**Exhibit 9.1****VOTING AGREEMENT**     This VOTING AGREEMENT (the “Agreement”), dated as of February 9, 2006, is made by andbetween Darwin Deason (the “Principal Stockholder”), and Affiliated Computer Services,Inc., a Delaware corporation (the “Company”).     WHEREAS, the Company is commencing as of the date hereof an issuer tender offer (the“Tender Offer”) under Rule 13e-4 of the Securities Exchange Act of 1934, as amended, forshares of its Class A Common Stock, $0.01 par value (the “Class A Shares”), on the termsspecified in the Company’s Schedule TO (as it may be amended or supplemented by the Company fromtime to time, the “Schedule TO”) filed with the Securities and Exchange Commission as ofthe date hereof;     WHEREAS, as of the date hereof, the Principal Stockholder owns, with the right to vote, thenumber of Class A Shares and the number of shares of the Company’s Class B Common Stock, $0.01 parvalue (the “Class B Shares”) set forth on Schedule A hereto (collectively, the “OwnedShares”), which represent in the aggregate, based on Company share data as of February 5, 2006,approximately 36.89% of the combined voting power of the Company’s outstanding Class A Shares andClass B Shares; and     WHEREAS, as a condition to the willingness of the Company to commence the Tender Offer, theCompany has required that the Principal Stockholder enter into this Agreement with respect toVoting Securities (as hereinafter defined) the Principal Stockholder may directly or indirectly ownfrom time to time at or after the Post Closing Determination Time (as hereinafter defined) (the“Subject Shares”), it being understood that Voting Securities shall be Subject Shares onlyduring the period they are so owned.     NOW THEREFORE, in consideration of the mutual covenants and agreements set forth herein, theparties hereto agree as follows:**ARTICLE I****VOTING AGREEMENT**     SECTION 1.1 Voting Agreement. (a) The Principal Stockholder hereby agrees that during thetime this Agreement is in effect, at any meeting of the stockholders of the Company, howevercalled, or at any adjournment or postponement thereof (a “Company Stockholders’ Meeting”),or in any other circumstances upon which a vote, consent or other approval (including by writtenconsent) is sought by or from the stockholders of the Company, the Principal Stockholder shall (x)when a Company Stockholders’ Meeting is held, appear at such Company Stockholders’ Meeting orotherwise cause Subject Shares that represent Excess Voting Power to be counted as present thereatfor the purpose of establishing a quorum (except to the extent otherwise provided in theimmediately succeeding clause (y) with respect to non-affiliated shares which are not counted aspresent), and (y) cause Subject Shares that represent Excess Voting Power to be treated in the same manner (i.e.,not present (and, therefore, not
1

 
counted as present for quorum purposes), present but abstaining,voting for or voting against), and in proportion to, the votes or actions of all Companystockholders, including the vote or actions of the Principal Stockholder and his affiliateson the basis, solely for the purpose of determining proportionality, of one vote per Class A Share and Class B Share(even though the Class B Shares have ten votes per share), at any such CompanyStockholders’ Meeting or under any such other circumstances upon which a vote, consent or otherapproval (including by written consent) is sought by or from the stockholders of the Company. Forpurposes of this Agreement: (i) “Cap Amount” means the aggregate percentage voting powerrepresented by the Subject Shares of the combined voting power of the outstanding Voting Securitiesas of the Pre-Closing Determination Time (as hereinafter defined), (ii) “Excess VotingPower” (as calculated as of the Post Closing Determination Time and at such other subsequenttimes, from time to time, as required by this Agreement) means the aggregate percentage votingpower represented by the Subject Shares of the combined voting power of the outstanding VotingSecurities less the Cap Amount, adjusted in accordance with the first sentence of Section 1.1(b),(iii) “Pre-Closing Determination Time” means the date and time immediately prior to theExpiration Date (as hereinafter defined), (iv) “Post Closing Determination Time” means thedate and time immediately after the Expiration Date, (v) “Expiration Date” means the dateand time denominated as such with respect to the Tender Offer (including extensions thereof) in theSchedule TO, (vi) “Voting Securities” means securities of the Company having the powergenerally to vote on the election of directors and other matters submitted to a vote ofstockholders of the Company, and (vii) “affiliates” of the Principal Stockholder means anyperson or entity that directly, or indirectly through one of more intermediaries, controls, or iscontrolled by, or is under common control with, the Principal Stockholder.          (b) In calculating Excess Voting Power attributable to the Subject Shares: (i) there shallnot be taken into account, and the term Subject Shares shall not be deemed to include, the votingpower represented by any Class A Shares acquired by the Principal Stockholder after the PostClosing Determination Time (through his exercise of stock options, open market purchases oracquisition of shares in other post-Expiration Date transactions, other than share acquisitionsderived, directly or indirectly, from Class A or Class B Shares owned by the Principal Stockholderat the Post Closing Determination Time), and (ii) there shall be taken into account the votingpower represented by any Class A Shares issued to or acquired from third parties by the Companyafter the Post Closing Determination Time, including pursuant to the exercise of stock options,under employee benefit plans, in public or private transactions, in acquisition transactions, inopen market purchases or similar circumstances, which net issuances and acquisitions will impactthe calculation of the then applicable amount of the Excess Voting Power but not the Cap Amount.The provisions of Section 1.1(a) shall not apply to any Subject Shares which do not representExcess Voting Power.
2

 
     SECTION 1.2 Irrevocable Proxy. (a) As security for the Principal Stockholder’sobligations under Section 1.1, the Principal Stockholder hereby irrevocably constitutes andappoints the Company as his attorney and proxy in accordance with the Corporation Law, with fullpower of substitution and re-substitution, to cause his Subject Shares representing ExcessVoting Power to be counted as present at any CompanyStockholders’ Meeting (except to the extent otherwise provided in Section 1.1(a)(y) with respect tonon-affiliated shares which are not counted as present), to vote his Subject Shares representingExcess Voting Power at any Company Stockholders’ Meeting, and to execute consents in respect of hisSubject Shares representing Excess Voting Power as and to the extent provided in Section1.1. The Principal Stockholder hereby revokes all other proxies and powers of attorney withrespect to his Subject Shares representing Excess Voting Power that he may have heretofore
3

 
appointed or granted, and represents that any proxies heretofore given in respect of his SubjectShares representing Excess Voting Power, if any, are revocable.          (b) The Principal Stockholder hereby affirms that the irrevocable proxy set forth in thisSection 1.2 is given in connection with the commencement by the Company of the TenderOffer, and that such irrevocable proxy is given to induce the Company to so commence the TenderOffer and to secure the performance of the duties of the Principal Stockholder under thisAgreement. The Principal Stockholder hereby further affirms that the irrevocable proxy is coupledwith an interest and, except as set forth in this Section 1.2 or in Section 5.1, is intended to beirrevocable in accordance with the provisions of Section 212 of the Delaware General CorporationLaw. If for any reason the proxy granted herein is not irrevocable, then the Principal Stockholderagrees to vote his Subject Shares representing Excess Voting Power in accordance with Section 1.1above. The parties agree that the foregoing is a voting agreement created under Section 218(c) ofthe Delaware General Corporation Law.          (c) This irrevocable proxy shall automatically terminate on the Termination Date (ashereinafter defined). Prior to that date, this irrevocable proxy shall not be terminated by anyact of the Principal Stockholder or by operation of Law, whether by the death or incapacity of thePrincipal Stockholder or by the occurrence of any other event or events, it being understood thatactions taken by the Company hereunder prior to the Termination Date shall be and remain valid asif such death, incapacity or other event or events had not occurred, regardless of whether or notthe Company has received notice of the same.     SECTION 1.3 Acknowledgment. The Principal Stockholder hereby acknowledges that he hasreceived and reviewed of a copy of the Schedule TO.**ARTICLE II****REPRESENTATIONS AND WARRANTIES**