PART-TIME EMPLOYMENT
 
                            AND TRANSITION AGREEMENT
 
         WHEREAS, Peter Gyenes ("Executive") has been employed as the
President and Chief Executive Officer of Ardent Software, Inc. ("Ardent") and
serves as a member and the Chairman of Ardent's Board of Directors, and
 
         WHEREAS, upon the effectiveness of the merger of Iroquois
Acquisition Corporation, a wholly-owned subsidiary of Informix Corporation
("Informix"), with and into Ardent Software, Inc. (the "Merger"), Ardent will
become a wholly-owned subsidiary of Informix; and
 
         WHEREAS, in connection with the effectiveness of the merger, the
parties desire and agree to enter into a part-time employment relationship by
means of this Agreement;
 
         NOW, THEREFORE, this Employment Transition Agreement ("Agreement")
is made by and between Informix Software, Inc. (the "Company"), a
wholly-owned subsidiary of Informix, and the Executive effective on the
effective date of the merger (the "Employment Transition Date") as defined in
the Agreement and Plan of Reorganization, effective as of November 30, 1999,
among Informix, Ardent, and Iroquois Acquisition Corporation.
 
         1.  DURATION AND OBLIGATIONS OF PART-TIME EMPLOYMENT RELATIONSHIP.
 
                  (a)  DURATION OF PART-TIME EMPLOYMENT.  On and after the
Employment Transition Date, the Company agrees to employ the Executive as a
common-law employee on a part-time basis for the period of one year from the
Employment Transition Date, unless Executive is terminated earlier (the
period of Executive's part-time employment hereunder is referred to as the
"Part-Time Employment Period"). In this capacity, Executive shall report to
the Chief Executive Officer of the Company (the "CEO"). Executive's duties
shall consist of, among other duties reasonably assigned by the CEO,
including assisting with the integration of Ardent into Informix and related
matters.
 
                  (b)  OBLIGATIONS.  During the Part-Time Employment Period,
Executive shall devote substantial business efforts and time (on a part-time
basis) to the Company. During the Part-Time Employment Period, Executive
agrees to comply with the standard and policies contained in the Informix
Worldwide Ethics Policy (the "Policy") and not to engage actively in any
other employment, occupation or consulting activity for any direct or
indirect remuneration without the prior approval of the CEO which approval
shall be consistent with the Policy; provided, however, that Executive may
serve in any capacity with any civic, educational or charitable organization
without the approval of the CEO, so long as such activities do not interfere
with his duties and obligations under this Agreement; provided, further that
Executive may sit on the boards of directors of corporations and committees
thereof without violating his obligations hereunder, and consistent with the
Policy, a copy of which has been provided to Executive.
 
<PAGE>
 
         2.  EMPLOYEE VACATION AND BENEFITS.  During the Part-Time Employment
Period, Executive shall be entitled to vacation in accordance with the
Company's current policies, and shall be eligible to participate in the
employee benefit plans maintained by the Company to the extent provided for
full-time employees of the Company as permitted by applicable law and
pursuant to the terms and conditions of those plans.
 
         3.  AT-WILL EMPLOYMENT.  Executive and the Company understand and
acknowledge that Executive's employment with the Company is "at-will."
Executive and the Company acknowledge that the part-time employment
relationship may be terminated at any time, with or without good cause or for
any or no cause, at the option either of the Company or Executive.
 
         4.  COMPENSATION.
 
                  During the Part-Time Employment Period, and subject to his
continued part-time employment, the Company shall pay the Executive as
compensation for his services an annual base salary in the amount of One
Hundred and Fifty-Thousand Dollars ($150,000), paid bimonthly according to
the Company's usual payroll practices, less all applicable withholding taxes.
 
         5.  SEVERANCE BENEFITS WITHIN OR AT THE CONCLUSION OF ONE YEAR OF
EFFECTIVE DATE.
 
                  Executive shall be entitled to receive benefits set forth
in Ardent's "Policy Regarding Termination of Executive Status and Related
Matters in the Event of a Sale of the Company," adopted July 29, 1996, as
amended on July 22, 1998 (the "Ardent Severance Policy"), a copy of which is
Attachment A to this Agreement, on the first to occur of (i) termination for
any reason by either Executive or the Company of Executive's employment
during the Part-Time Employment Period or (ii) at the end of the one year
period hereunder.
 
         6.  EXPENSES.  During the Part-Time Employment Period, the Company
will pay or reimburse Executive for reasonable travel, entertainment or other
expenses incurred by Executive in the furtherance of or in connection with
the performance of Executive's duties hereunder in accordance with the
Company's established policies. Executive shall furnish the Company with
evidence of such expenses within a reasonable period of time from the date
that they were incurred.
 
         7.  DEATH OR DISABILITY OF EXECUTIVE.  If Executive dies or becomes
permanently and totally disabled during the term of this Agreement, this
Agreement shall terminate immediately.
 
         8.  EXECUTION OF CONFIDENTIALITY/OWNERSHIP/NONSOLICITATION
AGREEMENT.  As a condition of entering into this Agreement and of receiving
the benefits hereunder, Executive agrees to execute the Informix Employee
Confidentiality/Ownership/Nonsolicitation Agreement.
 
         9.  EXECUTION OF RELEASE AGREEMENT UPON TERMINATION.  As a condition
of entering into this Agreement and of receiving benefits hereunder,
Executive agrees to execute a release of claims agreement substantially in
the form of Attachment B to this Agreement upon the termination of his
employment with the Company.
 
                                        -2-
<PAGE>
 
         10.  ASSIGNMENT.  This Agreement shall be binding upon and inure to
the benefit of (a) the heirs, executors and legal representatives of
Executive upon Executive's death and (b) any successor of the Company. Any
such successor of the Company shall be deemed substituted for the Company
under the terms of this Agreement for all purposes. As used herein,
"successor" shall include any person, firm, corporation or other business
entity which at any time, whether by purchase, merger or otherwise, directly
or indirectly acquires all or substantially all of the assets or business of
the Company. None of the rights of Executive to receive any form of
compensation payable pursuant to this Agreement shall be assignable or
transferable except through a testamentary disposition or by the laws of
descent and distribution upon the death of Executive following termination
without cause. Any attempted assignment, transfer, conveyance or other
disposition (other than as aforesaid) of any interest in the rights of
Executive to receive any form of compensation hereunder shall be null and
void.
 
         11.  NOTICES.  All notices, requests, demands and other
communications called for hereunder shall be in writing and shall be deemed
given if delivered personally or by facsimile or one (1) day after being sent
by Federal Express overnight service or a similar commercial delivery
service, prepaid and addressed to the parties or their successors in interest
at the following addresses:
 
         If to the Company:       Informix Corporation
                                  4100 Bohannon Drive
                                  Menlo Park, CA  94025
                                  Attn:  General Counsel
 
         If to Executive:         Peter Gyenes
                                  at the last residential address
                                  known by the Company.
 
         12.  ARBITRATION.
 
                  (a)  To the extent permitted by law, any dispute or
controversy arising out of, relating to, or in connection with this
Agreement, or the interpretation, validity, construction, performance,
breach, or termination thereof shall be settled by arbitration to be held in
San Mateo County, California, in accordance with the National Rules for the
Resolution of Employment Disputes then in effect of the American Arbitration
Association (the "Rules"). The decision of the arbitrator shall be final,
conclusive and binding on the parties to the arbitration. Judgment may be
entered on the arbitrator's decision in any court having jurisdiction.
 
                  (b)  The arbitrator shall apply California law to the
merits of any dispute or claim, without reference to rules of conflict of
law. The arbitration proceedings shall be governed by federal arbitration law
and by the Rules, without reference to state arbitration law. With respect to
any actions or proceedings to compel arbitration, enforce any arbitration
award or appeal any arbitration award related to this Agreement, the parties
hereto expressly consent to the personal jurisdiction of the state and
federal courts located in California.
 
                  (c)  The Company and Executive shall each pay one-half of
the costs and expenses of such arbitration, and shall separately pay its
counsel fees and expenses.
 
                                        -3-
<PAGE>
 
                  (d)  THE PARTIES HAVE READ AND UNDERSTAND SECTION 12, WHICH
DISCUSSES ARBITRATION. THE PARTIES UNDERSTAND THAT BY SIGNING THIS AGREEMENT,
THEY AGREE, TO THE EXTENT PERMITTED BY LAW, TO SUBMIT ANY FUTURE CLAIMS
ARISING OUT OF, RELATING TO, OR IN CONNECTION WITH THIS AGREEMENT, OR THE
INTERPRETATION, VALIDITY, CONSTRUCTION, PERFORMANCE, BREACH, OR TERMINATION
THEREOF TO BINDING ARBITRATION, AND THAT THIS ARBITRATION CLAUSE CONSTITUTES
A WAIVER OF THEIR RIGHT TO A JURY TRIAL AND RELATES TO THE RESOLUTION OF ALL
DISPUTES, INCLUDING AS TO DISCRIMINATION, RELATING TO ALL ASPECTS OF THE
EMPLOYER/EMPLOYEE RELATIONSHIP.
 
         13.  SEVERABILITY.  In the event that any provision hereof becomes
or is declared by a court of competent jurisdiction to be illegal,
unenforceable or void, this Agreement shall continue in full force and effect
without said provision.
 
         14.  ENTIRE AGREEMENT.  This Agreement, the Ardent Severance Policy,
and the Confidentiality/Ownership/ Nonsolicitation agreement between
Executive and the Company, represent the entire agreement and understanding
between the Company and Executive concerning Executive's employment
relationship with the Company, and supersede and replace in their entirety
any and all prior agreements and understandings concerning Executive's
employment relationship with the Company.
 
         15.  NO ORAL MODIFICATION, CANCELLATION OR DISCHARGE.  This
Agreement may only be amended, canceled or discharged in writing signed by
Executive and an authorized officer of the Company.
 
         16.  GOVERNING LAW.  This Agreement shall be governed by the laws of
the State of California.
 
         17.  ACKNOWLEDGMENT.  Executive acknowledges that he has had the
opportunity to discuss this matter with and obtain advice from his private
attorney, has had sufficient time to, and has carefully read and fully
understands all the provisions of this Agreement, and is knowingly and
voluntarily entering into this Agreement.
 
         18.  TAX TREATMENT.  Payment of the compensation set forth herein
shall be subject to standard employment and income tax withholding.
 
 
 
                                        -4-
<PAGE>
 
         IN WITNESS WHEREOF, the undersigned have executed this Agreement on
the respective dates set forth below
 
         INFORMIX SOFTWARE, INC
 
 
         Date:     3/28/2000                        /s/Gary Lloyd
              --------------------------            ---------------------------
 
 
 
         EXECUTIVE
 
 
         Date:                                      /s/Peter Gyenes
              --------------------------            ---------------------------
                                                    Peter Gyenes
 
<DOCUMENT>
<TYPE>EX-10.78
<SEQUENCE>4
<FILENAME>a2029562zex-10_78.txt
<DESCRIPTION>EX-10-78
<TEXT>
 
<PAGE>
 
                                                                   EXHIBIT 10.78
 
 
                              INFORMIX CORPORATION
 
                    CHANGE OF CONTROL AND SEVERANCE AGREEMENT
 
 
 
 
          This Change of Control and Severance Agreement (the "Agreement") is
made and entered into by and between Peter Gyenes (the "Executive") and Informix
Corporation (the "Company"), effective as of the last date set forth by the
signatures of the parties below (the "Effective Date").
 
                                    RECITALS
 
          A.        It is expected that the Company from time to time will
consider the possibility of an acquisition by another company or other Change of
Control (as defined below). The Board of Directors of the Company (the "Board")
recognizes that such consideration, and the possibility that the Executive's
employment could be terminated by the Company for a reason other than for cause,
can be distractions to the Executive and can cause the Executive to consider
alternative employment opportunities. The Board has determined that it is in the
best interests of the Company and its stockholders to assure that the Company
will have the continued dedication and objectivity of the Executive,
notwithstanding the possibility, threat or occurrence of a Change of Control of
the Company or the termination by the Company of the Executive's employment for
a reason other than for cause.
 
          B.        The Board believes that it is in the best interests of the
Company and its stockholders to provide the Executive with an incentive to
continue his or her employment with the Company, or a wholly-owned subsidiary of
the Company, as the case may be, and to motivate the Executive to maximize the
value of the Company upon a Change of Control for the benefit of its
stockholders.
 
          C.        The Board believes that it is imperative to provide the
Executive with certain benefits upon a Change of Control or upon the termination
by the Company of the Executive's employment for a reason other than cause,
thereby encouraging the Executive to remain with the Company notwithstanding the
possibility of a Change of Control or termination of employment for a reason
other than for cause.
 
          The Company and the Executive hereby agree as follows:
 
          1.        TERM OF AGREEMENT. This Agreement shall terminate upon the
date that all obligations of the Company and the Executive with respect to this
Agreement have been satisfied.
 
<PAGE>
 
          2.        AT-WILL EMPLOYMENT. The Company and the Executive
acknowledge that the Executive's employment is and shall continue to be at-will,
as defined under applicable law, and may be terminated at any time by either
party, with or without cause.
 
          3.        CHANGE OF CONTROL. In the event a Change of Control occurs
within six months following the effective date of options granted to the
Executive to purchase the Company's common stock, and if the Executive is
employed by the Company as of the date of the Change of Control, the Executive's
stock options shall have their vesting accelerated as to two years' additional
vesting. In the event that stock option vesting is accelerated pursuant to the
preceding sentence, the remaining stock options, if any, shall continue to vest
at a monthly rate equal to the total number of shares originally subject to the
option divided by the number of months in the original vesting schedule. In the
event a Change of Control occurs on or after six months following the effective
date of options granted to the Executive to purchase the Company's common stock,
and if the Executive is employed by the Company as of the date of the Change of
Control, the Executive's Stock Options shall have their vesting accelerated in
full so as to become 100% vested.
 
          For the purposes of this Agreement, "Change of Control" shall mean:
 
                    (a)       the approval by the stockholders of the Company of
a merger or consolidation of the Company with any other corporation, other than
a merger or consolidation which would result in the voting securities of the
Company outstanding immediately prior thereto continuing to represent (either by
remaining outstanding or by being converted into voting securities of the
surviving entity) fifty percent (50%) or more of the total voting power
represented by the voting securities of the Company or such surviving entity
outstanding immediately after such merger or consolidation; or
 
                    (b)       any approval by the stockholders of the Company of
a plan of complete liquidation of the Company or an agreement for the sale or
disposition by the Company of all or substantially all of the Company's assets;
or
 
                    (c)       any "person" (as that term is used in Sections
13(d) and 14(d) of the Securities Exchange Act of 1934, as amended) becoming the
"beneficial owner" (as defined in Rule 13d-3 under the Securities Exchange Act
of 1934, as amended), directly or indirectly, of securities of the Company
representing 50% or more of the total voting power represented by the Company's
then outstanding voting securities; or
 
                    (d)       a change in the composition of the Board, as a
result of which fewer than a majority of the directors are Incumbent Directors.
"Incumbent Directors" shall mean directors who either: (a) are directors of the
Company as of the Effective Date; or (b) are elected, or nominated for election,
to the Board with the affirmative votes of at least a majority of those
directors whose election or nomination was not in connection with any
transaction described in subsections (a), (b), or (c) above, or in connection
with an actual or threatened proxy contest relating to the election of directors
of the Company.
 
 
 
                                       -2-
<PAGE>
 
 
          4.        GOLDEN PARACHUTE EXCISE TAXES. Anything in this Agreement to
the contrary notwithstanding, in the event it shall be determined that any
payment or distribution, or any acceleration of vesting of any benefit or award,
by the Company or its affiliated companies to or for the benefit of the
Executive, payable within the meaning of Section 280G of the Internal Revenue
Code (the "Code") (whether paid or payable, distributed or distributable or
accelerated or subject to acceleration pursuant to the terms of this Agreement
or otherwise, but determined without regard to any additional payments required
under this Section 4) (a "Payment") would be subject to the excise tax imposed
by Section 4999 of the Code, or any interest or penalties are incurred by the
Executive with respect to such excise tax (such excise tax, together with any
such interest and penalties, are hereinafter collectively referred to as the
"Excise Tax"), then the Executive shall be entitled to receive an additional
payment (a "Gross-Up Payment") on an amount such that after payment by the
Executive of all taxes imposed upon the Gross-Up Payment and any interest or
penalties imposed with respect to such taxes, the Executive retains an amount of
the Gross-Up Payment equal to the sum of: (a) the Excise Tax imposed upon the
Payments; and (b) the product of any deductions disallowed because of the
inclusion of the Gross-Up Payment in the Executive's adjusted gross income and
the highest applicable marginal rate of federal income taxation for the calendar
year in which the Gross-Up Payment is to be made. For purposes of determining
the amount of the Gross-Up Payment, the Executive shall be deemed to have: (a)
paid federal income taxes at the highest marginal rates of federal income
taxation for the calendar year in which the Gross-Up Payment is to be made; (b)
paid applicable state and local income taxes at the highest rate of taxation for
the calendar year in which the Gross-Up Payment is to be made, net of the
maximum reduction in federal income taxes which could be obtained from deduction
of such state and local taxes; and (c) otherwise allowable deductions for
federal income tax purposes at least equal to those which would be disallowed
because of the inclusion of the Gross-Up Payment in the Executive's adjusted
gross income. The payment of a Gross-Up Payment under this Section 4 shall in no
event be conditioned upon the Executive's termination of employment or the
receipt of severance benefits under this Agreement.
 
          5.        SEVERANCE.
 
                    (a)       If, within one year of a Change of Control, the
Executive's employment is terminated either by the Executive for any reason or
by the surviving entity for any reason other than for Cause (as defined below),
the Executive shall receive severance in the amount of two years' base salary
plus two years' on target earnings.
 
                    (b)       If the Executive's employment is terminated by the
Company for any reason other than for Cause, the Executive shall receive
severance in the amount of two years' base salary.
 
 
                                       -3-
<PAGE>
 
                    (c)       If the Executive's employment is terminated by the
Company for Cause, or the Executive voluntarily resigns, the Executive shall not
receive severance.
 
                    (d)       For purposes of this Agreement, "Cause" shall mean
the occurrence of one or more of the following: (i) Executive's conviction by,
or entry of a plea of guilty or NOLO CONTENDERE in, a court of competent
jurisdiction for any crime which constitutes a felony in the jurisdiction in
which the conduct alleged to constitute the felony occurred; (ii) Executive's
misappropriation of funds or property or commission of an act of fraud, whether
prior or subsequent to the Effective Date; (iii) gross negligence or
recklessness by the Executive in the scope of the Executive's services to the
Company; (iv) a breach by the Executive of a material provision of this
Agreement which is not cured within 30 days of notice; (v) a willful failure by
the Executive substantially to perform his or her duties and responsibilities as
an employee after notice of such failure; or (vi) a material breach by the
Executive of the Company's policies or procedures.
 
          6.        ATTORNEY FEES, COSTS AND EXPENSES. The Company promptly
shall reimburse the Executive, on a monthly basis, for the reasonable attorney
fees, costs and expenses incurred by the Executive in connection with any action
brought by Executive to enforce his or her rights under this Agreement,
regardless of the outcome of the action.
 
          7.        SUCCESSORS.
 
                    (a)       COMPANY'S SUCCESSORS. Any successor to the Company
(whether direct or indirect and whether by purchase, merger, consolidation,
liquidation or otherwise) to all or substantially all of the Company's business
and/or assets shall assume the obligations under this Agreement and agree
expressly to perform the obligations under this Agreement in the same manner and
to the same extent as the Company would be required to perform such obligations
in the absence of a succession. For all purposes under this Agreement, the term
"Company" shall include any successor to the Company's business and/or assets
which executes and delivers the assumption agreement described in this Section
5(a), or which becomes bound by the terms of this Agreement by operation of law.
 
                    (b)       EXECUTIVE'S SUCCESSORS. The terms of this
Agreement and all rights of the Executive hereunder shall inure to the benefit
of, and be enforceable by, the Executive's personal or legal representatives,
executors, administrators, heirs, distributees, devisees and legatees.
 
          8.        MISCELLANEOUS PROVISIONS.
 
                    (a)       WAIVER. No provision of this Agreement shall be
modified, waived or discharged unless the modification, waiver or discharge is
agreed to in writing and signed by the Executive and by an authorized officer of
the Company (other than the Executive). No waiver by either party of any breach
of, or of compliance with, any
 
 
                                       -4-
<PAGE>
 
condition or provision of this Agreement by the other party shall be considered
a waiver of any other condition or provision or of the same condition or
provision at another time.
 
                    (b)       WHOLE AGREEMENT. No agreements, representations or
understandings (whether oral or written and whether express or implied) which
are not expressly set forth in this Agreement have been made or entered into by
either party with respect to the subject matter hereof. This Agreement
represents the entire understanding of the Company and the Executive with
respect to the subject matter of this Agreement and this Agreement supersedes
all prior agreements, arrangements and understandings regarding the subject
matter of this Agreement. If stock option vesting acceleration is triggered
pursuant to this Agreement, the Executive agrees that he or she shall not be
entitled to any additional stock option vesting pursuant to a prior agreement,
arrangement or understanding.
 
                    (c)       CHOICE OF LAW. The validity, interpretation,
construction and performance of this Agreement shall be governed by the laws of
the State of California.
 
                    (d)       SEVERABILITY. The invalidity or unenforceability
of any provision or provisions of this Agreement shall not affect the validity
or enforceablity of any other provision hereof, which shall remain in full force
and effect.
 
                    (e)       COUNTERPARTS. This Agreement may be executed in
counterparts, each of which shall be deemed an original, but all of which
together will constitute one and the same instrument.
 
          IN WITNESS WHEREOF, each of the parties has executed this Agreement,
in the case of the Company by its duly authorized officer, as of the day and
year set forth below.
 
 
COMPANY                                     INFORMIX CORPORATION
 
                                            /s/ Gary Lloyd
                                            ------------------------------
 
 
                                            Dated:  Effective August 28, 2000
 
 
EXECUTIVE                                   /s/ Peter Gyenes
                                            ------------------------------
 
                                            Dated:  Effective August 28, 2000
 
 
                                       -5-
 
</TEXT>
</DOCUMENT>