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               QUANTUM
  CORPORATION 
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               QUANTUM
      CORPORATION 
            1650 TECHNOLOGY DRIVE SUITE 800 SAN JOSE, CA 95110  | 
          
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               Meeting
      Information 
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               Meeting Type:       Annual Meeting 
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               For holders as
      of:  June
      21, 2010 
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               Date:  
      August 18, 2010  
      Time: 8:00 AM, PDT 
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               Location:  
       
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               QUANTUM
      CORPORATION 
            Corporate Headquarters 1650 Technology Drive San Jose, CA 95110  | 
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               You are
      receiving this communication because you hold shares in the above named
      company. 
              This is not a ballot. You cannot
      use this notice to vote these shares. This communication presents only an
      overview of the more complete proxy materials that are available to you on
      the Internet. You may view the proxy materials online at www.proxyvote.com or easily request a
      paper copy (see reverse side). 
              We encourage you to access and
      review all of the important information contained in the proxy materials
      before voting. 
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               See the reverse
      side of this notice to obtain proxy materials and voting
      instructions. 
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               Proxy Materials Available to VIEW
      or RECEIVE: 
              NOTICE AND PROXY
      STATEMENT     ANNUAL REPORT    
      10-K COMBO 
              How to View
      Online:
       
              Have the information that is
      printed in the box marked by the arrow è XXXX XXXX XXXX available (located on the following
      page) and visit: www.proxyvote.com.  
              How to Request and Receive a PAPER
      or E-MAIL Copy: 
              If you want to receive a paper or e-mail copy of these documents, you must request one. There is NO charge for requesting a copy. Please choose one of the following methods to make your request: 1) BY INTERNET: www.proxyvote.com 2) BY TELEPHONE: 1-800-579-1639 3) BY E-MAIL*: sendmaterial@proxyvote.com *   If requesting materials by e-mail, please send a
      blank e-mail with the information that is printed in the box marked by the
      arrow è XXXX XXXX XXXX (located on the following page) in the
      subject line. 
              Requests, instructions and other
      inquiries sent to this e-mail address will NOT be forwarded to your
      investment advisor. Please make the request as instructed above on or
      before August 4, 2010 to facilitate timely delivery. 
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               Vote In Person: Many shareholder meetings have
      attendance requirements including, but not limited to, the possession of
      an attendance ticket issued by the entity holding the meeting. Please
      check the meeting materials for any special requirements for meeting
      attendance. At the meeting, you will need to request a ballot to vote
      these shares. 
              Vote By Internet:
      To vote now by
      Internet, go to www.proxyvote.com.
      Have the
      information that is printed in the box marked by the arrow è XXXX XXXX XXXX  available and follow the
      instructions.  
              Vote By Mail: You can vote by mail by requesting
      a paper copy of the materials, which will include a proxy
      card.  
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| Voting Items | |||
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               THE DIRECTORS RECOMMEND A VOTE
      "FOR" ITEMS 1 AND 2. 
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| 1. | Proposal to elect to the Board of Directors. | 
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               01)    Paul R. Auvil III 
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               05)    Edward M. Esber,
    Jr. 
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               02)    Richard E.
Belluzzo 
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               06)    Elizabeth A.
Fetter 
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               03)    Michael A. Brown 
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               07)    Joseph A. Marengi 
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               04)    Thomas S.
Buchsbaum 
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               08)    Dennis P. Wolf 
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| 2. | 
               Proposal to ratify the appointment
      of PricewaterhouseCoopers LLP as the independent registered public
      accounting firm of the Company for the fiscal year ending March 31,
      2011. 
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| 3. | 
               Proposal to transact such other
      business as may properly come before the meeting or any adjournment or
      postponement thereof. 
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