to a statutory share exchange transaction.

                      (b)   A "Change in Control Event" shall mean:

                            (i)     the acquisition by an individual, entity or
                                    group (within the meaning of Section
                                    13(d)(3) or 14(d)(2) of the Securities
                                    Exchange Act of 1934, as amended (the
                                    "Exchange Act")) (a "Person") of beneficial
                                    ownership of any capital stock of the
                                    Company if, after such acquisition, such
                                    Person beneficially owns (within the meaning
                                    of Rule 13d-3 promulgated under the Exchange
                                    Act) 35% or more of either (x) the
                                    then-outstanding shares of common stock of
                                    the Company (the "Outstanding Company Common
                                    Stock") or (y) the combined voting power of
                                    the then-outstanding securities of the
                                    Company entitled to vote generally in the
                                    election of directors (the "Outstanding
                                    Company Voting Securities"); provided,
                                    however, that for purposes of this
                                    subsection (i), the following acquisitions
                                    shall not constitute a Change in Control
                                    Event: (A) any acquisition directly from the
                                    Company (excluding an acquisition pursuant
                                    to the exercise, conversion or exchange of
                                    any security exercisable for, convertible
                                    into or exchangeable for common stock or
                                    voting securities of the Company, unless the
                                    Person exercising, converting or exchanging
                                    such security acquired such security
                                    directly from the Company or an underwriter
                                    or agent of the Company), (B) any
                                    acquisition by any employee benefit plan (or
                                    related trust) sponsored or maintained by
                                    the Company or any corporation controlled by
                                    the Company, or (C) any acquisition by any
                                    corporation pursuant to a Business
                                    Combination (as defined below) which
                                    complies with clauses (x) and (y) of
                                    subsection (iii) of this definition; or

                            (ii)    such time as the Continuing Directors (as
                                    defined below) do not constitute a majority
                                    of the Board (or, if applicable, the Board
                                    of Directors of a successor corporation to
                                    the Company), where the term "Continuing
                                    Director" means at any date a member of the
                                    Board (x) who was a member of the Board on
                                    the date of the initial adoption of this
                                    Plan by
<PAGE>   10

                                    the Board or (y) who was nominated or
                                    elected subsequent to such date by at least
                                    a majority of the directors who were
                                    Continuing Directors at the time of such
                                    nomination or election or whose election to
                                    the Board was recommended or endorsed by at
                                    least a majority of the directors who were
                                    Continuing Directors at the time of such
                                    nomination or election; provided, however,
                                    that there shall be excluded from this
                                    clause (y) any individual whose initial
                                    assumption of office occurred as a result of
                                    an actual or threatened election contest
                                    with respect to the election or removal of
                                    directors or other actual or threatened
                                    solicitation of proxies or consents, by or
                                    on behalf of a person other than the Board;
                                    or

                           (iii)    the consummation of a merger, consolidation,
                                    reorganization or statutory share exchange
                                    involving the Company or a sale or other
                                    disposition of all or substantially all of
                                    the assets of the Company (a "Business
                                    Combination"), unless, immediately following
                                    such Business Combination, each of the
                                    following two conditions is satisfied: (x)
                                    all or substantially all of the individuals
                                    and entities who were the beneficial owners
                                    of the Outstanding Company Common Stock and
                                    Outstanding Company Voting Securities
                                    immediately prior to such Business
                                    Combination beneficially own, directly or
                                    indirectly, more than 50% of the
                                    then-outstanding shares of common stock and
                                    the combined voting power of the
                                    then-outstanding securities entitled to vote
                                    generally in the election of directors,
                                    respectively, of the resulting or acquiring
                                    corporation in such Business Combination
                                    (which shall include, without limitation, a
                                    corporation which as a result of such
                                    transaction owns the Company or
                                    substantially all of the Company's assets
                                    either directly or through one or more
                                    subsidiaries) (such resulting or acquiring
                                    corporation is referred to herein as the
                                    "Acquiring Corporation") in substantially
                                    the same proportions as their ownership of
                                    the Outstanding Company Common Stock and
                                    Outstanding Company Voting Securities,
                                    respectively, immediately prior to such
                                    Business Combination and (y) no Person
                                    (excluding the Acquiring Corporation or any
                                    employee benefit plan (or related trust)
                                    maintained or sponsored by the Company or by
                                    the Acquiring Corporation) beneficially
<PAGE>   11

                                    owns, directly or indirectly, 35% or more of
                                    the then-outstanding shares of common stock
                                    of the Acquiring Corporation, or of the
                                    combined voting power of the
                                    then-outstanding securities of such
                                    corporation entitled to vote generally in
                                    the election of directors (except to the
                                    extent that such ownership existed prior to
                                    the Business Combination).

                      (c)    "Good Reason" shall mean any (i) change in the
                             Participant's position with the Company which
                             materially reduces such Participant's level of
                             responsibility, (ii) reduction in the
                             Participant's level of compensation (including
                             base salary and any nondiscretionary bonuses or
                             other incentive payments earned pursuant to
                             objective standards or criteria), or (iii)
                             relocation of the place of business at which the
                             Participant is principally located to a location
                             that is greater than 50 miles from the current
                             site without the Participant's consent, from and
                             after such Change in Control Event.


                      (d)    "Cause" shall mean any (i) willful failure by the
                             Participant, which failure is not cured within 30
                             days of written notice to the Participant from the
                             Company, to perform his or her material
                             responsibilities to the Company or (ii) willful
                             misconduct by the Participant which affects the
                             business reputation of the Company.

               (2)    Effect on Options

                      (a)    Acquisition Event. Upon the occurrence of an
                             Acquisition Event (regardless of whether such
                             event also constitutes a Change in Control Event),
                             or the execution by the Company of any agreement
                             with respect to an Acquisition Event (regardless
                             of whether such event will result in a Change in
                             Control Event), the Board shall provide that all
                             outstanding Options shall be assumed, or
                             equivalent options shall be substituted, by the
                             acquiring or succeeding corporation (or an
                             affiliate thereof); provided that (i) any options
                             substituted for Incentive Stock Options shall
                             satisfy, in the determination of the Board, the
                             requirements of Section 424(a) of the Code and
                             (ii) if such Acquisition Event also constitutes a
                             Change in Control Event, except to the extent
                             specifically provided to the contrary in the
                             instrument evidencing any Option or any other
                             agreement between a Participant and the Company
                             (A) (I) with respect to all Options that become
                             exercisable ("vest") over a five-year period,
                             those shares subject to the Option which were not
                             already vested but would vest within 18

<PAGE>   12

                             months after such Change in Control Event (the "18
                             Month Accelerated Option Shares") and (II) with
                             respect to Options that vest over a four-year
                             period, those shares subject to the Option which
                             were not already vested but would vest within
                             twelve months after such Change in Control event
                             (the "12 Month Accelerated Option Shares", and
                             together with the 18 Month Accelerated Option
                             Shares, the "Accelerated Option Shares"), shall be
                             exercisable upon the occurrence of such Change in
                             Control Event and, subject to (B) below, the
                             remaining shares subject to the Option shall
                             continue to become vested in accordance with the
                             original vesting schedule set forth in such
                             Option, with that number of shares that would
                             otherwise have first become vested, multiplied by
                             a fraction (x) the numerator of which is the
                             difference between the number of shares subject to
                             the Option and the applicable Accelerated Option
                             Shares and (y) the denominator of which is the
                             number of shares subject to the Option, becoming
                             so vested on each subsequent vesting date in
                             accordance with the original schedule and (B) such
                             assumed or substituted options shall become
                             immediately exercisable in full if, on or prior to
                             the first anniversary of the date of the
                             consummation of such Acquisition Event also
                             constituting a Change in Control Event, the
                             Participant's employment with the Company or the
                             acquiring or succeeding corporation is terminated
                             for Good Reason by the Participant or is
                             terminated without Cause by the Company or the
                             acquiring or succeeding corporation.

                                    Notwithstanding the foregoing, if the
                             acquiring or succeeding corporation (or an
                             affiliate thereof) does not agree to assume, or
                             substitute for, such Options, then the Board shall
                             (x) upon written notice to the Participants,
                             provide that all then unexercised Options will
                             become exercisable in full as of a specified time
                             (the "Acceleration Time") prior to the Acquisition
                             Event and will terminate immediately prior to the
                             consummation of such Acquisition Event, except to
                             the extent exercised by the Participants before the
                             consummation of such Acquisition Event, and/or (y)
                             in the event of an Acquisition Event under the
                             terms of which holders of Common Stock will receive
                             upon consummation thereof a cash payment for each
                             share of Common Stock surrendered pursuant to such
                             Acquisition Event (the "Acquisition Price"),
                             provide that all outstanding Options shall
                             terminate upon consummation of such Acquisition
                             Event and each Participant shall receive, in
                             exchange therefor, a cash payment equal to the
                             amount (if any) by which (A) the Acquisition Price
                             multiplied by the number of shares of Common Stock
                             subject to such

<PAGE>   13

                              outstanding Options (whether or not then
                              exercisable), exceeds (B) the aggregate exercise
                              price of such Options.

                    (b)       Change in Control Event that is not an Acquisition
                              Event. Upon the occurrence of a Change in Control
                              Event that does not also constitute an Acquisition
                              Event, except to the extent specifically provided
                              to the contrary in the instrument evidencing any
                              Option or any other agreement between a
                              Participant and the Company, the vesting schedule
                              of such Option shall be accelerated in part so
                              that the Accelerated Option Shares shall
                              immediately become exercisable. The remaining
                              number of shares shall continue to become vested
                              in accordance with the original vesting schedule
                              set forth in such Option, with that number of
                              shares that would otherwise have first become
                              vested, multiplied by a fraction (x) the numerator
                              of which is the difference between the number of
                              shares subject to the Option and the applicable
                              Accelerated Option Shares and (y) the denominator
                              of which is the number of shares subject to the
                              Option, becoming so vested on each subsequent
                              vesting date in accordance with the original
                              schedule; provided, however, that each such Option
                              shall be immediately exercisable in full if, on or
                              prior to the first anniversary of the date of the
                              consummation of the Change in Control Event, the
                              Participant's employment with the Company or the
                              acquiring or succeeding corporation is terminated
                              for Good Reason by the Participant or is
                              terminated without Cause by the Company or the
                              acquiring or succeeding corporation.

          (3)       Effect on Restricted Stock Awards

                    (a)       Acquisition Event that is not a Change in Control
                              Event. Upon the occurrence of an Acquisition Event
                              that is not a Change in Control Event, the
                              repurchase and other rights of the Company under
                              each outstanding Restricted Stock Award shall
                              inure to the benefit of the Company's successor
                              and shall apply to the cash, securities or other
                              property which the Common Stock was converted into
                              or exchanged for pursuant to such Acquisition
                              Event in the same manner and to the same extent as
                              they applied to the Common Stock subject to such
                              Restricted Stock Award.

                    (b)       Change in Control Event. Upon the occurrence of a
                              Change in Control Event (regardless of whether
                              such event also constitutes an Acquisition Event),
                              except to the extent specifically provided to the
                              contrary in the instrument evidencing any
                              Restricted Stock Award or any other agreement
                              between a Participant

<PAGE>   14

                              and the Company, the vesting schedule of all
                              Restricted Stock Awards shall be accelerated in
                              part so that such number of shares that would
                              otherwise have first become free from conditions
                              or restrictions (A) within 18 months after the
                              date of the Change in Control Event in the case of
                              Restricted Stock Awards which are subject to a
                              five year Purchase Option (as defined in the
                              Restricted Stock Agreement) by the Company (the
                              "18-Month Accelerated Shares"), and (B) within 12
                              months after the date of the Change of Control
                              Event in the case of Restricted Stock Awards which
                              are subject to a four year Purchase Option by the
                              Company (the "12-Month Accelerated Shares,"
                              together with the 18-Month Accelerated Shares, the
                              "Accelerated Shares"), shall immediately become
                              free from conditions or restrictions. Subject to
                              the following sentence, the remaining number of
                              shares shall continue to become free from
                              conditions or restrictions in accordance with the
                              original schedule set forth in such Restricted
                              Stock Award, with that number of shares that would
                              otherwise have first become free from conditions
                              or restrictions, multiplied by a fraction (x) the
                              numerator of which is the difference between the
                              number of shares covered by such Restricted Stock
                              Award and the applicable Accelerated Shares and
                              (y) the denominator of which is the number of
                              shares covered by such Restricted Stock Award,
                              becoming free from conditions or restrictions on
                              each subsequent vesting date in accordance with
                              the original schedule. In addition, each such
                              Restricted Stock Award shall immediately become
                              free from all conditions or restrictions if, on or
                              prior to the first anniversary of the date of the
                              consummation of the Change in Control Event, the
                              Participant's employment with the Company or the
                              acquiring or succeeding corporation is terminated
                              for Good Reason by the Participant or is
                              terminated without Cause by the Company or the
                              acquiring or succeeding corporation.

          (4)       Effect on Other Awards

                    (a)       Acquisition Event that is not a Change in Control
                              Event. The Board shall specify the effect of an
                              Acquisition Event that is not a Change in Control
                              Event on any other Award granted under the Plan at
                              the time of the grant of such Award.

                    (b)       Change in Control Event. Upon the occurrence of a
                              Change in Control Event (regardless of whether
                              such event also constitutes an Acquisition Event),
                              except to the extent specifically provided to the
                              contrary in the instrument evidencing any Award or
                              any other agreement between a Participant and the
                              Company,

<PAGE>   15

                              the vesting schedule of all other Awards shall be
                              accelerated in part so that such number of shares
                              that would otherwise have first become
                              exercisable, realizable, vested or free from
                              conditions or restrictions (A) within 18 months
                              after the date of the Change in Control Event in
                              the case of other Awards which are subject to a
                              five year purchase option by the Company (the
                              "18-Month Accelerated Award Shares"), and (B)
                              within 12 months after the date of the Change of
                              Control Event in the case of other Awards which
                              are subject to a four year purchase option by the
                              Company (the "12-Month Accelerated Award Shares,"
                              together with the 18-Month Accelerated Award
                              Shares, the "Accelerated Award Shares"), shall
                              immediately become exercisable, realizable, vested
                              or free from conditions or restrictions. Subject
                              to the following sentence, the remaining number of
                              shares shall continue to become exercisable,
                              realizable, vested or free from conditions or
                              restrictions in accordance with the original
                              schedule set forth in such Award, with that number
                              of shares that would otherwise have first become
                              exercisable, realizable, vested or free from
                              conditions or restrictions, multiplied by a
                              fraction (x) the numerator of which is the
                              difference between the number of shares covered by
                              such Award and the applicable Accelerated Award
                              Shares and (y) the denominator of which is the
                              number of shares covered by such Award, becoming
                              so exercisable, realizable, vested or free from
                              conditions or restrictions on each subsequent
                              vesting date in accordance with the original
                              schedule. In addition, each such Award shall
                              immediately become fully exercisable, realizable,
                              vested or free from conditions or restrictions if,
                              on or prior to the first anniversary of the date
                              of the consummation of the Change in Control
                              Event, the Participant's employment with the
                              Company or the acquiring or succeeding corporation
                              is terminated for Good Reason by the Participant
                              or is terminated without Cause by the Company or
                              the acquiring or succeeding corporation.

10.     General Provisions Applicable to Awards

        (a) Transferability of Awards. Except as the Board may otherwise
determine or provide in an Award, Awards shall not be sold, assigned,
transferred, pledged or otherwise encumbered by the person to whom they are
granted, either voluntarily or by operation of law, except by will or the laws
of descent and distribution, and, during the life of the Participant, shall be
exercisable only by the Participant. References to a Participant, to the extent
relevant in the context, shall include references to authorized transferees.

        (b) Documentation. Each Award shall be evidenced by a written instrument
in such form as the Board shall determine. Each Award may contain

<PAGE>   16

terms and conditions in addition to those set forth in the Plan.

        (c) Board Discretion. Except as otherwise provided by the Plan, each
Award may be made alone or in addition or in relation to any other Award. The
terms of each Award need not be identical, and the Board need not treat
Participants uniformly.

        (d) Termination of Status. The Board shall determine the effect on an
Award of the disability, death, retirement, authorized leave of absence or other
change in the employment or other status of a Participant and the extent to
which, and the period during which, the Participant, the Participant's legal
representative, conservator, guardian or Designated Beneficiary may exercise
rights under the Award.

        (e) Withholding. Each Participant shall pay to the Company, or make
provision satisfactory to the Board for payment of, any taxes required by law to
be withheld in connection with Awards to such Participant no later than the date
of the event creating the tax liability. Except as the Board may otherwise
provide in an Award, Participants may satisfy such tax obligations in whole or
in part by delivery of shares of Common Stock, including shares retained from
the Award creating the tax obligation, valued at their Fair Market Value. The
Company may, to the extent permitted by law, deduct any such tax obligations
from any payment of any kind otherwise due to a Participant.

        (f) Amendment of Award. The Board may amend, modify or terminate any
outstanding Award, including but not limited to, substituting therefor another
Award of the same or a different type, changing the date of exercise or
realization, and converting an Incentive Stock Option to a Nonstatutory Stock
Option, provided that the Participant's consent to such action shall be required
unless the Board determines that the action, taking into account any related
action, would not materially and adversely affect the Participant.

        (g) Conditions on Delivery of Stock. The Company will not be obligated
to deliver any shares of Common Stock pursuant to the Plan or to remove
restrictions from shares previously delivered under the Plan until (i) all
conditions of the Award have been met or removed to the satisfaction of the
Company, (ii) in the opinion of the Company's counsel, all other legal matters
in connection with the issuance and delivery of such shares have been satisfied,
including any applicable securities laws and any applicable stock exchange or
stock market rules and regulations, and (iii) the Participant has executed and
delivered to the Company such representations or agreements as the Company may
consider appropriate to satisfy the requirements of any applicable laws, rules
or regulations.

        (h) Acceleration. The Board may at any time provide that any Options
shall become immediately exercisable in full or in part, that any Restricted
Stock Awards shall be free of restrictions in full or in part or that any other
Awards may become exercisable in full or in part or free of some or all
restrictions or conditions, or otherwise realizable in full or in part, as the
case may be.

11.     Miscellaneous

        (a) No Right To Employment or Other Status. No person shall have any
claim or right to be granted an Award, and the grant of an Award shall not be

<PAGE>   17

construed as giving a Participant the right to continued employment or any other
relationship with the Company. The Company expressly reserves the right at any
time to dismiss or otherwise terminate its relationship with a Participant free
from any liability or claim under the Plan, except as expressly provided in the
applicable Award.

        (b) No Rights As Stockholder. Subject to the provisions of the
applicable Award, no Participant or Designated Beneficiary shall have any rights
as a stockholder with respect to any shares of Common Stock to be distributed
with respect to an Award until becoming the record holder of such shares.
Notwithstanding the foregoing, in the event the Company effects a split of the
Common Stock by means of a stock dividend and the exercise price of and the
number of shares subject to such Option are adjusted as of the date of the
distribution of the dividend (rather than as of the record date for such
dividend), then an optionee who exercises an Option between the record date and
the distribution date for such stock dividend shall be entitled to receive, on
the distribution date, the stock dividend with respect to the shares of Common
Stock acquired upon such Option exercise, notwithstanding the fact that such
shares were not outstanding as of the close of business on the record date for
such stock dividend.

        (c) Effective Date and Term of Plan. The Plan shall become effective on
the date on which it is adopted by the Board. No Awards shall be granted under
the Plan after the completion of ten years from the earlier of (i) the date on
which the Plan was adopted by the Board or (ii) the date the Plan was approved
by the Company's stockholders, but Awards previously granted may extend beyond
that date.

        (d) Amendment of Plan. The Board may amend, suspend or terminate the
Plan or any portion thereof at any time.

        (e) Governing Law. The provisions of the Plan and all Awards made
hereunder shall be governed by and interpreted in accordance with the laws of
the Commonwealth of Massachusetts, without regard to any applicable conflicts of
law.