<PAGE>

                                                                   EXHIBIT 10.15

     THESE SECURITIES HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933
     AS AMENDED, OR ANY STATE SECURITIES LAWS. THEY MAY NOT BE SOLD, OFFERED FOR
     SALE, PLEDGED, OR HYPOTHECATED IN THE ABSENCE OF AN EFFECTIVE REGISTRATION
     STATEMENT RELATED THERETO OR AN OPINION OF COUNSEL (WHICH MAY BE COMPANY
     COUNSEL) REASONABLY SATISFACTORY TO THE COMPANY THAT SUCH REGISTRATION IS
     NOT REQUIRED UNDER THE SECURITIES ACT OF 1933 OR ANY APPLICABLE STATE
     SECURITIES LAWS.

                               WARRANT AGREEMENT

                   To Purchase Shares of the Common Stock of

                             XACTDATA SERVICES, INC.

              Dated as of September 1, 1995 (the "Effective Date")


     WHEREAS, XactData Services, Inc., a Washington corporation (the "Company")
has entered into a Master Lease Agreement dated as of September 1, 1995,
Equipment Schedule No. VL-1 dated as of September 1, 1995, and related Summary
Equipment Schedules (collectively, the "Leases") with Comdisco, Inc., a Delaware
corporation (the "Warrantholder"); and

     WHEREAS, the Company desires to grant to Warrantholder, in consideration
for such Leases, the right to purchase shares of its Common Stock;

     NOW, THEREFORE, in consideration of the Warrantholder executing and
delivering such Leases and in consideration of mutual covenants and agreements
contained herein, the Company and Warrantholder agree as follows:

1.  GRANT OF THE RIGHT TO PURCHASE COMMON STOCK.
    -------------------------------------------

    The Company hereby grants to the Warrantholder, and the Warrantholder is
entitled, upon the terms and subject to the conditions hereinafter set forth, to
subscribe to and purchase, from the Company, 433 fully paid and non-assessable
shares of the Company's Common Stock ("Common Stock") at a purchase price of
$72.00 per share (the "Exercise Price"). The number and purchase price of such
shares are subject to adjustment as provided in Section 8 hereof.

2.  TERM OF THE WARRANT AGREEMENT.
    -----------------------------

    Except as otherwise provided for herein, the term of this Warrant Agreement
and the right to purchase Common Stock as granted herein shall commence on the
Effective Date and shall be exercisable for a period of (i) ten (10) years or
(ii) five (5) years from the effective date of the Company's initial public
offering, whichever is longer.

3.  EXERCISE OF THE PURCHASE  RIGHTS.
    --------------------------------

    The purchase rights set forth in this Warrant Agreement are exercisable by
the Warrantholder, in whole or in part, at any time, or from time to time, prior
to the expiration of the term set forth in Section 2 above, by tendering to the
Company at its principal office a notice of exercise in the form attached hereto
as Exhibit I (the "Notice of Exercise"), duly completed and executed. Promptly
upon receipt of the Notice of Exercise and the payment of the purchase price in
accordance with the terms set forth below, and in no event later than twenty-one
(21) days thereafter, the Company shall issue to the Warrantholder a certificate
for the number of shares of Common Stock purchased and shall execute the
acknowledgment of exercise in the form attached hereto as Exhibit II (the
"Acknowledgment of Exercise") indicating the number of shares which remain
subject to future purchases, if any.

    The Exercise Price may be paid at the Warrantholder's election either (i)
by cash or check, or (ii) by surrender of Warrants ("Net Issuance") as
determined below. If the Warrantholder elects the Net Issuance method, the
Company will issue Common Stock in accordance with the following formula:

          X = Y(A-B)
              ------
                A



                                      -1-
<PAGE>

                A

Where: X =  the number of shares of Common Stock to be issued to the
             Warrantholder.

             Y =   the number of shares of Common Stock requested to be
                   exercised under this Warrant Agreement.

             A =   the fair market value of one (1) share of Common Stock.

             B =   the Exercise Price.

     For purposes of the above calculation, current fair market value of Common
Stock shall mean with respect to each share of Common Stock:

     (i)  if the exercise is in connection with an initial public offering of
     the Company's Stock, and if the Company's Registration Statement relating
     to such public offering has been declared effective by the SEC, then the
     fair market value per share shall be the initial "Price to Public"
     specified in the final prospectus with respect to the offering, and:

     (ii)  if this Warrant is exercised after, and not in connection with the
     Company's initial public offering, and:

          (a)  if traded on a securities exchange, the fair market value shall
          be deemed to be the average of the closing prices over a twenty-one
          (21) day period ending three days before the day the current fair
          market value of the securities is being determined, or

          (b)  if actively traded over-the-counter, the fair market value shall
          be deemed to be the average of the closing bid and asked prices quoted
          on the NASDAQ system (or similar system) over the twenty-one (21) day
          period ending three days before the day the current fair market value
          of the securities is being determined.

     (iii)  if at any time the Common Stock is not listed on any securities
     exchange or quoted in the NASDAQ System or the over-the-counter market,
     the current fair market value of Common Stock shall be the highest price
     per share which the Company could obtain from a willing buyer (not a
     current employee or director) for shares of Common Stock sold by the
     Company, from authorized but unissued shares, as determined in good faith
     by its Board of Directors, unless the Company shall become subject to a
     merger, acquisition or other consolidation pursuant to which the Company is
     not the surviving party, in which case the fair market value of Common
     Stock shall be deemed to be the value received by the holders of the
     Company's Common Stock pursuant to such merger or acquisition.

     Upon partial exercise by either cash or Net Issuance, the Company shall
promptly issue an amended Warrant Agreement representing the remaining number of
shares purchasable hereunder. All other terms and conditions of such amended
Warrant Agreement shall be identical to those contained herein, including, but
not limited to the Effective Date hereof.

4.  RESERVATION OF SHARES.
    ---------------------

     (a)  Authorization and Reservation of Shares. During the term of this
          ---------------------------------------
Warrant Agreement, the Company will at all times have authorized and reserved a
sufficient number of shares of its Common Stock to provide for the exercise of
the rights to purchase Common Stock as provided for herein.

     (b) Registration or Listing. If any shares of Common Stock required to be
         -----------------------
reserved hereunder require registration with or approval of any governmental
authority under any Federal or State law (other than any registration under the
1933 Act, as then in effect, or any similar Federal statute then enforced, or
any state securities law, required by reason of any transfer involved in such
conversion), or listing on any domestic securities exchange, before such shares
may be issued, the Company will, at its expense and as expeditiously as
possible, use its best efforts to cause such shares to be duly registered,
listed or approved for listing on such domestic securities exchange, as the case
may be.

                                     - 2 -
<PAGE>

5.   NO FRACTIONAL SHARES OR SCRIP.
     -----------------------------

     No fractional shares or scrip representing fractional shares shall be
issued upon the exercise of the Warrant, but in lieu of such fractional shares
the Company shall make a cash payment therefor upon the basis of the Exercise
Price then in effect.

6.   NO RIGHTS AS SHAREHOLDER.
     ------------------------

     This Warrant Agreement does not entitle the Warrantholder to any voting
rights or other rights as a shareholder of the Company prior to the exercise of
the Warrant.

7.   WARRANTHOLDER REGISTRY.
     ----------------------

     The Company shall maintain a registry showing the name and address of the
registered holder of this Warrant Agreement.

8.   ADJUSTMENT RIGHTS.
     -----------------

     The purchase price per share and the number of shares of Common Stock
purchasable hereunder are subject to adjustment, as follows:

     (a)  Merger and Sale of Assets. If at any time there shall be a capital
          -------------------------
reorganization of the shares of the Company's stock (other than a combination,
reclassification, exchange or subdivision of shares otherwise provided for
herein), or a merger or consolidation of the Company with or into another
corporation when the Company is not the surviving corporation, or the sale of
all or substantially all of the Company's properties and assets to any other
person (hereinafter referred to as a "Merger Event"), then, as a part of such
Merger Event, lawful provision shall be made so that the Warrantholder shall
thereafter be entitled to receive, upon exercise of the Warrant, the number of
shares of Common Stock or other securities of the successor corporation
resulting from such Merger Event, equivalent in value to that which would have
been issuable if Warrantholder had exercised this Warrant immediately prior to
the Merger Event. In any such case, appropriate adjustment (as determined in
good faith by the Company's Board of Directors) shall be made in the application
of the provisions of this Warrant Agreement with respect to the rights and
interest of the Warrantholder after the Merger Event to the end that the
provisions of this Warrant Agreement (including adjustments of the Exercise
Price and number of shares of Common Stock purchasable) shall be applicable to
the greatest extent possible.

     (b)  Reclassification of Shares. If the Company at any time shall, by
          --------------------------
combination, reclassification, exchange or subdivision of securities or
otherwise, change any of the securities as to which purchase rights under this
Warrant Agreement exist into the same or a different number of securities of any
other class or classes, this Warrant Agreement shall thereafter represent the
right to acquire such number and kind of securities as would have been issuable
as the result of such change with respect to the securities which were subject
to the purchase rights under this warrant Agreement immediately prior to such
combination, reclassification, exchange, subdivision or other change.

     (c)  Subdivision or Combination of Shares. If the Company at any time shall
          ------------------------------------
combine or subdivide its Common Stock, the Exercise Price shall be
proportionately decreased in the case of a subdivision, or proportionately
increased in the case of a combination.

     (d)  Stock Dividends. If the Company at any time shall pay a dividend
          ---------------
payable in, or make any other distribution (except any distribution specifically
provided for in the foregoing subsections (a) or (b)) of the Company's stock,
then the Exercise Price shall be adjusted, from and after the record date of
such dividend or distribution, to that price determined by multiplying the
Exercise Price in effect immediately prior to such record date by a fraction (i)
the numerator of which shall be the total number of all shares of the Company's
stock outstanding immediately prior to such dividend or distribution, and (ii)
the denominator of which shall be the total number of all shares of the
Company's stock outstanding immediately after such dividend or distribution. The
Warrantholder shall thereafter be entitled to purchase, at the Exercise Price
resulting from such adjustment, the number of shares of Common Stock (calculated
to the nearest whole share) obtained by multiplying the Exercise Price in effect
immediately prior to such adjustment by the number of

                                     - 3 -
<PAGE>

shares of Common Stock issuable upon the exercise hereof immediately prior to
such adjustment and dividing the product thereof by the Exercise Price resulting
from such adjustment.

     (e)  Right to Purchase Additional Stock. If, the Warrantholder's total cost
          ----------------------------------
of equipment leased pursuant to the Leases exceeds $260,000, Warrantholder shall
have the right to purchase from the Company, at the Exercise Price (adjusted as
set forth herein), an additional number of shares, which number shall be
determined by (i) multiplying the amount by which the Warrantholder's total
equipment cost exceeds $260,000 by 12%, and (ii) dividing the product thereof by
the Exercise Price per share referenced above.

     (f)   Antidilution Rights. Additional antidilution rights applicable to the
           -------------------
Common Stock purchasable hereunder are as set forth in the Company's Certificate
of Incorporation, as amended through the Effective Date, a true and complete
copy of which is attached hereto as Exhibit     (the "Charter"). The Company
shall promptly provide the Warrantholder with any restatement, amendment,
modification or waiver of the Charter. The Company shall provide Warrantholder
with prior written notice of any issuance of its stock or other equity security
to occur after the Effective Date of this Warrant, which notice shall include
(a) the price at which such stock or security is to be sold, (b) the number of
shares to be issued, and (c) such other information as necessary for
Warrantholder to determine if a dilutive event has occurred.

     (g)  Notice of Adjustments. If: (i) the Company shall declare any dividend
          ---------------------
or distribution upon its stock, whether in cash, property, stock or other
securities; (ii) the Company shall offer for subscription prorata to the holders
of any class of its Preferred or other convertible stock any additional shares
of stock of any class or other rights; (iii) there shall be any Merger Event;
(iv) there shall be an initial public offering; or (v) there shall be any
voluntary or involuntary dissolution, liquidation or winding up of the Company;
then, in connection with each such event, the Company shall send to the
Warrantholder: (A) at least twenty (20) days' prior written notice of the date
on which the books of the Company shall close or a record shall be taken for
such dividend, distribution, subscription rights (specifying the date on which
the holders of Common Stock shall be entitled thereto) or for determining rights
to vote in respect of such Merger Event, dissolution, liquidation or winding
up; (B) in the case of any such Merger Event, dissolution, liquidation or
winding up, at least twenty (20) days' prior written notice of the date when the
same shall take place (and specifying the date on which the holders of Common
Stock shall be entitled to exchange their Common Stock for securities or other
property deliverable upon such Merger Event, dissolution, liquidation or winding
up); and (C) in the case of a public offering, the Company shall give the
Warrantholder at least twenty (20) days written notice prior to the effective
date hereof.

     Each such written notice shall set forth, in reasonable detail, (i) the
event requiring the adjustment, (ii) the amount of the adjustment, (iii) the
method by which such adjustment was calculated, (iv) the Exercise Price, and (v)
the number of shares subject to purchase hereunder after giving effect to such
adjustment, and shall be given by first class mail, postage prepaid, addressed
to the Warrantholder, at the address as shown on the books of the Company.

     (g)  Timely Notice. Failure to timely provide such notice required by
          -------------
subsection (g) above shall entitle Warrantholder to retain the benefit of the
applicable notice period notwithstanding anything to the contrary contained in
any insufficient notice received by Warrantholder. The notice period shall begin
on the date Warrantholder actually receives a written notice containing all the
information specified above.

9.   REPRESENTATIONS, WARRANTIES AND COVENANTS OF THE COMPANY.
     --------------------------------------------------------

     (a)  Reservation of Common Stock.  The Common Stock issuable upon exercise
          ---------------------------
of the Warrantholder's rights has been duly and validly reserved and, when
issued in accordance with the provisions of this Warrant Agreement, will be
validly issued, fully paid and non-assessable, and will be free of any taxes,
liens, charges or encumbrances of any nature whatsoever; provided, however, that
the Common Stock issuable pursuant to this Warrant Agreement may be subject to
restrictions on transfer under state and/or Federal securities laws. The Company
has made available to the Warrantholder true, correct and complete copies of
its Charter and Bylaws, as amended, and minutes of all Board of Directors
(including all committees of the Board of Directors, if any) and Shareholder
meetings from___, 19__ through

                                     - 4 -
<PAGE>

_____, 19__ .  The issuance of certificates for shares of Common Stock upon
exercise of the Warrant Agreement shall be made without charge to the
Warrantholder for any issuance tax in respect thereof, or other cost incurred by
the Company in connection with such exercise and the related issuance of shares
of Common Stock. The Company shall not be required to pay any tax which may be
payable in respect of any transfer involved and the issuance and delivery of any
certificate in a name other than that of the Warrantholder.

     (b)  Due Authority. The execution and delivery by the Company of this
          -------------
Warrant Agreement and the performance of all obligations of the Company
hereunder, including the issuance to Warrantholder of the right to acquire the
shares of Common Stock, have been duly authorized by all necessary corporate
action on the part of the Company, and the Leases and this Warrant Agreement are
not inconsistent with the Company's Charter or Bylaws, do not contravene any law
or governmental rule, regulation or order applicable to it, do not and will not
contravene any provision of, or constitute a default under, any indenture,
mortgage, contract or other instrument to which it is a party or by which it is
bound, and the Leases and this Warrant Agreement constitute legal, valid and
binding agreements of the Company, enforceable in accordance with their
respective terms.

     (c)  Consents and Approvals. No consent or approval of, giving of notice
          ----------------------
to, registration with, or taking of any other action in respect of any state,
Federal or other governmental authority or agency is required with respect to
the execution, delivery and performance by the Company of its obligations under
this Warrant Agreement, except for the filing of notices pursuant to Regulation
D under the 1933 Act and any filing required by applicable state securities law,
which filings will be effective by the time required thereby.

     (d)  Issued Securities. All issued and outstanding shares of Common Stock,
          -----------------
Preferred Stock or any other securities of the Company have been duly authorized
and validly issued and are fully paid and nonassessable. All outstanding shares
of Common Stock, Preferred Stock and any other securities were issued in full
compliance with all Federal and state securities laws. In addition:

     (i) The authorized capital of the Company consists of (A) 2,000,000 shares
of Common Stock, of which 67,951 shares are issued and outstanding.

     (ii)  There are no other options, warrants, conversion privileges or other
rights presently outstanding to purchase or otherwise acquire any authorized but
unissued shares of the Company's capital stock or other securities of the
Company except as outline in Exhibit_____.

     (iii)  In accordance with the Company's Articles of Incorporation, no
shareholder of the Company has preemptive rights to purchase new issuances of
the Company's capital stock.

     (e) Insurance. The Company has in full force and effect insurance policies,
         ---------
with extended coverage, insuring the Company and its property and business
against such losses and risks, and in such amounts, as are customary for
corporations engaged in a similar business and similarly situated and as
otherwise may be required pursuant to the terms of any other contract or
agreement.

     (f)  Other Commitments to Register Securities. Except as set forth in this
          ----------------------------------------
Warrant Agreement, the Company is not, pursuant to the terms of any other
agreement currently in existence, under any obligation to register under the
1933 Act any of its presently outstanding securities or any of its securities
which may hereafter be issued.

     (g)  Exempt Transaction. Subject to the accuracy of the Warrantholder's
          ------------------
representations in Section 10 hereof, the issuance of the Common Stock upon
exercise of this Warrant will constitute a transaction exempt from (i) the
registration requirements of Section 5 of the 1933 Act, in reliance upon Section
4(2) thereof, and (ii) the qualification requirements of the applicable state
securities laws.

     (h)  Compliance with Rule 144. At the written request of the Warrantholder,
          ------------------------
who proposes to sell Common Stock issuable upon the exercise of the Warrant in
compliance with Rule 144 promulgated by the Securities and Exchange Commission,
the Company shall furnish to the Warrantholder, within ten days after receipt of
such request, a written statement confirming the Company's compliance with the
filing requirements of the Securities and Exchange Commission as set forth in
such Rule, as such Rule may be amended from time to time.

                                     - 5 -
<PAGE>

10. REPRESENTATIONS AND COVENANTS OF THE WARRANTHOLDER.
    --------------------------------------------------

     This Warrant Agreement has been entered into by the Company in reliance
upon the following representations and covenants of the Warrantholder:

     (a) Investment Purpose. The right to acquire Common Stock issuable upon
         ------------------
exercise of the Warrantholder's rights contained herein will be acquired for
investment and not with a view to the sale or distribution of any part thereof,
and the Warrantholder has no present intention of selling or engaging in any
public distribution of the same except pursuant to a registration or exemption.

     (b)  Private Issue. The Warrantholder understands (i) that the Common Stock
          -------------
issuable upon exercise of this Warrant is not registered under the 1933 Act or
qualified under applicable state securities laws on the ground that the issuance
contemplated by this Warrant Agreement will be exempt from the registration and
qualifications requirements thereof, and (ii) that the Company's reliance on
such exemption is predicated on the representations set forth in this Section
10.

     (c)  Disposition of Warrantholder's Rights. In no event will the
          -------------------------------------
Warrantholder make a disposition of any of its rights to acquire Common Stock
unless and until (i) it shall have notified the Company of the proposed
disposition, and (ii) if requested by the Company, it shall have furnished the
Company with an opinion of counsel (which counsel may either be inside or
outside counsel to the Warrantholder) satisfactory to the Company and its
counsel to the effect that (A) appropriate  action necessary for compliance with
the 1933 Act has been taken, or (B) an exemption from the registration
requirements of the 1933 Act is available.  Notwithstanding the foregoing, the
restrictions imposed upon the transferability of any of its rights to acquire
Common Stock or do not apply to transfers from the beneficial owner of any of
the aforementioned securities to its nominee or from such nominee to its
beneficial owner, and shall terminate as to any particular share of Common Stock
when (1) such security shall have been effectively registered under the 1933 Act
and sold by the holder thereof in accordance with such registration or (2) such
security shall have been sold without registration in compliance with Rule 144
under the 1933 Act, or (3) a letter shall have been issued to the Warrantholder
at its request by the staff of the Securities and Exchange Commission or a
ruling shall have been issued to the Warrantholder at its request by such
Commission stating that no action shall be recommended by such staff or taken by
such Commission, as the case may be, if such security is transferred without
registration under the 1933 Act in accordance with the conditions set forth in
such letter or ruling and such letter or ruling specifies that no subsequent
restrictions on transfer are required.  Whenever the restrictions imposed
hereunder shall terminate, as hereinabove provided, the Warrantholder or holder
of a share of Common Stock then outstanding as to which such restrictions have
terminated shall be entitled to receive from the Company, without expense to
such holder, one or more new certificates for the Warrant or for such shares of
Common Stock not bearing any restrictive legend.

     (d)  Financial Risk. The Warrantholder has such knowledge and experience in
          --------------
financial and business matters as to be capable of evaluating the merits and
risks of its investment, and has the ability to bear the economic risks of its
investment.

     (e)  Risk of No Registration. The Warrantholder understands that if the
          -----------------------
Company does not register with the Securities and Exchange Commission pursuant
to Section 12 of the 1933 Act, or file reports pursuant to Section 15(d), of the
Securities Exchange Act of 1934 (the "1934 Act"), or if a registration statement
covering the securities under the 1933 Act is not in effect when it desires to
sell (i) the rights to purchase Common Stock pursuant to this Warrant Agreement,
or (ii) the Common Stock issuable upon exercise of the right to purchase, it may
be required to hold such securities for an indefinite period. The Warrantholder
also understands that any sale of its rights of the Warrantholder to purchase
Common Stock or Common Stock which might be made by it in reliance upon Rule 144
under the 1933 Act may be made only in accordance with the terms and conditions
of that Rule.

     (f)  Accredited Investor. Warrantholder is an "accredited investor" within
          -------------------
the meaning of the Securities and Exchange Rule 501 of Regulation D, as
presently in effect.

11.   TRANSFERS. Subject to the terms and conditions contained in Section 10
      ---------
hereof, this Warrant Agreement and all rights hereunder are transferable in
whole or

                                     - 6 -
<PAGE>

event shall the number of transfers of the rights and interests in all of the
Warrants exceed three (3) transfers. The transfer shall be recorded on the books
of the Company upon receipt by the Company of a notice of transfer in the form
attached hereto as Exhibit III (the "Transfer Notice"), at its principal offices
and the payment to the Company of all transfer taxes and other governmental
charges imposed on such transfer.

12.   MISCELLANEOUS.
      -------------

     (a) Effective Date. The provisions of this Warrant Agreement shall be
         --------------
construed and shall be given effect in all respects as if it had been executed
and delivered by the Company on the date hereof. This Warrant Agreement shall be
binding upon any successors or assigns of the Company.

     (b)  Attorney's Fees. In any litigation, arbitration or court proceeding
          ---------------
between the Company and the Warrantholder relating hereto, the prevailing party
shall be entitled to attorneys' fees and expenses and all costs of proceedings
incurred in enforcing this Warrant Agreement.

     (c)  Governing Law. This Warrant Agreement shall be governed by and
          -------------
construed for all purposes under and in accordance with the laws of the State of
Illinois.

     (d)  Counterparts. This Warrant Agreement may be executed in two or more
          ------------
counterparts, each of which shall be deemed an original, but all of which
together shall constitute one and the same instrument.

     (e)  Notices. Any notice required or permitted hereunder shall be given in
          -------
writing and shall be deemed effectively given upon personal delivery, facsimile
transmission (provided that the original is sent by personal delivery or mail as
hereinafter set forth) or seven (7) days after deposit in the United States
mail, by registered or certified mail, addressed (i) to the Warrantholder at
6111 North River Road, Rosemont, Illinois 60018, attention: James Labe, Venture
Group, cc: Legal Department, attn: General Counsel, (and/or, if by facsimile,
(708) 518-5466 and (708)518-5088) and (ii) to the Company at 600 University St.,
#911, Seattle, WA  98101 attention: (and/or if by facsimile, (206) 382-6615 or
at such other address as any such party may subsequently designate by written
notice to the other party.

     (f)  Remedies. In the event of any default hereunder, the non-defaulting
          --------
party may proceed to protect and enforce its rights either by suit in equity
and/or by action at law, including but not limited to an action for damages as a
result of any such default, and/or an action for specific performance for any
default where Warrantholder will not have an adequate remedy at law and where
damages will not be readily ascertainable. The Company expressly agrees that it
shall not oppose an application by the Warrantholder or any other person
entitled to the benefit of this Agreement requiring specific performance of any
or all provisions hereof or enjoining the Company from continuing to commit any
such breach of this Agreement.

     (g)  No Impairment of Rights. The Company will not, by amendment of its
          -----------------------
Charter or through any other means, avoid or seek to avoid the observance or
performance of any of the terms of this Warrant, but will at all times in good
faith assist in the carrying out of all such terms and in the taking of all such
actions as may be necessary or appropriate in order to protect the rights of the
Warrantholder against impairment.

     (h)  Survival. The representations, warranties, covenants and conditions of
          --------
the respective parties contained herein or made pursuant to this Warrant
Agreement shall survive the execution and delivery of this Warrant Agreement.

     (i)  Severability. In the event any one or more of the provisions of this
          ------------
Warrant Agreement shall for any reason be held invalid, illegal or
unenforceable, the remaining provisions of this Warrant Agreement shall be
unimpaired, and the invalid, illegal or unenforceable provision shall be
replaced by a mutually acceptable valid, legal and enforceable provision, which
comes closest to the intention of the parties underlying the invalid, illegal or
unenforceable provision.

     (j) Amendments.  Any provision of this Warrant Agreement may be amended by
         ----------
a written instrument signed by the Company and by the Warrantholder.

                                      -7-
<PAGE>

     (k)  Additional Documents. The Company, upon execution of this Warrant
          --------------------
Agreement, shall provide the Warrantholder with certified resolutions with
respect to the representations, warranties and covenants set forth in
subparagraphs (a) through (d), (f) and (g) of Section 9 above. If the purchase
price for the Leases referenced in the preamble of this Warrant Agreement
exceeds $1,000,000, the Company will also provide Warrantholder with an opinion
from the Company's counsel with respect to those same representations,
warranties and covenants. The Company shall also supply such other documents as
the Warrantholder may from time to time reasonably request.

     IN WITNESS WHEREOF, the parties hereto have caused this Warrant Agreement
to be executed by its officers thereunto duly authorized as of the Effective
Date.

                         Company: XACTDATA SERVICES, INC.

                         By:    /s/ [illegible]
                                ------------------------
                         Title: [illegible] President
                                ------------------------
                         Warrantholder: COMDISCO, INC.

                         By:    /s/ [illegible]
                                --------------------------

                         Title: /s/ [illegible]
                                -------------------------
                                     9/19/98

                                     - 8 -
<PAGE>

                             EXHIBIT I

                          NOTICE OF EXERCISE

TO:______________________

(1)  The undersigned Warrantholder hereby elects to purchase___ shares of the
     Common Stock of XactData Services, Inc., pursuant to the terms of the
     Warrant Agreement dated the _____ day of_________________, 19__ (the
     "Warrant Agreement") between ________________________________________ and
     the Warrantholder, and tenders herewith payment of the purchase price for
     such shares in full, together with all applicable transfer taxes, if any.

(2)  In exercising its rights to purchase the Common Stock of

     ---------------------------------------------- the undersigned hereby
     confirms and acknowledges the investment representations and
     warranties made in Section 10 of the Warrant Agreement.

(3)  Please issue a certificate or certificates representing said shares of
     Common Stock in the name of the undersigned or in such other name as is
     specified below.


________________________
(Name)
________________________
(Address)

Warrantholder:   COMDISCO, INC.

By: _____________________

Title: ____________________

Date: ____________________



                                      -9-
<PAGE>

                                   EXHIBIT II

                          ACKNOWLEDGEMENT OF EXERCISE

The undersigned, ______________________________________________ hereby
acknowledge receipt of the "Notice of Exercise" from Comdisco, Inc., to purchase
____ shares of the Common Stock of XactData Services, Inc., pursuant to the
terms of the Warrant Agreement, and further acknowledges that ________ shares
remain subject to purchase under the terms of the Warrant Agreement.



                                              Company:

                                              By: ___________________________

                                              Title: __________________________

                                              Date: __________________________



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<PAGE>

                                  EXHIBIT III

                                TRANSFER NOTICE

     (To transfer or assign the foregoing Warrant Agreement execute this form
     and supply required information. Do not use this form to purchase shares.)

     FOR VALUE RECEIVED, the foregoing Warrant Agreement and all rights
evidenced thereby are hereby transferred and assigned to

________________________________________________________________________________
(Please Print)

whose address is
_____________________________________________________________________________
________________________________________________________________________________

                                    Dated: _______________________________

                                    Holder's Signature: _____________________

                                    Holder's Address: ______________________

                                    _____________________________________

Signature Guaranteed:______________________________________________

     NOTE:           The signature to this Transfer Notice must correspond with
                     the name as it appears on the face of the Warrant
                     Agreement, without alteration or enlargement or any change
                     whatever. Officers of corporations and those acting in a
                     fiduciary or other representative capacity should file
                     proper evidence of authority to assign the foregoing
                     Warrant Agreement.



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