FORM 3
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940
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(Print or Type Responses)
1. Name and Address of Reporting Person *
  GACEK JON W
2. Date of Event Requiring Statement (Month/Day/Year)
08/22/2006
3. Issuer Name and Ticker or Trading Symbol
QUANTUM CORP /DE/ [DSS]
(Last)
(First)
(Middle)
C/O QUANTUM CORPORATION, 1650 TECHNOLOGY DRIVE, SUITE 700
4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
EVP & Chief Financial Officer
5. If Amendment, Date Original Filed(Month/Day/Year)
(Street)

SAN JOSE, CA 95110
6. Individual or Joint/Group Filing(Check Applicable Line)
_X_ Form filed by One Reporting Person
___ Form filed by More than One Reporting Person
(City)
(State)
(Zip)
Table I - Non-Derivative Securities Beneficially Owned
1.Title of Security
(Instr. 4)
2. Amount of Securities Beneficially Owned
(Instr. 4)
3. Ownership Form: Direct (D) or Indirect (I)
(Instr. 5)
4. Nature of Indirect Beneficial Ownership
(Instr. 5)

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly. SEC 1473 (7-02)
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Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 4)
2. Date Exercisable and Expiration Date
(Month/Day/Year)
3. Title and Amount of Securities Underlying Derivative Security
(Instr. 4)
4. Conversion or Exercise Price of Derivative Security 5. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 5)
6. Nature of Indirect Beneficial Ownership
(Instr. 5)
Date Exercisable Expiration Date Title Amount or Number of Shares
Non-Qualified Stock Option 08/22/2006(1) 05/15/2007 DSS Common Stock 179,268 $ 1.41 D  
Non-Qualified Stock Option 08/22/2006(1) 08/14/2012 DSS Common Stock 59,756 $ 0.88 D  
Non-Qualified Stock Option 08/22/2006(1) 02/12/2013 DSS Common Stock 29,878 $ 1 D  
Non-Qualified Stock Option 08/22/2006(1) 08/13/2013 DSS Common Stock 179,268 $ 1.71 D  
Non-Qualified Stock Option 08/22/2006(1) 08/13/2014 DSS Common Stock 119,512 $ 1.52 D  
Non-Qualified Stock Option 08/22/2006(1) 08/22/2010 DSS Common Stock 239,024 $ 1.46 D  
Non-Qualified Stock Option (2) 09/01/2006(3) 09/01/2013 DSS Common Stock 1,000,000 $ 2.15 D  
Restricted Stock Units   (4)   (4) DSS Common Stock 100,000 $ (6) D  
Restricted Stock Units   (5)   (5) DSS Common Stock 200,000 $ (6) D  

Reporting Owners

Reporting Owner Name / Address Relationships
Director 10% Owner Officer Other
GACEK JON W
C/O QUANTUM CORPORATION
1650 TECHNOLOGY DRIVE, SUITE 700
SAN JOSE, CA 95110
      EVP & Chief Financial Officer  

Signatures

/s/ Zoey Armstrong, by Zoey Armstrong, Attorney in Fact for Jon C. Gacek 09/05/2006
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 5(b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1) These options were granted under the 1999 Stock Incentive Plan of Advanced Digital Information Corporation ("ADIC"), which were assumed by Quantum Corporation ("Quantum") on August 22, 2006, pursuant to the Agreement and Plan of Merger (the "Merger Agreement") between ADIC and Quantum. The options were exchanged for options to purchase Quantum common stock, at an exchange ratio of 5.9756 per share, and are immediately vested.
(2) 'Right to Buy' granted under 16b-3 Plan.
(3) Stock Options will vest over a period of three (3) years, as follows: the first 33% will vest on September 1, 2007 with the remainder vesting in equal annual installments over the following two (2) years.
(4) Restricted Stock Units will vest over a period of two (2) years, as follows: the first 50% will vest on September 1, 2007 and the remaining 50% on September 1, 2008.
(5) Restricted Stock Units will vest over a period of three (3) years, as follows: the first 33% will vest on September 1, 2007 with the remainder vesting in equal annual installments over the following two (2) years.
(6) Restricted Stock Units convert to shares of Common Stock on a 1-for-1 basis.

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