<PAGE>

================================================================================


                                   MCSI, INC.
                                AS THE BORROWER
                                      AND

                    THE FINANCIAL INSTITUTIONS NAMED HEREIN

                                   AS LENDERS

                               NATIONAL CITY BANK
                     AS A LENDER AND AS DOCUMENTATION AGENT

                         PNC BANK, NATIONAL ASSOCIATION
                       AS A LENDER, THE SWING LINE LENDER
                           A LETTER OF CREDIT ISSUER
                          AND AS ADMINISTRATIVE AGENT

                              ---------------------
                                AMENDMENT NO. 9
                                  DATED AS OF
                                  MAY 31, 2000
                                       TO
                     AMENDED AND RESTATED CREDIT AGREEMENT
                                  DATED AS OF
                                DECEMBER 1, 1998

                             ---------------------

================================================================================

<PAGE>

                                AMENDMENT NO. 9
                                       TO
                     AMENDED AND RESTATED CREDIT AGREEMENT

        THIS AMENDMENT NO. 9 TO AMENDED AND RESTATED CREDIT AGREEMENT, dated as
of May 31, 2000 ("THIS AMENDMENT"), among:

                  (i) MCSi, Inc., a Maryland corporation which is the successor
        by merger to Miami Computer Supply Corporation, an Ohio corporation
        (herein, together with its successors and assigns, the "BORROWER");

                 (ii) the financial institutions listed on the signature pages
        hereof (the "LENDERS");

                (iii) NATIONAL CITY BANK, a national banking association, as a
        Lender and as Documentation Agent; and

                 (iv) PNC BANK, NATIONAL ASSOCIATION, a national banking
        association, as a Lender, the Swing Line Lender, a Letter of Credit
        Issuer and as Administrative Agent (the "ADMINISTRATIVE AGENT") for the
        Lenders under the Credit Agreement:

PRELIMINARY STATEMENTS:

        (1) The Borrower, the Lenders named therein, and the Administrative
Agent entered into the Amended and Restated Credit Agreement, dated as of
December 1, 1998, as amended by Amendment No. 1 thereto, dated as of March 31,
1999, Amendment No. 2 thereto, dated as of April 19, 1999, Amendment No. 3
thereto, dated as of August 13, 1999, Amendment No. 4 thereto, dated as of
August 31, 1999, Amendment No. 5 thereto, dated as of December 20, 1999,
Amendment No. 6 thereto, dated as of January 10, 2000, Amendment No. 7 thereto,
dated as of February 4, 2000, and Amendment No. 8 thereto, dated as of April 30,
2000 (as so amended, the "CREDIT AGREEMENT"; with the terms defined therein, or
the definitions of which are incorporated therein, being used herein as so
defined).

        (2) Pursuant to Amendment No. 7 to Amended and Restated Credit
Agreement, dated as of February 4, 2000 ("AMENDMENT NO. 7"), the Credit
Agreement was amended to provide, among other things, for a temporary increase
in the Total General Revolving Commitment from $160,000,000 to $175,000,000, and
the Lenders made General Revolving Loans to the Borrower reflecting usage of
such temporary increase (such General Revolving Loans reflecting such usage are
referred to herein as "BRIDGE LOANS").

        (3) Pursuant to Amendment No. 8 to Amended and Restated Credit
Agreement, dated as of April 30, 2000 ("AMENDMENT NO. 8"), the Credit Agreement
was amended to extend the maturity of the Bridge Loans and such temporary
increase in the Total General Revolving Commitment from April 30, 2000 to May
31, 2000, to increase the interest rate margins applicable to the Bridge Loans,
and otherwise to amend certain provisions of the Credit Agreement, all as more
fully set forth therein.

        (4) The parties hereto desire to extend the maturity of the Bridge Loans
and such temporary increase in the Total General Revolving Commitment from May
31, 2000 to June 30, 2000, all as more fully set forth below.

        NOW, THEREFORE, the parties hereby agree as follows:

        1.     AMENDMENTS, ETC.

        1.1.   EXTENSION OF TEMPORARY INCREASE IN TOTAL GENERAL REVOLVING
COMMITMENT, ETC. Effective on and after June 1, 2000, section 1.1 of Amendment
No. 8 is superceded by the following:

<PAGE>

        (a) Effective only during the period from February 4, 2000 through June
30, 2000, the Total General Revolving Commitment shall be increased from
$160,000,000 to $175,000,000, and the General Revolving Commitments of the
Lenders set forth in Annex I to the Credit Agreement shall be amended to reflect
the following:

<TABLE>
<CAPTION>
Lender                                       General Revolving Commitment
------                                       ----------------------------
<S>                                          <C>
PNC Bank, National Association                     $27,343,750
National City Bank                                 $27,343,750
Key Corporate Capital Inc.                         $27,343,750
Bank One, Indiana, N. A.                           $27,343,750
Firstar Bank, N. A.                                $27,343,750
The Huntington National Bank                       $27,343,750
The Provident Bank                                 $10,937,500
                                                  ------------
    TOTAL                                         $175,000,000
                                                  ============
</TABLE>

        (b) For the avoidance of doubt, it is noted that the Borrower has the
right to make permanent reductions in the amount of the Total General Revolving
Commitment in accordance with the provisions of section 4.2(c) of the Credit
Agreement. If as of 5:00 P. M. (local time at the Notice Office of the
Administrative Agent) on June 30, 2000, the Total General Revolving Commitment
shall not previously have been permanently reduced to $160,000,000 or less by a
voluntary and permanent reduction made in accordance with the provisions of
section 4.2(c) of the Credit Agreement, then effective as of such time the Total
General Revolving Commitment shall be automatically and permanently reduced from
$175,000,000 to $160,000,000, and Annex I to the Credit Agreement shall be
amended to reflect the reduced General Revolving Commitments of the Lenders as
follows:

<TABLE>
<CAPTION>
Lender                                       General Revolving Commitment
------                                       ----------------------------
<S>                                          <C>
PNC Bank, National Association                     $25,000,000
National City Bank                                 $25,000,000
Key Corporate Capital Inc.                         $25,000,000
Bank One, Indiana, N. A.                           $25,000,000
Firstar Bank, N. A.                                $25,000,000
The Huntington National Bank                       $25,000,000
The Provident Bank                                 $10,000,000
                                                  ------------
    TOTAL                                         $160,000,000
                                                  ============
</TABLE>

        (c) To the extent that General Revolving Loans outstanding under the
Credit Agreement reflect a usage of the temporary increase in the Total General
Revolving Commitment from $160,000,000 to $175,000,000 effected by this
Amendment (General Revolving Loans reflecting such usage are referred to herein
as "BRIDGE LOANS"), THEN notwithstanding anything to the contrary contained in
the Credit Agreement, (i) the Applicable Prime Rate Margin for Bridge Loans
which are Prime Rate Loans shall be 200 basis points for any period ending April
30, 2000 or prior thereto, and 250 basis points for any period thereafter, and
(ii) the Applicable Eurodollar Margin for Bridge Loans which are Eurodollar
Loans shall be 400 basis points for any period (or portion of a period) ending
April 30, 2000 or prior thereto, and 450 basis points for any period (or portion
of a period) thereafter.

        (d) The only Interest Period which shall be available for a Bridge Loan
which is a Eurodollar Loan is an Interest Period of one month, subject to
Continuation for additional Interest Periods as provided in section 2.8 of the
Credit Agreement. No Interest Period for a Bridge Loan which is a Eurodollar
Loan may be selected which would end after June 30, 2000.

        1.2.   AMENDMENT OF BRIDGE NOTES. The General Revolving Notes previously
issued to the Lenders evidencing the Bridge Loans are hereby amended to (i)
change the maturity date specified therein from May 31, 2000 to June 30, 2000,
and (ii) change references therein to "Amendment No. 7 to Credit Agreement"
and/or to "Amendment No. 8 to Credit Agreement", to include the amendments
provided for in this Amendment. Each Lender agrees to firmly attach a notation
to such effect to its General Revolving Note evidencing its Bridge Loans prior
to any transfer thereof.

                                       2

<PAGE>

        1.3.   CONSENT TO REINCORPORATION, ETC. (a) Notwithstanding anything to
the contrary contained in section 9.2 or any other provision of the Credit
Agreement or in any of the other Credit Documents, the Administrative Agent and
the Lenders hereby consent to the merger of the Borrower into a newly organized
Maryland corporation named "MCSi, Inc." in connection with the reincorporation
transaction described in the Borrower's Proxy Statement dated April 12, 2000 for
its Annual Meeting of Stockholders on May 9, 2000. The Borrower signatory to
this Amendment is the Maryland corporation which is the surviving corporation of
such merger, and as such surviving corporation hereby unconditionally assumes
all of the obligations of Miami Computer Supply Corporation, an Ohio
corporation, under the Credit Agreement and all of the other Credit Documents,
including without limitation any such obligations which may be contingent or
which may relate to periods, events or circumstances existing or arising prior
to the effective date of such merger.

        (b) All references in the Credit Agreement and in any of the other
Credit Documents to the Borrower as an Ohio corporation are hereby changed to
refer to the Borrower as a Maryland corporation whose name is "MCSi, Inc.".

        1.4.   AMENDMENT FEE. As consideration for the changes in the Credit
Agreement effected by sections 1.1 through 1.3 of this Amendment, the Borrower
will pay to the Administrative Agent, for PRO RATA distribution among the
Lenders in accordance with their respective General Revolving Commitments, (i)
an amendment fee in the aggregate amount of $15,000, such amendment fee being
payable in immediately available funds on the date this Amendment becomes
effective as provided in section 3 hereof, and (ii) if as of June 15, 2000, the
Total General Revolving Commitment shall not previously have been permanently
reduced to $160,000,000 or less by a voluntary and permanent reduction made in
accordance with the provisions of section 4.2(c) of the Credit Agreement, an
additional amendment fee in the aggregate amount of $15,000, such additional
amendment fee being payable in immediately available funds on June 15, 2000.

        2.     REPRESENTATIONS AND WARRANTIES.

        The Borrower represents and warrants to the Lenders and the
Administrative Agent as follows:

        2.1.   AUTHORIZATION, VALIDITY AND BINDING EFFECT. This Amendment has
been duly authorized by all necessary corporate action on the part of the
Borrower, has been duly executed and delivered by a duly authorized officer
or officers of the Borrower, and constitutes the valid and binding agreement
of the Borrower, enforceable against the Borrower in accordance with its
terms.

        2.2.   REPRESENTATIONS AND WARRANTIES TRUE AND CORRECT. The
representations and warranties of the Borrower contained in the Credit
Agreement, as amended hereby, are true and correct on and as of the date hereof
as though made on and as of the date hereof, except to the extent that such
representations and warranties expressly relate to a specified date, in which
case such representations and warranties are hereby reaffirmed as true and
correct when made.

        2.3.   NO EVENT OF DEFAULT, ETC. No condition or event has occurred or
exists which constitutes or which, after notice or lapse of time or both, would
constitute an Event of Default.

        2.4.   COMPLIANCE. The Borrower is in full compliance with all covenants
and agreements contained in the Credit Agreement, as amended hereby.

        2.5.   RECENT FINANCIAL STATEMENTS. The Borrower has furnished to the
Lenders and the Administrative Agent complete and correct copies of the audited
condensed consolidated balance sheet of the Borrower and its consolidated
subsidiaries as of December 31, 1999, and the related audited condensed
consolidated statements of income and of cash flows of the Borrower and its
consolidated subsidiaries for the fiscal year then ended, as contained in the
Form 10-K Annual Report of the Borrower which was filed with the SEC. All such
financial statements have been prepared in accordance with GAAP, consistently
applied (except as stated therein), and fairly present the financial position of
the Borrower and its consolidated subsidiaries as of the date indicated and the
consolidated results of their operations and cash flows for the period
indicated.

                                       3

<PAGE>

        3.     EFFECTIVENESS.

        This Amendment shall become effective on a date (the "EFFECTIVE DATE"),
on or before June 1, 2000, if the following conditions are satisfied on or
before the Effective Date:

               (a) this Amendment shall have been executed by the Borrower and
        the Administrative Agent, and counterparts hereof as so executed shall
        have been delivered to the Administrative Agent;

               (b) the Acknowledgment and Consent appended hereto shall have
        been executed by the Credit Parties named therein, and counterparts
        hereof as so executed shall have been delivered to the Administrative
        Agent;

               (c) the Administrative Agent shall have been notified by all of
        the Lenders that such Lenders have executed this Amendment (which
        notification may be by facsimile or other written confirmation of such
        execution); and

               (d) the Borrower shall have paid to the Administrative Agent,
        for the account of the Lenders, such amendment fees as are payable at
        such time as provided in section 1.4 of this Amendment (the
        Administrative Agent hereby agreeing to promptly re-transmit pro rata
        portions of the amendment fees to the respective Lenders).

Subject to satisfaction of the foregoing conditions, the Administrative Agent
shall notify the Borrower and each Lender in writing of the effectiveness
hereof.

        4.     RATIFICATIONS.

        The terms and provisions set forth in this Amendment shall modify and
supersede all inconsistent terms and provisions set forth in the Credit
Agreement, and except as expressly modified and superseded by this Amendment,
the terms and provisions of the Credit Agreement are ratified and confirmed and
shall continue in full force and effect.

        5.     MISCELLANEOUS.

        5.1.   SUCCESSORS AND ASSIGNS. This Amendment shall be binding upon and
inure to the benefit of the Borrower, each Lender and the Administrative Agent
and their respective permitted successors and assigns.

        5.2.   SURVIVAL OF REPRESENTATIONS AND WARRANTIES. All
representations and warranties made in this Amendment shall survive the
execution and delivery of this Amendment, and no investigation by the
Administrative Agent or any Lender or any subsequent Loan or issuance of a
Letter of Credit shall affect the representations and warranties or the right
of the Administrative Agent or any Lender to rely upon them.

        5.3.   REFERENCE TO CREDIT AGREEMENT. The Credit Agreement and any
and all other agreements, instruments or documentation now or hereafter
executed and delivered pursuant to the terms of the Credit Agreement as
amended hereby, are hereby amended so that any reference therein to the
Credit Agreement shall mean a reference to the Credit Agreement as amended
hereby.

        5.4.   EXPENSES. As provided in the Credit Agreement, but without
limiting any terms or provisions thereof, the Borrower agrees to pay on
demand all costs and expenses incurred by the Administrative Agent in
connection with the preparation, negotiation, and execution of this
Amendment, including without limitation the costs and fees of the
Administrative Agent's special legal counsel, regardless of whether this
Amendment becomes effective in accordance with the terms hereof, and all
costs and expenses incurred by the Administrative Agent or any Lender in
connection with the enforcement or preservation of any rights under the
Credit Agreement, as amended hereby.

                                       4

<PAGE>

        5.5.   SEVERABILITY. Any term or provision of this Amendment held by a
court of competent jurisdiction to be invalid or unenforceable shall not impair
or invalidate the remainder of this Amendment and the effect thereof shall be
confined to the term or provision so held to be invalid or unenforceable.

        5.6.   APPLICABLE LAW. This Amendment shall be governed by and construed
in accordance with the laws of the State of Ohio.

        5.7.   HEADINGS. The headings, captions and arrangements used in this
Amendment are for convenience only and shall not affect the interpretation of
this Amendment.

        5.8.   ENTIRE AGREEMENT. This Amendment is specifically limited to the
matters expressly set forth herein. This Amendment and all other instruments,
agreements and documentation executed and delivered in connection with this
Amendment embody the final, entire agreement among the parties hereto with
respect to the subject matter hereof and supersede any and all prior
commitments, agreements, representations and understandings, whether written or
oral, relating to the matters covered by this Amendment, and may not be
contradicted or varied by evidence of prior, contemporaneous or subsequent oral
agreements or discussions of the parties hereto. There are no oral agreements
among the parties hereto relating to the subject matter hereof or any other
subject matter relating to the Credit Agreement.

        5.9.   COUNTERPARTS. This Amendment may be executed by the parties
hereto separately in one or more counterparts, each of which when so executed
shall be deemed to be an original, but all of which when taken together shall
constitute one and the same agreement.

                                       5

<PAGE>

        IN WITNESS WHEREOF, this Amendment has been duly executed and delivered
as of the date first above written.

<TABLE>
<S>                                         <C>
MCSI, INC.,                                 PNC BANK, NATIONAL ASSOCIATION,
   A MARYLAND CORPORATION WHICH IS THE         INDIVIDUALLY AS A LENDER, A LETTER
   SUCCESSOR BY MERGER TO MIAMI COMPUTER       OF CREDIT ISSUER, THE SWING LINE
   SUPPLY CORPORATION, AN OHIO CORPORATION     LENDER AND AS ADMINISTRATIVE AGENT

BY: /s/ Ira Stanley                         BY: /s/ [ILLEGIBLE]
    --------------------------------            ---------------------------------
     TITLE:                                       VICE PRESIDENT

NATIONAL CITY BANK,                         FIRSTAR BANK, N.A.
   INDIVIDUALLY AS A LENDER AND
   AS DOCUMENTATION AGENT

BY: /s/ [ILLEGIBLE]                         BY: /s/ [ILLEGIBLE]
    --------------------------------            ---------------------------------
        TITLE: VICE PRESIDENT                     TITLE: VICE PRESIDENT

KEY CORPORATE CAPITAL INC.                  THE HUNTINGTON NATIONAL BANK


BY:/s/ [ILLEGIBLE]                          BY: /s/ Julie [ILLEGIBLE]
    --------------------------------            ---------------------------------
     TITLE: AVP                                   TITLE: ASSISTANT VICE PRESIDENT

BANK ONE, INDIANA, N.A.                     THE PROVIDENT BANK


BY:/s/ Edward [ILLEGIBLE]                   BY: /s/ [ILLEGIBLE]
    --------------------------------            ---------------------------------
       TITLE: FIRST VICE PRESIDENT                TITLE: VICE PRESIDENT
</TABLE>

                                       6

<PAGE>

                           ACKNOWLEDGMENT AND CONSENT

        For the avoidance of doubt, and without limitation of the intent and
effect of sections 6 and 10 of the Amended and Restated Subsidiary Guaranty (as
such term is defined in the Credit Agreement referred to in the Amendment No. 9
to Amended and Restated Credit Agreement (the "AMENDMENT"), to which this
Acknowledgment and Consent is appended), each of the undersigned hereby
unconditionally and irrevocably (i) acknowledges receipt of a copy of the Credit
Agreement and the Amendment, and (ii) consents to all of the terms and
provisions of the Credit Agreement as amended by the Amendment.

        Capitalized terms which are used herein without definition shall have
the respective meanings ascribed thereto in the Credit Agreement referred to
herein. This Acknowledgment and Consent is for the benefit of the Lenders and
the Administrative Agent, any other person who is a third party beneficiary of
the Subsidiary Guaranty, and their respective successors and assigns. No term or
provision of this Acknowledgment and Consent may be modified or otherwise
changed without the prior written consent of the Administrative Agent, given as
provided in the Credit Agreement. This Acknowledgment and Consent shall be
binding upon the successors and assigns of each of the undersigned. This
Acknowledgment and Consent may be executed by any of the undersigned in separate
counterparts, each of which shall be an original and all of which together shall
constitute one and the same instrument.

        IN WITNESS WHEREOF, each of the undersigned has duly executed and
delivered this Acknowledgment and Consent as of the date of the Amendment
referred to herein.

Diversified Data Products, Inc.         Electronic Image Systems, Inc.
Computer Showcase, Inc.                 Consolidated Media Systems, Inc.



BY: /s/ Michael E. Peppel               BY: /s/ Ira Stanley
    --------------------------------        ---------------------------------
     Michael E. Peppel, an officer           Ira Stanley, an officer