SecProbe.io

Mail Stop 4561
       May 12, 2009

Jon W. Gacek
Chief Financial Officer
Quantum Corporation
1650 Technology Drive, Suite 800
San Jose, CA 95110

Re: Quantum Corporation
 Form 10-K for Fiscal Year Ended March 31, 2008
Filed June 13, 2008
 File No. 001-13449

Dear Mr. Gacek:

We have reviewed your response letter  dated April 14, 2009 in connection with
the above-referenced filing and have the followi ng comments.  If indicated, we think you
should revise your document in response to these comments.  If you disagree, we will
consider your explanation as to why our comment is inapplicable or a revision is
unnecessary.  Please be as deta iled as necessary in your expl anation.  In some of our
comments, we may ask you to provide us w ith supplemental information so we may
better understand your disclosure.  After re viewing this information, we may raise
additional comments.  Unless otherwise noted, where prior comments are referred to they
refer to our letter dated March 31, 2009.

Form 10-K for Fiscal Year Ended March 31, 2008

Part II

Item 8.  Financial Statements and Supplementary Data

Note 3:  Summary of Significant Accounting Policies

Service Parts for Maintenance, page 59
1. Your response to prior comment number 7 indicates that a typical product has a
three to five year life span after wh ich you are committed to providing service for
an additional five years.  Please clarif y for us the period over which you provide
your general product warranty as compar ed to your separate extended warranty

Jon W. Gacek
Quantum Corporation
May 12, 2009 Page 2
contracts.  In this regard, we note your disclosure on page 59, which indicates you
generally provide a product wa rranty of 3 to 36 months.
2. We believe the model described in Q&A number 12 of TIS Section 2140 is the appropriate model to account for your serv ice parts for maintenance.  Please
provide an analysis that shows the impact  to the statements of operations of
recording the cost of parts in the peri ods in which they are actually used as
opposed to amortizing the cost of these parts over the expected period in which
they are used.  Additionally, it appears that the use of the inventory model may require you to re-evaluate your conclu sion with respect to balance sheet
classification.  Please also provide us with  an analysis of th e impact of these
changes on your previously-issued balance sh eets, including working capital.  If
you intend to classify a portion of these parts as long term within your balance
sheet, explain the basis for that conclusion and provide us with an analysis that
supports the amount.

Part III

Item 11.  Executive Compensation (incorporat ed by reference from Def 14A filed on
June 27, 2008)

Compensation Discussion and Analysis, page 19
3. We note your response to prior comment number 8.  When a named executive
officer’s individual performance has had a material effect on the compensation
paid to that officer, the company should disclose in its compensation discussion
and analysis how it evaluated the officer’s individua l performance, including
identifying any annual performance objectiv es assigned to that individual as well
as actual performance against those obj ectives.  Please c onfirm that you will
provide this disclosure in future filings.

Equity Compensation, page 23
4. We note your response to prior comment number 9.  The company’s explanation
as to how it determined the size of th e equity grants awarded to its named
executive officers is still too general.  Your  response indicates that the size of the
equity grants made in 2008 was based in part on equity grant guidelines
established by the company.  However, you do not disclose these guidelines.  You
indicate that your CEO recommended the si ze and form of the equity grants made
to your named executive officers based on several factors.  However, you do not
explain how your CEO weighed and applied these factors in each  individual case
to reach his recommendation.  Finally, it is unclear from your response whether the Leadership and Compensati on Committee adopted the CEO’s
recommendations or modified them base d on its own evaluation of the factors

Jon W. Gacek
Quantum Corporation
May 12, 2009 Page 3
identified or additional factors.  Please  confirm that in future filings you will
provide a more substantive analysis as to how you determined the equity grants made to each of your named executive officers.

* * * * * * *

Please respond to these comments within  10 business days or tell us when you
will provide us with a response.  Please  submit all correspondence and supplemental
materials on EDGAR as required by Rule 101 of Regulation S-T.  If you amend your
filing, you may wish to provide us with marked  copies of any amendment to expedite our
review.  Please furnish a cover letter th at keys your response to our comments and
provides any requested information.  Detailed co ver letters greatly faci litate our review.
Please understand that we may have addi tional comments after reviewing any
amendment and your response to our comments.

You may contact Jennifer F ugario, Staff Accountant, at (202) 551-3482, or Mark
Shannon, Staff Accountant, at  (202) 551-3299 if you have any questions regarding
comments on the financial statements and re lated matters.  Please address questions
regarding all other comments to Matthew Cr ispino, Staff Attorne y, at (202) 551-3456 or
Barbara C. Jacobs, Assistant Director, at ( 202) 551-3730.  If you need further assistance,
you may contact me at (202) 551-3226.

      S i n c e r e l y ,

     C r a i g  W i l s o n
Senior Assistant Chief Accountant