QUANTUM CORPORATION
 
AMENDMENT TO JON GACEK OFFER LETTER
 
     Quantum Corporation (the “Company”) and Jon Gacek (the “Executive”) entered
into an offer letter, dated August 25, 2006 (the “Offer Letter”) and an
amendment to the Offer Letter, dated August 18, 2008. This Amendment to the
Offer Letter is made as of January 28, 2010, by and between the Company and the
Executive.
 
RECITALS
 
     WHEREAS, the Company and the Executive desire to further amend the Offer
Letter to comply with the requirements of Section 409A of the Internal Revenue
Code of 1986, as amended.
 
     WHEREAS, under the Offer Letter, the Executive will be entitled a lump sum
cash payment if his employment is Involuntarily Terminated (as defined in, and
in the circumstances described in, the Offer Letter) and Executive executes and
does not revoke a separation agreement and general release of claims.
 
     NOW, THEREFORE, the Company and the Executive agree that in consideration
of the foregoing and the promises and covenants contained herein, the parties
agree as follows:
 
AGREEMENT
 
     1. Code Section 409A. The Code Section 409A paragraphs previously added to
the Offer Letter are hereby amended in their entirety to read as follows:
 
     “Notwithstanding anything to the contrary in this Offer Letter, no Deferred
Compensation Separation Benefits (as defined below) will be considered due or
payable until you have a “separation from service” within the meaning of Section
409A of the Internal Revenue Code of 1986, as amended, and the final regulations
and any guidance promulgated thereunder (“Section 409A”). In addition, if you
are a “specified employee” within the meaning of Section 409A at the time of
your separation from service (other than due to death), then the severance
benefits payable to you under this Offer Letter, if any, and any other severance
payments or separation benefits that may be considered deferred compensation
under Section 409A (together, the “Deferred Compensation Separation Benefits”)
otherwise due to you on or within the six (6) month period following your
separation from service will accrue during such six (6) month period and will
become payable in a lump sum payment (less applicable withholding taxes) on the
date six (6) months and one (1) day following the date of your separation from
service. All subsequent payments, if any, will be payable in accordance with the
payment schedule applicable to each payment or benefit. Notwithstanding anything
herein to the contrary, if you die following your separation from service but
prior to the six (6) month anniversary of your date of separation, then any
payments delayed in accordance with this paragraph will be payable in a lump sum
(less applicable withholding taxes) to your estate as soon as administratively
practicable after the date of your death and all other Deferred Compensation
Separation Benefits will be payable in accordance with the payment schedule
applicable to each payment or benefit.
 

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     It is the intent of this Offer Letter to comply with the requirements of
Section 409A so that none of the severance payments and benefits to be provided
hereunder will be subject to the additional tax imposed under Section 409A, and
any ambiguities herein will be interpreted to so comply. You and the Company
agree to work together in good faith to consider amendments to this Offer Letter
and to take such reasonable actions which are necessary, appropriate or
desirable to avoid imposition of any additional tax or income recognition under
Section 409A prior to actual payment to you.
 
     The separation agreement and general release required above must be
executed and not revoked within the period required by the release and in no
event later than sixty (60) days following your termination, inclusive of any
revocation period set forth in the release. Subject to the six (6) month delay
described above, if your employment ends on or before October 15 of a calendar
year, the Deferred Compensation Separation Benefits to which you are entitled
shall be paid by Quantum to you within ten (10) calendar days after the date the
separation agreement and general release becomes effective, but on or before
December 31 of that calendar year. If your employment ends after October 15 of a
calendar year, the Deferred Compensation Separation Benefits to which you are
entitled shall be paid by Quantum to you on the later of (a) the second payroll
date in the calendar year next following the calendar year in which your
employment has ended or (b) the first payroll date following the date the your
separation agreement and general release becomes effective, subject to the six
(6) month delay described above.”
 
     2. Full Force and Effect. To the extent not expressly amended hereby, the
Offer Letter shall remain in full force and effect.
 
     3. Entire Agreement. This Amendment and the Offer Letter between the
Executive and the Company, as amended, constitute the full and entire
understanding and agreement between the parties with regard to the subjects
hereof and thereof.
 
     4. Successors and Assigns. This Amendment and the rights and obligations of
the parties hereunder shall inure to the benefit of, and be binding upon, their
respective successors, assigns, and legal representatives.
 
     5. Counterparts. This Amendment may be executed in counterparts, all of
which together shall constitute one instrument, and each of which may be
executed by less than all of the parties to this Amendment.
 
     6. Governing Law. This Amendment shall be governed in all respects by the
internal laws of California, without regard to principles of conflicts of law.
 
     7. Amendment. Any provision of this Amendment may be amended, waived or
terminated by a written instrument signed by the Company and the Executive.
 
(Signature page follows)
 
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     IN WITNESS WHEREOF, the undersigned parties have caused this Amendment to
be executed as of the date first set forth above.
 

JON GACEK            QUANTUM CORPORATION     /s/ Jon Gacek /s/ Shawn Hall
Signature Signature   Jon Gacek Shawn Hall Print Name Print Name   Senior Vice
President, General Counsel Print Title

(Signature page to Amendment to Gacek Offer Letter)
 
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