<PAGE>


                                                                  EXHIBIT 10.7.8
                              TANTAU SOFTWARE, INC.

                                 1999 STOCK PLAN

                    STOCK OPTION AGREEMENT -- EARLY EXERCISE

         Unless otherwise defined herein, the terms defined in the 1999 Stock
Plan shall have the same defined meanings in this Stock Option Agreement (the
"Option Agreement").

I.       NOTICE OF STOCK OPTION GRANT

         Name
         Address
         Address

         You have been granted an option to purchase Common Stock of the
Company, subject to the terms and conditions of the Plan and this Option
Agreement, as follows:

Date of Grant                               -----------------------------

Vesting Commencement Date                   -----------------------------

Exercise Price per Share                    -----------------------------

Total Number of Shares Granted              -----------------------------

Total Exercise Price                        -----------------------------

Type of Option:                              X   Incentive Stock Option
                                            ---
                                                 Non-statutory Stock Option
                                            ---

Term/Expiration Date:


EXERCISE AND VESTING SCHEDULE:

         This Option shall be exercisable in whole or in part, and shall vest
according to the following vesting schedule:

         Twenty-five percent (25%) of the Shares subject to the Option shall
become exercisable on the first anniversary of the Vesting Commencement Date,
and an additional one forty-eighth (1/48th) of the total number of Shares
subject to the Option shall become exercisable on the first day of each month
thereafter, until all such shares are exercisable, subject to Optionee's
continuing to be a Service Provider on such dates.

<PAGE>



TERMINATION PERIOD:

         This Option may be exercised, to the extent it is then vested, for
three months after Optionee ceases to be a Service Provider. Upon death or
Disability of the Optionee, this Option may be exercised, to the extent it is
then vested, for one year after Optionee ceases to be Service Provider. In no
event shall this Option be exercised later than the Term/Expiration Date as
provided above.

II. AGREEMENT

     1. GRANT OF OPTION. The Administrator of the Company hereby grants to the
Optionee named in the Notice of Grant (the "Optionee"), an option (the "Option")
to purchase the number of Shares set forth in the Notice of Grant, at the
exercise price per Share set forth in the Notice of Grant (the "Exercise
Price"), and subject to the terms and conditions of the Plan, which is
incorporated herein by reference. Subject to Section 15(c) of the Plan, in the
event of a conflict between the terms and conditions of the Plan and this Option
Agreement, the terms and conditions of the Plan shall prevail.

     If designated in the Notice of Grant as an Incentive Stock Option ("ISO"),
this Option is intended to qualify as an Incentive Stock Option as defined in
Section 422 of the Code. Nevertheless, to the extent that it exceeds the
$100,000 rule of Code Section 422(d), this Option shall be treated as a
Nonstatutory Stock Option ("NSO").

     2. EXERCISE OF OPTION. This Option shall be exercisable during its term in
accordance with the provisions of Section 9 of the Plan as follows:

         (a) RIGHT TO EXERCISE.

                  (i) Subject to subsections 2(a)(ii) and 2(a)(iii) below, this
Option shall be exercisable cumulatively according to the vesting schedule set
forth in the Notice of Grant. Alternatively, at the election of the Optionee,
this Option may be exercised in whole or in part at any time as to Shares which
have not yet vested. Vested Shares shall not be subject to the Company's
repurchase right (as set forth in the Restricted Stock Purchase Agreement,
attached hereto as EXHIBIT C-1).

                  (ii) As a condition to exercising this Option for unvested
Shares, the Optionee shall execute the Restricted Stock Purchase Agreement.

                  (iii) This Option may not be exercised for a fraction of a
Share.

         (b) METHOD OF EXERCISE. This Option shall be exercisable by delivery of
an exercise notice in the form attached as EXHIBIT A (the "Exercise Notice")
which shall state the election to

                                      -2-

<PAGE>


exercise the Option, the number of Shares with respect to which the Option is
being exercised, and such other representations and agreements as may be
required by the Company. The Exercise Notice shall be accompanied by payment of
the aggregate Exercise Price as to all Exercised Shares. This Option shall be
deemed to be exercised upon receipt by the Company of such fully executed
Exercise Notice accompanied by the aggregate Exercise Price.

     No Shares shall be issued pursuant to the exercise of an Option unless such
issuance and such exercise complies with Applicable Laws. Assuming such
compliance, for income tax purposes the Shares shall be considered transferred
to the Optionee on the date on which the Option is exercised with respect to
such Shares.

     3. OPTIONEE'S REPRESENTATIONS. In the event the Shares have not been
registered under the Securities Act of 1933, as amended, at the time this Option
is exercised, the Optionee shall, if required by the Company, concurrently with
the exercise of all or any portion of this Option, deliver to the Company his or
her Investment Representation Statement in the form attached hereto as EXHIBIT
B.

     4. LOCK-UP PERIOD. Optionee hereby agrees that, if so requested by the
Company or any representative of the underwriters (the "Managing Underwriter")
in connection with any registration of the offering of any securities of the
Company under the Securities Act, Optionee shall not sell or otherwise transfer
any Shares or other securities of the Company during the 180-day period (or such
other period as may be requested in writing by the Managing Underwriter and
agreed to in writing by the Company) (the "Market Standoff Period") following
the effective date of a registration statement of the Company filed under the
Securities Act. Such restriction shall apply only to the first registration
statement of the Company to become effective under the Securities Act that
includes securities to be sold on behalf of the Company to the public in an
underwritten public offering under the Securities Act. The Company may impose
stop-transfer instructions with respect to securities subject to the foregoing
restrictions until the end of such Market Standoff Period.

     5. METHOD OF PAYMENT. Payment of the aggregate Exercise Price shall be by
any of the following, or a combination thereof, at the election of the Optionee:

          (a) cash or check;

          (b) consideration received by the Company under a formal cashless
exercise program adopted by the Company in connection with the Plan; or

          (c) surrender of other Shares which, (i) in the case of Shares
acquired upon exercise of an option, have been owned by the Optionee for more
than six (6) months on the date of surrender, and (ii) have a Fair Market Value
on the date of surrender equal to the aggregate Exercise Price of the Exercised
Shares.

     6. RESTRICTIONS ON EXERCISE. This Option may not be exercised until such
time as the Plan has been approved by the shareholders of the Company, or if the
issuance of such Shares upon such

                                      -3-


<PAGE>

exercise or the method of payment of consideration for such shares would
constitute a violation of any Applicable Law.

     7. NON-TRANSFERABILITY OF OPTION. This Option may not be transferred in any
manner otherwise than by will or by the laws of descent or distribution and may
be exercised during the lifetime of Optionee only by Optionee. The terms of the
Plan and this Option Agreement shall be binding upon the executors,
administrators, heirs, successors and assigns of the Optionee.


     8. TERM OF OPTION. This Option may be exercised only within the term
set out in the Notice of Grant, and may be exercised during such term only in
accordance with the Plan and the terms of this Option.

     9. TAX CONSEQUENCES. Set forth below is a brief summary as of the date
of this Option of some of the federal tax consequences of exercise of this
Option and disposition of the Shares. THIS SUMMARY IS NECESSARILY INCOMPLETE,
AND THE TAX LAWS AND REGULATIONS ARE SUBJECT TO CHANGE. THE OPTIONEE SHOULD
CONSULT A TAX ADVISER BEFORE EXERCISING THIS OPTION OR DISPOSING OF THE SHARES.

          (a) EXERCISE OF NSO. There may be a regular federal income tax
liability upon the exercise of an NSO. The Optionee will be treated as having
received compensation income (taxable at ordinary income tax rates) equal to the
excess, if any, of the Fair Market Value of the Exercised Shares on the date of
exercise over the Exercise Price. If Optionee is an Employee or a former
Employee, the Company will be required to withhold from Optionee's compensation
or collect from Optionee and pay to the applicable taxing authorities an amount
in cash equal to a percentage of this compensation income at the time of
exercise, and may refuse to honor the exercise and refuse to deliver Shares if
such withholding amounts are not delivered at the time of exercise.

          (b) EXERCISE OF ISO. If this Option qualifies as an ISO, there will be
no regular federal income tax liability upon the exercise of the Option,
although the excess, if any, of the Fair Market Value of the Exercised Shares on
the date of exercise over the Exercise Price will be treated as an adjustment to
the alternative minimum tax for federal tax purposes and may subject the
Optionee to the alternative minimum tax in the year of exercise.

          (c) EXERCISE OF ISO FOLLOWING DISABILITY. If the Optionee ceases to be
an Employee as a result of a disability that is not a total and permanent
disability as defined in Section 22(e)(3) of the Code, to the extent permitted
on the date of termination, the Optionee must exercise an ISO within three
months of such termination for the ISO to be qualified as an ISO.

          (d) DISPOSITION OF SHARES. In the case of an NSO, if Shares are held
for at least one year, any gain realized on disposition of the Shares will be
treated as long-term capital gain for federal income tax purposes. In the case
of an ISO, if Shares transferred pursuant to the Option are held for at least
one year after exercise and at least two years after the Date of Grant, any gain
realized on disposition of the Shares will also be treated as long-term capital
gain for federal income tax purposes. If Shares purchased under an ISO are
disposed of within one year after exercise or two years after the Date of Grant,
any gain realized on such disposition will be treated as compensation


                                      -4-

<PAGE>


income (taxable at ordinary income rates) to the extent of the difference
between the Exercise Price of the Exercised Shares and the lesser of (i) the
Fair Market Value of the Exercised Shares on the date of exercise, or (ii) the
sale price of the Exercised Shares. Different rules may apply if the Shares are
subject to a substantial risk of forfeiture (within the meaning of Section 83 of
the Code) at the time of purchase. Any additional gain will be taxed as capital
gain, short-term depending on the period that the ISO Shares were held.

          (e) NOTICE OF DISQUALIFYING DISPOSITION OF ISO SHARES. If the Option
granted to Optionee herein is an ISO, and if Optionee sells or otherwise
disposes of any of the Shares acquired pursuant to the ISO on or before the
later of (i) the date two years after the Date of Grant, or (ii) the date one
year after the date of exercise, the Optionee shall immediately notify the
Company in writing of such disposition. Optionee agrees that Optionee may be
subject to income tax withholding by the Company on the compensation income
recognized by the Optionee.

          (f) SECTION 83(b) ELECTION FOR UNVESTED SHARES PURCHASED PURSUANT TO
OPTIONS. With respect to the exercise of an Option for unvested Shares, an
election (the "Election") may be filed by the Optionee with the Internal Revenue
Service, WITHIN 30 DAYS of the purchase of the Shares, electing pursuant to
Section 83(b) of the Code to be taxed currently on any difference between the
purchase price of the Shares and their Fair Market Value on the date of
purchase. In the case of an NSO, this will result in a recognition of taxable
income to the Optionee on the date of exercise, measured by the excess, if any,
of the Fair Market Value of the Exercised Shares, at the time the Option is
exercised over the purchase price for the Exercised Shares. Absent such an
election, taxable income will be measured and recognized by Optionee at the time
or times on which the Company's Repurchase Option lapses. In the case of an ISO,
such an election will result in a recognition of income to the Optionee for
alternative minimum tax purposes on the date of exercise, measured by the
excess, if any, of the Fair Market Value of the Exercised Shares, at the time
the Option is exercised, over the purchase price for the Exercised Shares.
Absent such an election, alternative minimum taxable income will be measured and
recognized by Optionee at the time or times on which the Company's Repurchase
Option lapses. Optionee is strongly encouraged to seek the advice of his or her
own tax consultants in connection with the purchase of the Shares and the
advisability of filing of the Election under Section 83(b) of the Code. A form
of Election under Section 83(b) is attached hereto as EXHIBIT C-5 for reference.

     OPTIONEE ACKNOWLEDGES THAT IT IS OPTIONEE'S SOLE RESPONSIBILITY AND NOT THE
COMPANY'S TO FILE TIMELY THE ELECTION UNDER SECTION 83(b), EVEN IF OPTIONEE
REQUESTS THE COMPANY OR ITS REPRESENTATIVE TO MAKE THIS FILING ON OPTIONEE'S
BEHALF.

     10. ENTIRE AGREEMENT; GOVERNING LAW. The Plan is incorporated herein by
reference. The Plan and this Option Agreement constitute the entire agreement of
the parties with respect to the subject matter hereof and supersede in their
entirety all prior undertakings and agreements of the Company and Optionee with
respect to the subject matter hereof, and may not be modified adversely to the
Optionee's interest except by means of a writing signed by the Company and
Optionee. This

                                      -5-

<PAGE>


Option Agreement is governed by the internal substantive laws but not the choice
of law rules of Texas.

     11. NO GUARANTEE OF CONTINUED SERVICE. OPTIONEE ACKNOWLEDGES AND AGREES
THAT THE VESTING OF SHARES PURSUANT TO THE VESTING SCHEDULE HEREOF IS EARNED
ONLY BY CONTINUING AS A SERVICE PROVIDER AT THE WILL OF THE COMPANY (NOT THROUGH
THE ACT OF BEING HIRED, BEING GRANTED THIS OPTION OR ACQUIRING SHARES
HEREUNDER). OPTIONEE FURTHER ACKNOWLEDGES AND AGREES THAT THIS AGREEMENT, THE
TRANSACTIONS CONTEMPLATED HEREUNDER AND THE VESTING SCHEDULE SET FORTH HEREIN DO
NOT CONSTITUTE AN EXPRESS OR IMPLIED PROMISE OF CONTINUED ENGAGEMENT AS A
SERVICE PROVIDER FOR THE VESTING PERIOD, FOR ANY PERIOD, OR AT ALL, AND SHALL
NOT INTERFERE IN ANY WAY WITH OPTIONEE'S RIGHT OR THE COMPANY'S RIGHT TO
TERMINATE OPTIONEE'S RELATIONSHIP AS A SERVICE PROVIDER AT ANY TIME, WITH OR
WITHOUT CAUSE.

     Optionee acknowledges receipt of a copy of the Plan and represents that he
or she is familiar with the terms and provisions thereof, and hereby accepts
this Option subject to all of the terms and provisions thereof. Optionee has
reviewed the Plan and this Option in their entirety, has had an opportunity to
obtain the advice of counsel prior to executing this Option and fully
understands all provisions of the Option. Optionee hereby agrees to accept as
binding, conclusive and final all decisions or interpretations of the
Administrator upon any questions arising under the Plan or this Option. Optionee
further agrees to notify the Company upon any change in the residence address
indicated below.

OPTIONEE:                                        TANTAU SOFTWARE, INC.

Signature___________________________             By_____________________________

Print Name__________________________             Title__________________________

____________________________________

____________________________________
Residence Address


                                      -6-

<PAGE>


                                    EXHIBIT A

                                 1999 STOCK PLAN

                                 EXERCISE NOTICE

Tantau Software, Inc.
108 Wild Basin Road, Suite 110
Austin, TX 78746

Attention:  Chief Financial Officer

     1. EXERCISE OF OPTION. Effective as of today, ____________, ____, the
undersigned ("Optionee") hereby elects to exercise Optionee's option (the
"Option") to purchase ________ shares of the Common Stock (the "Shares") of
Tantau Software, Inc. (the "Company") under and pursuant to the 1999 Stock Plan
(the "Plan") and the Stock Option Agreement dated ____________, ____ (the
"Option Agreement").

     2. DELIVERY OF PAYMENT. Purchaser herewith delivers to the Company the full
purchase price of the Shares, as set forth in the Option Agreement.

     3. REPRESENTATIONS OF OPTIONEE. Optionee acknowledges that Optionee has
received, read and understood the Plan and the Option Agreement and agrees to
abide by and be bound by their terms and conditions.

     4. RIGHTS AS SHAREHOLDER. Until the issuance of the Shares (as evidenced by
the appropriate entry on the books of the Company or of a duly authorized
transfer agent of the Company), no right to vote or receive dividends or any
other rights as a shareholder shall exist with respect to the optioned stock,
notwithstanding the exercise of the Option. The Shares shall be issued to the
Optionee as soon as practicable after the Option is exercised. No adjustment
shall be made for a dividend or other right for which the record date is prior
to the date of issuance except as provided in Section 12 of the Plan.

     5. COMPANY'S RIGHT OF FIRST REFUSAL. Before any Shares held by Optionee or
any transferee (either being sometimes referred to herein as the "Holder") may
be sold or otherwise transferred (including transfer by gift or operation of
law), the Company or its assignee(s) shall have a right of first refusal to
purchase the Shares on the terms and conditions set forth in this Section (the
"Right of First Refusal").

          (a) NOTICE OF PROPOSED TRANSFER. The Holder of the Shares shall
deliver to the Company a written notice (the "Notice") stating: (i) the Holder's
bona fide intention to sell or otherwise transfer such Shares; (ii) the name of
each proposed purchaser or other transferee ("Proposed Transferee"); (iii) the
number of Shares to be transferred to each Proposed Transferee; and (iv) the
bona fide cash price or other consideration for which the Holder proposes to
transfer the


<PAGE>

Shares (the "Offered Price"), and the Holder shall offer the Shares at the
Offered Price to the Company or its assignee(s).

          (b) EXERCISE OF RIGHT OF FIRST REFUSAL. At any time within thirty (30)
days after receipt of the Notice, the Company and/or its assignee(s) may, by
giving written notice to the Holder, elect to purchase all, but not less than
all, of the Shares proposed to be transferred to any one or more of the Proposed
Transferees, at the purchase price determined in accordance with subsection (c)
below.

          (c) PURCHASE PRICE. The purchase price ("Purchase Price") for the
Shares purchased by the Company or its assignee(s) under this Section shall be
the Offered Price. If the Offered Price includes consideration other than cash,
the cash equivalent value of the non-cash consideration shall be determined by
the Board of Directors of the Company in good faith.

          (d) PAYMENT. Payment of the Purchase Price shall be made, at the
option of the Company or its assignee(s), in cash (by check), by cancellation of
all or a portion of any outstanding indebtedness of the Holder to the Company
(or, in the case of repurchase by an assignee, to the assignee), or by any
combination thereof within 30 days after receipt of the Notice or in the manner
and at the times set forth in the Notice.

          (e) HOLDER'S RIGHT TO TRANSFER. If all of the Shares proposed in the
Notice to be transferred to a given Proposed Transferee are not purchased by the
Company and/or its assignee(s) as provided in this Section, then the Holder may
sell or otherwise transfer such Shares to that Proposed Transferee at the
Offered Price or at a higher price, provided that such sale or other transfer is
consummated within 120 days after the date of the Notice, that any such sale or
other transfer is effected in accordance with any applicable securities laws and
that the Proposed Transferee agrees in writing that the provisions of this
Section shall continue to apply to the Shares in the hands of such Proposed
Transferee. If the Shares described in the Notice are not transferred to the
Proposed Transferee within such period, a new Notice shall be given to the
Company, and the Company and/or its assignees shall again be offered the Right
of First Refusal before any Shares held by the Holder may be sold or otherwise
transferred.

          (f) EXCEPTION FOR CERTAIN FAMILY TRANSFERS. Anything to the contrary
contained in this Section notwithstanding, the transfer of any or all of the
Shares during the Optionee's lifetime or on the Optionee's death by will or
intestacy to the Optionee's immediate family or a trust for the benefit of the
Optionee's immediate family shall be exempt from the provisions of this Section.
"Immediate Family" as used herein shall mean spouse, lineal descendant or
antecedent, father, mother, brother or sister. In such case, the transferee or
other recipient shall receive and hold the Shares so transferred subject to the
provisions of this Section, and there shall be no further transfer of such
Shares except in accordance with the terms of this Section.

          (g) TERMINATION OF RIGHT OF FIRST REFUSAL. The Right of First Refusal
shall terminate as to any Shares upon the first sale of Common Stock of the
Company to the general public pursuant to a registration statement filed with
and declared effective by the Securities and Exchange Commission under the
Securities Act of 1933, as amended.

                                      -2-

<PAGE>


     6. TAX CONSULTATION. Optionee understands that Optionee may suffer adverse
tax consequences as a result of Optionee's purchase or disposition of the
Shares. Optionee represents that Optionee has consulted with any tax consultants
Optionee deems advisable in connection with the purchase or disposition of the
Shares and that Optionee is not relying on the Company for any tax advice.

     7. RESTRICTIVE LEGENDS AND STOP-TRANSFER ORDERS.

          (a) LEGENDS. Optionee understands and agrees that the Company shall
cause the legends set forth below or legends substantially equivalent thereto,
to be placed upon any certificate(s) evidencing ownership of the Shares together
with any other legends that may be required by the Company or by state or
federal securities laws:

                  THE SECURITIES REPRESENTED HEREBY HAVE NOT BEEN REGISTERED
                  UNDER THE SECURITIES ACT OF 1933 (THE "ACT") AND MAY NOT BE
                  OFFERED, SOLD OR OTHERWISE TRANSFERRED, PLEDGED OR
                  HYPOTHECATED UNLESS AND UNTIL REGISTERED UNDER THE ACT OR, IN
                  THE OPINION OF COMPANY COUNSEL SATISFACTORY TO THE ISSUER OF
                  THESE SECURITIES, SUCH OFFER, SALE OR TRANSFER, PLEDGE OR
                  HYPOTHECATION IS IN COMPLIANCE THEREWITH. THE SHARES
                  REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO CERTAIN
                  RESTRICTIONS ON TRANSFER AND RIGHT OF FIRST REFUSAL OPTIONS
                  HELD BY THE ISSUER OR ITS ASSIGNEE(S) AS SET FORTH IN THE
                  EXERCISE NOTICE BETWEEN THE ISSUER AND THE ORIGINAL HOLDER OF
                  THESE SHARES, A COPY OF WHICH MAY BE OBTAINED AT THE PRINCIPAL
                  OFFICE OF THE ISSUER. SUCH TRANSFER RESTRICTIONS AND RIGHT OF
                  FIRST REFUSAL ARE BINDING ON TRANSFEREES OF THESE SHARES.

          (b) STOP-TRANSFER NOTICES. Optionee agrees that, in order to ensure
compliance with the restrictions referred to herein, the Company may issue
appropriate "stop transfer" instructions to its transfer agent, if any, and
that, if the Company transfers its own securities, it may make appropriate
notations to the same effect in its own records.

          (c) REFUSAL TO TRANSFER. The Company shall not be required (i) to
transfer on its books any Shares that have been sold or otherwise transferred in
violation of any of the provisions of this Exercise Notice or (ii) to treat as
owner of such Shares or to accord the right to vote or pay dividends to any
purchaser or other transferee to whom such Shares shall have been so
transferred.

     8. SUCCESSORS AND ASSIGNS. The Company may assign any of its rights under
this Exercise Notice to single or multiple assignees, and the terms and
conditions of this Exercise Notice shall inure to the benefit of the successors
and assigns of the Company. Subject to the restrictions on transfer herein set
forth, the terms and conditions of this Exercise Notice shall be binding upon
Optionee and his or her heirs, executors, administrators, successors and
assigns.


                                      -3-

<PAGE>


     9. INTERPRETATION. Any dispute regarding the interpretation of this
Exercise Notice shall be submitted by Optionee or by the Company forthwith to
the Administrator which shall review such dispute at its next regular meeting.
The resolution of such a dispute by the Administrator shall be final and binding
on all parties.

     10. GOVERNING LAW; SEVERABILITY. This Exercise Notice is governed by the
internal substantive laws, but not the choice of law rules, of Texas.

     11. ENTIRE AGREEMENT. The Plan and Option Agreement are incorporated herein
by reference. This Exercise Notice, the Plan, the Restricted Stock Purchase
Agreement, the Option Agreement and the Investment Representation Statement
constitute the entire agreement of the parties with respect to the subject
matter hereof and supersede in their entirety all prior undertakings and
agreements of the Company and Optionee with respect to the subject matter
hereof, and may not be modified adversely to the Optionee's interest except by
means of a writing signed by the Company and Optionee.

Submitted by:                              Accepted by:

OPTIONEE:                                  TANTAU SOFTWARE, INC.

Signature   ____________________________   By___________________________________


Print Name  _________________________      Its__________________________________

ADDRESS:                                   ADDRESS:

 _______________________________________   108 Wild Basin Road, Suite 110
 _______________________________________   Austin, TX 78746
 _______________________________________


                                           ____________________________________
                                           Date Received


                                      -4-


<PAGE>


                                    EXHIBIT B

                       INVESTMENT REPRESENTATION STATEMENT

OPTIONEE:                  NAME

COMPANY:                   TANTAU SOFTWARE, INC.

SECURITY:                  COMMON STOCK

AMOUNT:

DATE:

In connection with the purchase of the above-listed Securities, the undersigned
Optionee represents to the Company the following:

         (a) Optionee is aware of the Company's business affairs and financial
condition and has acquired sufficient information about the Company to reach an
informed and knowledgeable decision to acquire the Securities. Optionee is
acquiring these Securities for investment for Optionee's own account only and
not with a view to, or for resale in connection with, any "distribution" thereof
within the meaning of the Securities Act of 1933, as amended (the "Securities
Act").

         (b) Optionee acknowledges and understands that the Securities
constitute "restricted securities" under the Securities Act and have not been
registered under the Securities Act in reliance upon a specific exemption
therefrom, which exemption depends upon, among other things, the bona fide
nature of Optionee's investment intent as expressed herein. In this connection,
Optionee understands that, in the view of the Securities and Exchange
Commission, the statutory basis for such exemption may be unavailable if
Optionee's representation was predicated solely upon a present intention to hold
these Securities for the minimum capital gains period specified under tax
statutes, for a deferred sale, for or until an increase or decrease in the
market price of the Securities, or for a period of one year or any other fixed
period in the future. Optionee further understands that the Securities must be
held indefinitely unless they are subsequently registered under the Securities
Act or an exemption from such registration is available. Optionee further
acknowledges and understands that the Company is under no obligation to register
the Securities. Optionee understands that the certificate evidencing the
Securities will be imprinted with a legend which prohibits the transfer of the
Securities unless they are registered or such registration is not required in
the opinion of counsel satisfactory to the Company, and with any other legend
required under applicable state securities laws.

         (c) Optionee is familiar with the provisions of Rule 701 and Rule 144,
each promulgated under the Securities Act, which, in substance, permit limited
public resale of "restricted securities" acquired, directly or indirectly from
the issuer thereof, in a non-public offering subject to the

<PAGE>

satisfaction of certain conditions. Rule 701 provides that if the issuer
qualifies under Rule 701 at the time of the grant of the Option to the Optionee,
the exercise will be exempt from registration under the Securities Act. In the
event the Company becomes subject to the reporting requirements of Section 13 or
15(d) of the Securities Exchange Act of 1934, ninety (90) days thereafter (or
such longer period as any market stand-off agreement may require) the Securities
exempt under Rule 701 may be resold, subject to the satisfaction of certain of
the conditions specified by Rule 144, including: (1) the resale being made
through a broker in an unsolicited "broker's transaction" or in transactions
directly with a market maker (as said term is defined under the Securities
Exchange Act of 1934); and, in the case of an affiliate, (2) the availability of
certain public information about the Company, (3) the amount of Securities being
sold during any three month period not exceeding the limitations specified in
Rule 144(e), and (4) the timely filing of a Form 144, if applicable. In the
event that the Company does not qualify under Rule 701 at the time of grant of
the Option, then the Securities may be resold in certain limited circumstances
subject to the provisions of Rule 144, which requires the resale to occur not
less than one year after the later of the date the Securities were sold by the
Company or the date the Securities were sold by an affiliate of the Company,
within the meaning of Rule 144; and, in the case of acquisition of the
Securities by an affiliate, or by a non-affiliate who subsequently holds the
Securities less than two years, the satisfaction of the conditions set forth in
sections (1), (2), (3) and (4) of the paragraph immediately above.

         (d) Optionee further understands that in the event all of the
applicable requirements of Rule 701 or 144 are not satisfied, registration under
the Securities Act, compliance with Regulation A, or some other registration
exemption will be required; and that, notwithstanding the fact that Rules 144
and 701 are not exclusive, the Staff of the Securities and Exchange Commission
has expressed its opinion that persons proposing to sell private placement
securities other than in a registered offering and otherwise than pursuant to
Rules 144 or 701 will have a substantial burden of proof in establishing that an
exemption from registration is available for such offers or sales, and that such
persons and their respective brokers who participate in such transactions do so
at their own risk. Optionee understands that no assurances can be given that any
such other registration exemption will be available in such event.

                                    Signature of Optionee:


                                    ______________________________________

                                    Date:___________________________,_____


                                      -2-

<PAGE>


                                   EXHIBIT C-1

                              TANTAU SOFTWARE, INC.

                                 1999 STOCK PLAN

                       RESTRICTED STOCK PURCHASE AGREEMENT

         THIS AGREEMENT is made between NAME (the "Purchaser") and Tantau
Software, Inc. (the "Company") as of ____________, _____.

         Unless otherwise defined herein, the terms defined in the 1999 Stock
Plan shall have the same defined meanings in this Agreement.

                                    RECITALS
         A. Pursuant to the exercise of the option granted to Purchaser under
the Plan and pursuant to the Option Agreement dated Date of Grant by and between
the Company and Purchaser with respect to such grant (the "Option"), which Plan
and Option Agreement are hereby incorporated by reference, Purchaser has elected
to purchase ________ of those shares of Common Stock which have not become
vested under the vesting schedule set forth in the Option Agreement ("Unvested
Shares"). The Unvested Shares and the shares subject to the Option Agreement
which have become vested are sometimes collectively referred to herein as the
"Shares".

         B. As required by the Option Agreement, as a condition to Purchaser's
election to exercise the option, Purchaser must execute this Agreement, which
sets forth the rights and obligations of the parties with respect to Shares
acquired upon exercise of the Option.

         1.       REPURCHASE OPTION.

                (a) If Purchaser's status as a Service Provider is terminated
for any reason, including for cause, death, and Disability, the Company shall
have the right and option to purchase from Purchaser, or Purchaser's personal
representative, as the case may be, all of the Purchaser's Unvested Shares as of
the date of such termination at the price paid by the Purchaser for such Shares
(the "Repurchase Option").

                (b) Upon the occurrence of such termination, the Company may
exercise its Repurchase Option by delivering personally or by registered mail,
to Purchaser (or his transferee or legal representative, as the case may be),
within ninety (90) days of the termination, a notice in writing indicating the
Company's intention to exercise the Repurchase Option and setting forth a date
for closing not later than thirty (30) days from the mailing of such notice. The
closing shall take place at the Company's office. At the closing, the holder of
the certificates for the Unvested Shares being transferred shall deliver the
stock certificate or certificates evidencing the Unvested Shares, and the
Company shall deliver the purchase price therefor.

<PAGE>


                (c) At its option, the Company may elect to make payment for the
Unvested Shares to a bank selected by the Company. The Company shall avail
itself of this option by a notice in writing to Purchaser stating the name and
address of the bank, date of closing, and waiving the closing at the Company's
office.

                (d) If the Company does not elect to exercise the Repurchase
Option conferred above by giving the requisite notice within ninety (90) days
following the termination, the Repurchase Option shall terminate.

                (e) The Repurchase Option shall terminate in accordance with the
vesting schedule contained in Optionee's Option Agreement.

          2.       TRANSFERABILITY OF THE SHARES; ESCROW.

                (a) Purchaser hereby authorizes and directs the Secretary of the
Company, or such other person designated by the Company, to transfer the
Unvested Shares as to which the Repurchase Option has been exercised from
Purchaser to the Company.

                (b) To insure the availability for delivery of Purchaser's
Unvested Shares upon repurchase by the Company pursuant to the Repurchase Option
under Section 1, Purchaser hereby appoints the Secretary, or any other person
designated by the Company as escrow agent, as its attorney-in-fact to sell,
assign and transfer unto the Company, such Unvested Shares, if any, repurchased
by the Company pursuant to the Repurchase Option and shall, upon execution of
this Agreement, deliver and deposit with the Secretary of the Company, or such
other person designated by the Company, the share certificates representing the
Unvested Shares, together with the stock assignment duly endorsed in blank,
attached hereto as EXHIBIT C-2. The Unvested Shares and stock assignment shall
be held by the secretary in escrow, pursuant to the Joint Escrow Instructions of
the Company and Purchaser attached as EXHIBIT C-3 hereto, until the Company
exercises its Repurchase Option, until such Unvested Shares are vested, or until
such time as this Agreement no longer is in effect. As a further condition to
the Company's obligations under this Agreement, the spouse of the Purchaser, if
any, shall execute and deliver to the Company the Consent of Spouse attached
hereto as EXHIBIT C-4. Upon vesting of the Unvested Shares, the escrow agent
shall promptly deliver to the Purchaser the certificate or certificates
representing such Shares in the escrow agent's possession belonging to the
Purchaser, and the escrow agent shall be discharged of all further obligations
hereunder; provided, however, that the escrow agent shall nevertheless retain
such certificate or certificates as escrow agent if so required pursuant to
other restrictions imposed pursuant to this Agreement.

                (c) The Company, or its designee, shall not be liable for any
act it may do or omit to do with respect to holding the Shares in escrow and
while acting in good faith and in the exercise of its judgment.

                (d) Transfer or sale of the Shares is subject to restrictions on
transfer imposed by any applicable state and federal securities laws. Any
transferee shall hold such Shares subject to all the provisions hereof and the
Exercise Notice executed by the Purchaser with respect to any Unvested

                                      -2-

<PAGE>


Shares purchased by Purchaser and shall acknowledge the same by signing a copy
of this Agreement.

         3. OWNERSHIP, VOTING RIGHTS, DUTIES. This Agreement shall not affect in
any way the ownership, voting rights or other rights or duties of Purchaser,
except as specifically provided herein.

         4. LEGENDS. The share certificate evidencing the Shares issued
hereunder shall be endorsed with the following legend (in addition to any legend
required under applicable federal and state securities laws):

            THE SHARES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO CERTAIN
RESTRICTIONS UPON TRANSFER AND RIGHTS OF REPURCHASE AS SET FORTH IN AN AGREEMENT
BETWEEN THE COMPANY AND THE STOCKHOLDER, A COPY OF WHICH IS ON FILE WITH THE
SECRETARY OF THE COMPANY.

         5. ADJUSTMENT FOR STOCK SPLIT. All references to the number of Shares
and the purchase price of the Shares in this Agreement shall be appropriately
adjusted to reflect any stock split, stock dividend or other change in the
Shares which may be made by the Company pursuant to Section 12 of the Plan after
the date of this Agreement.

         6. NOTICES. Notices required hereunder shall be given in person or by
registered mail to the address of Purchaser shown on the records of the Company,
and to the Company at their respective principal executive offices.

         7. SURVIVAL OF TERMS. This Agreement shall apply to and bind Purchaser
and the Company and their respective permitted assignees and transferees, heirs,
legatees, executors, administrators and legal successors.

         8. SECTION 83(b) ELECTION. Purchaser hereby acknowledges that he or she
has been informed that, with respect to the exercise of an Option for Unvested
Shares, an election (the "Election") may be filed by the Purchaser with the
Internal Revenue Service, WITHIN 30 DAYS of the purchase of the exercised
Shares, electing pursuant to Section 83(b) of the Code to be taxed currently on
any difference between the purchase price of the exercised Shares and their Fair
Market Value on the date of purchase. In the case of a Nonstatutory Stock
Option, this will result in a recognition of taxable income to the Purchaser on
the date of exercise, measured by the excess, if any, of the Fair Market Value
of the exercised Shares, at the time the Option is exercised over the purchase
price for the exercised Shares. Absent such an Election, taxable income will be
measured and recognized by Purchaser at the time or times on which the Company's
Repurchase Option lapses. In the case of an Incentive Stock Option, such an
Election will result in a recognition of income to the Purchaser for alternative
minimum tax purposes on the date of exercise, measured by the excess, if any, of
the Fair Market Value of the exercised Shares, at the time the option is
exercised, over the purchase price for the exercised Shares. Absent such an
Election, alternative minimum taxable income will be measured and recognized by
Purchaser at the time or times on which the Company's Repurchase Option lapses.
Purchaser is strongly encouraged to seek the advice of his or her own tax
consultants

                                      -3-

<PAGE>



in connection with the purchase of the Shares and the advisability of filing of
the Election under Section 83(b) of the Code. A form of Election under Section
83(b) is attached hereto as EXHIBIT C-5 for reference.


         PURCHASER ACKNOWLEDGES THAT IT IS PURCHASER'S SOLE RESPONSIBILITY AND
NOT THE COMPANY'S TO FILE TIMELY THE ELECTION UNDER SECTION 83(b) OF THE CODE,
EVEN IF PURCHASER REQUESTS THE COMPANY OR ITS REPRESENTATIVE TO MAKE THIS FILING
ON PURCHASER'S BEHALF.

         9. REPRESENTATIONS. Purchaser has reviewed with his own tax advisors
the federal, state, local and foreign tax consequences of this investment and
the transactions contemplated by this Agreement. Purchaser is relying solely on
such advisors and not on any statements or representations of the Company or any
of its agents. Purchaser understands that he (and not the Company) shall be
responsible for his own tax liability that may arise as a result of this
investment or the transactions contemplated by this Agreement.

         10. GOVERNING LAW. This Agreement shall be governed by the internal
substantive laws, but not the choice of law rules, of Texas.

         Purchaser represents that he has read this Agreement and is familiar
with its terms and provisions. Purchaser hereby agrees to accept as binding,
conclusive and final all decisions or interpretations of the Board upon any
questions arising under this Agreement.

         IN WITNESS WHEREOF, this Agreement is deemed made as of the date first
set forth above.

OPTIONEE:                                TANTAU SOFTWARE, INC.


Signature _________________________      By  _______________________________

Print Name ________________________      Title _____________________________


Residence Address


___________________________________
___________________________________


Dated:_______________________,_____


                                      -4-

<PAGE>


                                   EXHIBIT C-2

                      ASSIGNMENT SEPARATE FROM CERTIFICATE

         FOR VALUE RECEIVED I, NAME, hereby sell, assign and transfer unto
TANTAU SOFTWARE, INC. ______________________________________________________
(__________) shares of the Common Stock of TANTAU SOFTWARE, INC. standing in my
name of the books of said corporation represented by Certificate No. ________
herewith and do hereby irrevocably constitute and appoint
_______________________________________________ to transfer the said stock on
the books of the within named corporation with full power of substitution in the
premises.

         This Stock Assignment may be used only in accordance with the
Restricted Stock Purchase Agreement between TANTAU SOFTWARE, INC. and the
undersigned dated ______________, _____.

Dated:______________________, _______    Signature:____________________________







INSTRUCTIONS: Please do not fill in any blanks other than the signature line.
The purpose of this assignment is to enable the Company to exercise its
"repurchase option," as set forth in the Agreement, without requiring additional
signatures on the part of the Purchaser.



<PAGE>


                                   EXHIBIT C-3

                            JOINT ESCROW INSTRUCTIONS

                                                            _______________, ___

Chief Financial Officer
Tantau Software, Inc.
108 Wild Basin Road, Suite 110
Austin, TX 78746

Attention:  Chief Financial Officer

Dear ____________:

         As Escrow Agent for both Tantau Software, Inc. (the "Company") and the
undersigned purchaser of stock of the Company (the "Purchaser"), you are hereby
authorized and directed to hold the documents delivered to you pursuant to the
terms of that certain Restricted Stock Purchase Agreement ("Agreement") between
the Company and the undersigned, in accordance with the following instructions:

         1. In the event the Company and/or any assignee of the Company
(referred to collectively for convenience herein as the "Company") exercises the
Company's repurchase option set forth in the Agreement, the Company shall give
to Purchaser and you a written notice specifying the number of shares of stock
to be purchased, the purchase price, and the time for a closing hereunder at the
principal office of the Company. Purchaser and the Company hereby irrevocably
authorize and direct you to close the transaction contemplated by such notice in
accordance with the terms of said notice.

         2. At the closing, you are directed (a) to date the stock assignments
necessary for the transfer in question, (b) to fill in the number of shares
being transferred, and (c) to deliver the stock assignments, together with the
certificate evidencing the shares of stock to be transferred, to the Company or
its assignee, against the simultaneous delivery to you of the purchase price (by
cash, a check, or some combination thereof) for the number of shares of stock
being purchased pursuant to the exercise of the Company's repurchase option.

         3. Purchaser irrevocably authorizes the Company to deposit with you any
certificates evidencing shares of stock to be held by you hereunder and any
additions and substitutions to said shares as defined in the Agreement.
Purchaser does hereby irrevocably constitute and appoint you as Purchaser's
attorney-in-fact and agent for the term of this escrow to execute with respect
to such securities all documents necessary or appropriate to make such
securities negotiable and to complete any transaction herein contemplated,
including but not limited to the filing with any applicable state blue sky
authority of any required applications for consent to, or notice of transfer of,
the securities.

<PAGE>


Subject to the provisions of this paragraph 3, Purchaser shall exercise all
rights and privileges of a stockholder of the Company while the stock is
held by you.

         4. Upon written request of the Purchaser, but no more than once per
calendar year, unless the Company's repurchase option has been exercised, you
will deliver to Purchaser a certificate or certificates representing so many
shares of stock as are not then subject to the Company's repurchase option.
Within 120 days after cessation of Purchaser's continuous employment by or
services to the Company, or any parent or subsidiary of the Company, you will
deliver to Purchaser a certificate or certificates representing the aggregate
number of shares held or issued pursuant to the Agreement and not purchased by
the Company or its assignees pursuant to exercise of the Company's repurchase
option.

         5. If at the time of termination of this escrow you should have in your
possession any documents, securities, or other property belonging to Purchaser,
you shall deliver all of the same to Purchaser and shall be discharged of all
further obligations hereunder.

         6. Your duties hereunder may be altered, amended, modified or revoked
only by a writing signed by all of the parties hereto.

         7. You shall be obligated only for the performance of such duties as
are specifically set forth herein and may rely and shall be protected in relying
or refraining from acting on any instrument reasonably believed by you to be
genuine and to have been signed or presented by the proper party or parties. You
shall not be personally liable for any act you may do or omit to do hereunder as
Escrow Agent or as attorney-in-fact for Purchaser while acting in good faith,
and any act done or omitted by you pursuant to the advice of your own attorneys
shall be conclusive evidence of such good faith.

         8. You are hereby expressly authorized to disregard any and all
warnings given by any of the parties hereto or by any other person or
corporation, excepting only orders or process of courts of law and are hereby
expressly authorized to comply with and obey orders, judgments or decrees of any
court. In case you obey or comply with any such order, judgment or decree, you
shall not be liable to any of the parties hereto or to any other person, firm or
corporation by reason of such compliance, notwithstanding any such order,
judgment or decree being subsequently reversed, modified, annulled, set aside,
vacated or found to have been entered without jurisdiction.

         9. You shall not be liable in any respect on account of the identity,
authorities or rights of the parties executing or delivering or purporting to
execute or deliver the Agreement or any documents or papers deposited or called
for hereunder.

         10. You shall not be liable for the outlawing of any rights under the
Statute of Limitations with respect to these Joint Escrow Instructions or any
documents deposited with you.

                                      -2-

<PAGE>


         11. You shall be entitled to employ such legal counsel and other
experts as you may deem necessary properly to advise you in connection with your
obligations hereunder, may rely upon the advice of such counsel, and may pay
such counsel reasonable compensation therefor.

         12. Your responsibilities as Escrow Agent hereunder shall terminate if
you shall cease to be an officer or agent of the Company or if you shall resign
by written notice to each party. In the event of any such termination, the
Company shall appoint a successor Escrow Agent.

         13. If you reasonably require other or further instruments in
connection with these Joint Escrow Instructions or obligations in respect
hereto, the necessary parties hereto shall join in furnishing such instruments.

         14. It is understood and agreed that should any dispute arise with
respect to the delivery and/or ownership or right of possession of the
securities held by you hereunder, you are authorized and directed to retain in
your possession without liability to anyone all or any part of said securities
until such disputes shall have been settled either by mutual written agreement
of the parties concerned or by a final order, decree or judgment of a court of
competent jurisdiction after the time for appeal has expired and no appeal has
been perfected, but you shall be under no duty whatsoever to institute or defend
any such proceedings.

         15. Any notice required or permitted hereunder shall be given in
writing and shall be deemed effectively given upon personal delivery or upon
deposit in the United States Post Office, by registered or certified mail with
postage and fees prepaid, addressed to each of the other parties thereunto
entitled at the following addresses or at such other addresses as a party may
designate by ten days' advance written notice to each of the other parties
hereto.

         16. By signing these Joint Escrow Instructions, you become a party
hereto only for the purpose of said Joint Escrow Instructions; you do not become
a party to the Agreement.

         17. This instrument shall be binding upon and inure to the benefit of
the parties hereto, and their respective successors and permitted assigns.

                                      -3-

<PAGE>


         18. These Joint Escrow Instructions shall be governed by the internal
substantive laws, but not the choice of law rules, of Texas.

PURCHASER:                                TANTAU SOFTWARE, INC.


Signature___________________________      By________________________________


Print Name__________________________      Title_____________________________


Residence Address


____________________________________
____________________________________

ESCROW AGENT


____________________________________
Chief Financial Officer


Dated:_______________________, _____


                                      -4-

<PAGE>


                                   EXHIBIT C-4

                                CONSENT OF SPOUSE

         I, ____________________, spouse of NAME, have read and approve the
foregoing Restricted Stock Purchase Agreement (the "Agreement"). In
consideration of granting of the right to my spouse to purchase shares of Tantau
Software, Inc., as set forth in the Agreement, I hereby appoint my spouse as my
attorney-in-fact in respect to the exercise of any rights under the Agreement
and agree to be bound by the provisions of the Agreement insofar as I may have
any rights in said Agreement or any shares issued pursuant thereto under the
community property laws or similar laws relating to marital property in effect
in the state of our residence as of the date of the signing of the foregoing
Agreement.

Dated:_________________________, _____   Signature:____________________________


                                      -5-

<PAGE>


                                   EXHIBIT C-5
                          ELECTION UNDER SECTION 83(b)
                      OF THE INTERNAL REVENUE CODE OF 1986


     The undersigned taxpayer hereby elects, pursuant to Sections 55 and 83(b)
of the Internal Revenue Code of 1986, as amended, to include in taxpayer's gross
income or alternative minimum taxable income, as the case may be, for the
current taxable year the amount of any compensation taxable to taxpayer in
connection with taxpayer's receipt of the property described below:

1.   The name, address, taxpayer identification number and taxable year of the
     undersigned are as follows:

     NAME:                        TAXPAYER:                     SPOUSE:
     ADDRESS:
     IDENTIFICATION NO.:          TAXPAYER:                     SPOUSE:
     TAXABLE YEAR:

2.   The property with respect to which the election is made is described as
     follows: ____________ shares (the "Shares") of the Common Stock of Tantau
     Software, Inc. (the "Company").

3.   The date on which the property was transferred is: ____________, ____.

4.   The property is subject to the following restrictions:

     The Shares may not be transferred and are subject to forfeiture under the
     terms of an agreement between the taxpayer and the Company. These
     restrictions lapse upon the satisfaction of certain conditions contained in
     such agreement.

5.   The fair market value at the time of transfer, determined without regard to
     any restriction other than a restriction which by its terms will never
     lapse, of such property is: $______________________.

6.   The amount (if any) paid for such property is: $______________________.


The undersigned has submitted a copy of this statement to the person for whom
the services were performed in connection with the undersigned's receipt of the
above-described property. The transferee of such property is the person
performing the services in connection with the transfer of said property.

THE UNDERSIGNED UNDERSTANDS THAT THE FOREGOING ELECTION MAY NOT BE REVOKED
EXCEPT WITH THE CONSENT OF THE Commissioner.

Dated:______________________, _____        ____________________________________
                                           Taxpayer

The undersigned spouse of taxpayer joins in this election.

Dated:______________________, _____        ____________________________________
                                           Spouse


                                      -6-