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                                                                   Exhibit 10.38

                         PERITUS SOFTWARE SERVICES, INC.

                         Common Stock Purchase Agreement

      This Common Stock Purchase Agreement (this "Agreement") dated as of
March 27, 2000 is entered into by and between Peritus Software Services, Inc.,
a Massachusetts corporation (the "Company"), and Rocket Software, Inc. (the
"Purchaser"). The Company and the Purchaser are sometimes referred to herein
each as a "Party" and together as the "Parties".

      In consideration of the mutual promises and covenants contained in this
Agreement, the Parties agree as follows:

      1. Sale of Shares. Subject to the terms and conditions of this Agreement,
at the Closing the Company will sell and issue to the Purchaser, and the
Purchaser will purchase, 10,000,000 shares of the Company's common stock, $.01
par value per share (the "Common Stock"), for an aggregate purchase price of
$4,000,000 (the "Purchase Price"), or $.40 per share. The shares of Common Stock
sold under this Agreement are referred to herein as the "Shares".

      2. The Closing. The closing (the "Closing") of the sale and purchase of
the Shares under this Agreement shall take place at the offices of Hale and Dorr
LLP, 60 State Street, Boston, Massachusetts at approximately 12:00 p.m. on March
27, 2000 or at such other time, date and place as are mutually agreeable to the
Company and the Purchaser. At the Closing, the Company shall deliver to the
Purchaser a certificate for the Shares, registered in the name of the Purchaser,
against payment to the Company of the Purchase Price, by wire transfer of
immediately available funds to an account designated by the Company. The date of
the Closing is hereinafter referred to as the "Closing Date".

      3. Representations of the Company. Except as disclosed by the Company in
the Disclosure Schedule delivered by the Company to the Purchaser herewith (the
"Disclosure Schedule") or in the Company Reports (as defined in Section 3.6 of
this Agreement), the Company hereby represents and warrants to the Purchaser as
follows:

            3.1 Organization and Authority. The Company is a corporation duly
organized, validly existing and in good standing under the laws of the
Commonwealth of Massachusetts, and has requisite power and authority to own its
properties and to carry on its business as now being conducted. The Company has
full power to execute, deliver and perform this Agreement and the Registration
Rights Agreement appended to this Agreement as Annex A (the "Registration Rights
Agreement") and to consummate the transactions contemplated hereby and thereby.
The Company is duly qualified to do business as a foreign corporation and is in
good standing in every jurisdiction in which the failure so to qualify could
reasonably be expected to have a material adverse effect on the business,
properties, assets or condition (financial or otherwise) of the Company (a
"Material Adverse Effect").
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            3.2 Capitalization. The authorized capital stock of the Company
consists of (i) 50,000,000 shares of Common Stock, of which 17,239,971 shares
were issued and outstanding as of March 17, 2000, and (ii) 5,000,000 shares of
preferred stock, $.01 par value per share, of which no shares are issued and
outstanding. All of the outstanding shares of capital stock of the Company have
been duly and validly issued and are fully paid and nonassessable. The
Disclosure Schedule contains a complete and correct description of the
percentage ownership of each subsidiary of the Company and, to the extent not
wholly owned by the Company, beneficially and of record, the names (and the
percentage ownership) of the other owners thereof. There are no outstanding
preemptive, conversion or other rights, options, warrants or agreements granted
or issued by or binding upon the Company or any of its subsidiaries for the
purchase or acquisition of any shares of its capital stock.

            3.3 Issuance of Shares. The issuance, sale and delivery of the
Shares in accordance with this Agreement has been, or will be on or prior to the
Closing, duly authorized by all necessary corporate action on the part of the
Company. The Shares when so issued, sold and delivered against payment therefor
in accordance with the provisions of this Agreement will be duly and validly
issued, fully paid and nonassessable.

            3.4 Authorization. The execution and delivery of this Agreement and
the Registration Rights Agreement by the Company and the consummation by the
Company of all transactions contemplated hereby, have been duly authorized by
all requisite corporate action on the part of the Company. This Agreement and
the Registration Rights Agreement, assuming the due execution and delivery by
the parties thereto other than the Company, constitute the valid and legally
binding obligations of the Company, enforceable against the Company in
accordance with their respective terms subject as to enforcement of remedies to
applicable bankruptcy, insolvency, reorganization, moratorium or similar laws
affecting generally the enforcement of creditors' rights and subject to a
court's discretionary authority with respect to the granting of a decree
ordering specific performance or other equitable remedies. The execution,
delivery and performance of this Agreement and the Registration Rights
Agreement, and the consummation by the Company of the transactions contemplated
hereby and thereby, will not, with or without the giving of notice or the
passage of time or both, (a) violate the provisions of the charter or bylaws of
the Company; (b) violate any judgment, decree, order or award of any court,
governmental body or arbitrator applicable to the Company; or (c) conflict with
or result in the breach or termination of any term or provision of, or
constitute a default under, or cause any acceleration under, or cause the
creation of any lien, charge or encumbrance upon the properties or assets of the
Company pursuant to, any indenture, mortgage, deed of trust or other agreement
or instrument to which it or its properties is a party or by which the Company
is bound, except, with respect to the immediately preceding clauses (a), (b) and
(c), in cases where such violations, conflicts, breaches or terminations could
not reasonably be expected to result in a Material Adverse Effect. Schedule 3.4
to the Disclosure Schedule sets forth a true, correct and complete list of all
consents and approvals of third parties that are required in connection with the
consummation by the Company of the transactions contemplated by this Agreement,
except for such consents and approvals the failure of the Company to receive
could not reasonably be expected to result in a Material Adverse Effect.

            3.5 Governmental Consents. No consent, approval, order or
authorization of, or registration, qualification, designation, declaration or
filing with, any governmental entity is


                                      -2-
<PAGE>

required on the part of the Company in connection with the execution and
delivery of this Agreement or the Registration Rights Agreement, the offer,
issuance, sale and delivery of the Shares or the other transactions to be
consummated at the Closing, as contemplated by this Agreement and the
Registration Rights Agreement, except such filings as shall have been made prior
to and shall be effective on and as of the Closing, such filings required to be
made after the Closing under applicable federal and state securities laws and
such filings the failure to be made could not reasonably be expected to result
in a Material Adverse Effect. Based on the representations made by the Purchaser
in Section 4 of this Agreement, the offer and sale of the Shares to the
Purchaser will be in compliance with applicable federal and state securities
laws.

            3.6 Reports and Financial Statements. The Company has made available
to the Purchaser complete and accurate copies, as amended or supplemented, of
its (a) Quarterly Reports on Form 10-Q for the fiscal quarters ended March 31,
1999, June 30, 1999 and September 30, 1999, as filed with the Securities and
Exchange Commission (the "Commission"), (b) Current Reports on Form 8-K dated
February 9, 1999, February 18, 1999, March 29, 1999, April 2, 1999, May 10,
1999, June 4, 1999 and July 2, 1999 and (c) Annual Report on Form 10-K for the
fiscal year ended December 31, 1998, as amended, (such reports described in the
immediately preceding clauses (a), (b) and (c) are collectively referred to
herein as the "Company Reports"). The Company Reports constitute all of the
documents required to be filed by the Company under Section 13 of the Securities
Exchange Act of 1934, as amended (the "Exchange Act"), with the Commission since
December 31, 1998. As of their respective dates, the Company Reports did not
contain any untrue statement of a material fact or omit to state a material fact
required to be stated herein or necessary to make the statements therein, in
light of the circumstances under which they were made, not misleading. Since the
date of the latest filed Company Report, the Company has not been required to
file a Current Report on Form 8-K under the Exchange Act. The audited financial
statements and unaudited interim financial statements of the Company included in
the Company Reports (i) comply in all material respects with applicable
accounting requirements and the published rules and regulations of the
Commission with respect thereto, (ii) have been prepared in accordance with
United States generally accepted accounting principles ("GAAP") applied on a
consistent basis throughout the periods covered thereby (except as may be
indicated therein or in the notes thereto, and in the case of quarterly
financial statements, as permitted by Form 10-Q under the Exchange Act), (iii)
fairly present the consolidated financial condition, results of operations and
cash flows of the Company as of the respective dates thereof and for the periods
referred to therein, and (iv) are substantially consistent with the books and
records of the Company.

            3.7 No Material Adverse Change. Since September 30, 1999: (i) there
has been no material adverse change to the business, properties, assets or
condition (financial or otherwise) of the Company; (ii) the Company and its
subsidiaries, considered as one entity, have not incurred any material liability
or obligation, indirect, direct or contingent, not in the ordinary course of
business nor entered into any material transaction or agreement not in the
ordinary course of business; and (iii) there has been no dividend or
distribution of any kind declared, paid or made by the Company or, except for
dividends paid to the Company or any of its subsidiaries on any class of capital
stock or repurchase or redemption by the Company or any of its subsidiaries of
any class of capital stock.


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            3.8 Litigation. The Company is not a party to, or to the knowledge
of the Company threatened with, and none of its assets are subject to, any
litigation, suit, action, investigation, proceeding or controversy before any
court, administrative agency or other governmental authority relating to or
affecting its assets or the business or condition (financial or otherwise) of
the Company the outcome of which could reasonably be expected to have a Material
Adverse Effect. The Company is not in violation of or in default with respect to
any judgment, order, writ, injunction, decree or rule of any court,
administrative agency or governmental authority or any regulation of any
administrative agency or governmental authority, which such violation or default
could reasonably be expected to have a Material Adverse Effect.

            3.9 Intellectual Property Rights. The Company and its subsidiaries
own or possess sufficient trademarks, trade names, patent rights, copyrights,
licenses, approvals, trade secrets and other similar rights (collectively,
"Intellectual Property Rights") reasonably necessary to conduct their businesses
as now conducted; and the expected expiration of any of such Intellectual
Property Rights could not reasonably be expected to result in a Material Adverse
Effect. Neither the Company nor any of its subsidiaries has received any notice
of infringement or conflict with asserted intellectual property rights of
others, which infringement or conflict, if the subject of an unfavorable
decision, could reasonably be expected to result in a Material Adverse Effect.

            3.10 Employees. To the Company's knowledge, no employee of the
Company or any of its subsidiaries, is in violation of any material term of any
employment contract, patent disclosure agreement or non-competition agreement
with the Company. There is no pending or, to the Company's knowledge, threatened
action, suit, proceeding or claim, or to its knowledge any basis thereof or
threat thereof, with respect to any contract, agreement, covenant or obligation
referred to in the preceding sentence. The Company does not have any collective
bargaining agreement covering any of its employees.

            3.11 All Necessary Permits, etc. The Company and each subsidiary
possess such valid and current certificates, authorizations or permits issued by
the appropriate state, federal or foreign regulatory agencies or bodies
necessary to conduct their respective businesses, unless the failure to possess
such certificates, authorizations or permits could not reasonably be expected to
have a Material Adverse Effect. Neither the Company nor any subsidiary has
received any notice of proceedings relating to the revocation or modification
of, or noncompliance with, any such certificate, authorization or permit which,
singly or in the aggregate, if the subject of an unfavorable decision, ruling or
finding, could reasonably be expected to result in a Material Adverse Effect.

            3.12 Title to Properties. The Company and each of its subsidiaries
has good and valid title to all the properties and assets reflected as owned in
the Company Reports, in each case free and clear of any security interests,
mortgages, liens, encumbrances, equities, claims and other defects, except such
as do not materially and adversely affect the value of such property and do not
materially interfere with the use made or proposed to be made of such property
by the Company or such subsidiary. The real property, improvements, equipment
and personal property held under lease by the Company or any subsidiary are held
under valid and enforceable leases, with such exceptions as are not material and
do not materially interfere with the use made


                                      -4-
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or proposed to be made of such real property, improvements, equipment or
personal property by the Company, or such subsidiary.

            3.13 Tax Law Compliance. The Company and its consolidated
subsidiaries have filed all necessary federal, state and foreign income and
franchise tax returns and have paid all taxes required to be paid by any of them
and, if due and payable, any related or similar assessment, fine or penalty
levied against any of them, except for assessments, fines or penalties contested
in good faith for which adequate reserves have been provided to the extent
required by GAAP or which the failure to so pay could not reasonably be expected
to result in a Material Adverse Effect. The Company has made adequate charges,
accruals and reserves reasonably determined by the Company in the applicable
financial statements in the Company Reports in respect of all federal, state and
foreign income and franchise taxes for all periods as to which the tax liability
of the Company or any of its consolidated subsidiaries has not been finally
determined.

            3.14 Insurance. The Company and its subsidiaries are insured by
recognized institutions with policies in such amounts and with such deductibles
and covering such risks as are generally deemed adequate and customary for their
businesses including, but not limited to, policies covering real and personal
property owned or leased by the Company and its subsidiaries against theft,
damage, destruction and acts of vandalism. The Company has no reason to believe
that it or any subsidiary will not be able (i) to renew its existing insurance
coverage as and when such policies expire or (ii) to obtain comparable coverage
from similar institutions as may be necessary or appropriate to conduct its
business as now conducted and at a cost that would not result in a Material
Adverse Change. Neither the Company nor any subsidiary has been denied any
insurance coverage which it has sought or for which it has applied.

            3.15 Disclosure. No representation or warranty by the Company in
this Agreement or in any Annex hereto, or in any list, statement, document or
information set forth in or attached to any Schedule delivered or to be
delivered pursuant hereto, contains or will contain any untrue statement of a
material fact or omits or will omit any material fact necessary in order to make
the statements contained therein, in light of the circumstances in which they
were made, not misleading.

      4. Representations of the Purchaser. The Purchaser represents and warrants
to the Company as follows:

            4.1 Investment. The Purchaser is acquiring the Shares for its own
account for investment and not with a view to, or for sale in connection with,
any distribution thereof, nor with any present intention of distributing or
selling the same; and, except as contemplated by this Agreement and the
Registration Rights Agreement hereto, the Purchaser has no present or
contemplated agreement, undertaking, arrangement, obligation, indebtedness or
commitment providing for the disposition thereof. The Purchaser is an
"accredited investor" as defined in Rule 501(a) under the Securities Act of
1933, as amended (the "Securities Act").


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<PAGE>

            4.2 Authority. The Purchaser has full power and authority to enter
into and to perform this Agreement in accordance with its terms. The Purchaser
has not been organized, reorganized or recapitalized specifically for the
purpose of investing in the Company.

            4.3 Experience. The Purchaser has carefully reviewed the
representations concerning the Company contained in this Agreement, has made
detailed inquiry concerning the Company, its business and its personnel and has
received and reviewed the Company Reports; the officers of the Company have made
available to the Purchaser any and all written information which it has
requested and have answered to the Purchaser's satisfaction all inquiries made
by the Purchaser; and the Purchaser has sufficient knowledge and experience in
finance and business that it is capable of evaluating the risks and merits of
its investment in the Company and the Purchaser is able financially to bear the
risks thereof.

      5. Conditions to the Obligations of the Purchaser. The obligation of the
Purchaser to purchase the Shares at the Closing is subject to the fulfillment,
or the waiver by the Purchaser, of each of the following conditions on or before
the Closing:

            5.1 Accuracy of Representations and Warranties. Each representation
and warranty contained in Section 3 of this Agreement shall be true on and as of
the Closing Date with the same effect as though such representation and warranty
had been made on and as of that date.

            5.2 Performance. The Company shall have performed and complied with
all agreements and conditions contained in this Agreement required to be
performed or complied with by the Company prior to or at the Closing. 5.3
Opinion of Counsel. The Purchaser shall have received an opinion from Hale and
Dorr LLP, special counsel for the Company, dated the Closing Date, addressed to
the Purchaser, to the effect set forth on Annex B appended hereto.

            5.4 Registration Rights Agreement. The Registration Rights Agreement
shall have been executed and delivered by the Company.

            5.5 Certificates and Documents. The Company shall have delivered to
special counsel to the Purchaser:

                  (a) The Restated Articles of Organization of the Company, as
amended and in effect as of the Closing Date, certified by the Secretary of the
Commonwealth of the Commonwealth of Massachusetts;

                  (b) A certificate, as of the most recent practicable date, as
to the corporate good standing of the Company issued by the Secretary of the
Commonwealth of the Commonwealth of Massachusetts;

                  (c) The Amended and Restated By-laws of the Company, as in
effect as of the Closing Date, certified by the Clerk of the Company as of the
Closing Date; and


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                  (d) Votes of the Board of Directors of the Company,
authorizing and approving all matters in connection with this Agreement and the
transactions contemplated hereby, certified by the Clerk or Assistant Clerk of
the Company as of the Closing Date.

                  (e) Compliance Certificate. The Company shall have delivered
to the Purchaser a certificate, executed by the President of the Company, dated
the Closing Date, certifying to the fulfillment of the conditions specified in
Sections 5.1 and 5.2 of this Agreement.

      6. Condition to the Obligations of the Company. The obligations of the
Company under this Agreement are subject to fulfillment, or the waiver, of the
following condition on or before the Closing:

            6.1 Accuracy of Representations and Warranties. The representations
and warranties of the Purchaser contained in Section 4 of this Agreement shall
be true on and as of the Closing Date with the same effect as though such
representations and warranties had been made on and as of that date.

      7. Transfer of Shares.

            7.1 Restricted Shares. "Restricted Shares" means (i) the Shares and
(ii) any other securities of the Company issued in respect of such shares (as a
result of stock splits, stock dividends, reclassifications, recapitalizations,
or similar events); provided, that, shares of Common Stock which are Restricted
Shares shall cease to be Restricted Shares (x) upon any sale pursuant to a
registration statement under the Securities Act or Rule 144 under the Securities
Act or (y) at such time as they become eligible for sale under Rule 144(k) under
the Securities Act.

            7.2 Requirements for Transfer.

                  (a) Restricted Shares shall not be sold or transferred unless
either (i) they first shall have been registered under the Securities Act, or
(ii) the Company first shall have been furnished with an opinion of legal
counsel, reasonably satisfactory to the Company, to the effect that such sale or
transfer is exempt from the registration requirements of the Securities Act.

                  (b) Notwithstanding the foregoing, no registration or opinion
of counsel shall be required for transfer by the Purchaser to a wholly owned
subsidiary of the Purchaser; provided, that, the transferee in each case agrees
in writing to be subject to the terms of this Section 7 to the same extent as if
it were the Purchaser.

            7.3 Legend. Each certificate representing Restricted Shares shall
bear a legend substantially in the following form:

            "The shares represented by this certificate have not been
            registered under the Securities Act of 1933, as amended, and
            may not be offered, sold or otherwise transferred, pledged or
            hypothecated unless and until such shares are registered under
            such Act or an opinion of counsel satisfactory to the Company
            is obtained to the effect that such registration is not
            required."


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      8. Other Agreements.

            8.1 Board of Directors. The Company hereby covenants to the
Purchaser that until the first to occur of (i) March 31, 2002 and (ii) such time
as the Purchaser no longer owns in excess of 20% of the outstanding shares of
Common Stock, the Company shall, unless it receives the prior written consent of
the Purchaser to act otherwise, use its best efforts to cause (I) two
individuals designated by the Purchaser in writing to the Company to be
nominated and elected as members of the Company's Board of Directors and (II)
the number of members of the Company's Board of Directors to be not in excess of
six; provided, that, if the Purchaser redesignates the individuals to be
nominated and elected pursuant to this Section 8.1, the Company need not use
such best efforts until such time as the Company has received the effective
written resignations from the Company's Board of Directors of the directors
previously designated by the Purchaser pursuant to this Section 8.1; provided,
further, that the Company hereby covenants to the Purchaser that until the first
occur of (x) March 31, 2002 and (y) such time as the Purchaser no longer owns in
excess of 20% of the outstanding shares of Common Stock, the Company shall use
its best efforts to cause any vacancy on the Company's Board of Directors caused
by death, resignation or removal of a director designated by the Purchaser to be
filled by an individual designated by the Purchaser.

            8.2 Confidentiality. The Purchaser agrees that it will keep
confidential and will not disclose or divulge any confidential proprietary or
secret information which the Purchaser may obtain or have obtained from the
Company from materials submitted by the Company to the Purchaser pursuant to or
in connection with this Agreement, unless such information is known, or until
such information becomes known, to the public (other than as a result of a
breach of this Section 8.2 by the Purchaser); provided, that, the Purchaser may
disclose such information to its attorneys, accountants, consultants and other
professionals to the extent necessary to obtain services in connection with its
investment in the Company.

            8.3 Expenses. The Purchaser shall pay, at the Closing, the
reasonable fees (up to a maximum of $15,000) and disbursements of Hale and Dorr
LLP, counsel to the Company, in connection with the preparation of this
Agreement and the other agreements contemplated hereby and the closing of the
transactions contemplated hereby.

            8.4 Brokers. Each of the Company and the Purchaser (i) represents
and warrants to the other Party that it has not retained a finder or broker in
connection with the transactions contemplated by this Agreement, and (ii) will
indemnify and save the other Party harmless from and against any and all claims,
liabilities or obligations with respect to brokerage or finders' fees or
commissions, or consulting fees in connection with the transactions contemplated
by this Agreement asserted by any person on the basis of any statement or
representation alleged to have been made by such indemnifying Party.

      9. Miscellaneous.

            9.1 Successors and Assigns. This Agreement shall be binding upon and
inure to the benefit of the Parties and their respective successors and
permitted assigns; provided, that, neither Party may assign their respective
rights and obligations without the prior written consent of the other Party and;
provided, further, that with respect to the Purchaser's rights under Section


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8.1 of this Agreement, (i) a merger or consolidation in which the Purchaser is a
constituent corporation and the stockholders of the Purchaser prior to such
transaction do not represent a majority voting interest in the surviving entity
and (ii) a sale of all or substantially all of the assets of the Purchaser,
shall both be deemed an assignment by the Purchaser requiring the prior written
consent of the Company under this Section 9.1. Any assignment in contravention
of this Section 9.1 shall be void.

            9.2 Survival. All representations and warranties made by the Parties
in this Agreement shall speak as of the Closing Date and shall survive the
Closing. The representations and warranties set forth in Section 3 of this
Agreement shall expire on the first anniversary of the Closing Date, except for
claims, if any, asserted in writing prior to such first anniversary, which shall
survive until finally resolved and satisfied in full.

            9.3 Severability. The invalidity or unenforceability of any
provision of this Agreement shall not affect the validity or enforceability of
any other provision of this Agreement.

            9.4 Governing Law. This Agreement shall be governed by and construed
in accordance with the internal laws of the Commonwealth of Massachusetts
(without reference to the conflicts of law provisions thereof).

            9.5 Notices. All notices, requests, consents, and other
communications under this Agreement shall be in writing and shall be deemed
delivered (i) two business days after being sent by registered or certified
mail, return receipt requested, postage prepaid or (ii) one business day after
being sent via a reputable nationwide overnight courier service guaranteeing
next business day delivery (unless the courier's receipt evidences a later
date), in each case to the intended recipient as set forth below:


To the Company:                                  Copy to:

Peritus Software Services, Inc.
Suite 111                                        Hale and Dorr LLP
112 Turnpike Road                                60 State Street
Westborough, Massachusetts  01581                Boston, Massachusetts  02109
Attention:  President                            Attention:  Peter B. Tarr, Esq.

To the Purchaser:                                Copy to:

Rocket Software, Inc.                            Lucash, Gesmer & Updegrove, LLP
Two Apple Hill Drive                             40 Broad Street
Natick, Massachusetts  01760                     Boston, Massachusetts  02109
Attention:  Johan Magnusson                      Attention:  Jill Swaim, Esq.

      Any Party may give any notice, request, consent or other communication
under this Agreement using any other means (including, without limitation,
personal delivery, messenger service, telecopy, first class mail or electronic
mail), but no such notice, request, consent or other


                                      -9-
<PAGE>

communication shall be deemed to have been duly given unless and until it is
actually received by the party for whom it is intended. Any Party may change the
address to which notices, requests, consents or other communications hereunder
are to be delivered by giving the other Party notice in the manner set forth in
this Section 9.5.

            9.6 Complete Agreement. This Agreement, the Disclosure Schedule and
the Registration Rights Agreement constitute the entire agreement and
understanding of the Parties with respect to the subject matter hereof and
supersede all prior agreements and understandings relating to such subject
matter.

            9.7 Amendments and Waivers. Except as otherwise expressly set forth
in this Agreement, any term of this Agreement may be amended or terminated and
the observance of any term of this Agreement may be waived (either generally or
in a particular instance and either retroactively or prospectively), with the
written consent of the Company and the Purchaser. No waivers of or exceptions to
any term, condition or provision of this Agreement, in any one or more
instances, shall be deemed to be, or construed as, a further or continuing
waiver of any such term, condition or provision.

            9.8 Counterparts; Facsimile Signatures. This Agreement may be
executed in any number of counterparts, each of which shall be deemed to be an
original, and all of which shall constitute one and the same document. This
Agreement may be executed by facsimile signatures.

            9.9 Section Headings. The section headings are for the convenience
of the Parties and in no way alter, modify, amend, limit, or restrict the
contractual obligations of the Parties.

                                    * * * * *


                                      -10-
<PAGE>

      Executed as of the date first written above.

                                      COMPANY:

                                      PERITUS SOFTWARE SERVICES, INC.


                                      By:_________________________________
                                          Name:  John Giordano
                                          Title: President and
                                                 Chief Executive Officer

                                      PURCHASER:

                                      ROCKET SOFTWARE, INC.


                                      By:_________________________________
                                          Name:
                                          Title:


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