(1)

Each share of DSS Common Stock includes a right to purchase one one-thousandth of a share of Series B Participating Preferred Stock.

(2)

Includes 7,342,042 shares which have become available for issuance under the replenishment feature of the 1993 Long-Term Incentive Plan, as amended, and 3,671,021 shares reserved for issuance pursuant to the Employee Stock Purchase Plan, as amended.

(3)

Estimated in accordance with Rule 457(c) and 457(h) solely for the purpose of calculating the registration fee based on the average of the high and low price of the Company’s DSS Common Stock as reported on the New York Stock Exchange on September 8, 2005.

ITEM 3.           Incorporation of Documents by Reference.

                 There are hereby incorporated by reference in this Registration Statement the following documents and information heretofore filed with the Securities and Exchange Commission (the "Commission") (Quantum Corporation is sometimes referred to herein as the "Company"):

                 (a)      The Company's Annual Report on Form 10-K for the fiscal year ended March 31, 2005, filed with the Commission pursuant to Section 13 of the Securities Exchange Act of 1934, as amended (the "Exchange Act"), on June 8, 2005;

                 (b)      The Company’s Current Reports on Form 8-K filed with the Commission on April 7, 2005, May 10, 2005, May 26, 2005, June 2, 2005, July 26, 2005 and August 23, 2005;

                 (c)      The Company’s Quarterly Report on Form 10-Q for the quarter ended June 27, 2005, filed with the Commission pursuant to Section 13 of the Exchange Act on August 5, 2005;

                 (d)      The description of the Company's Common Stock and Preferred Share Purchase Rights contained in the Company's Registration Statement on Form 8-A filed with the Commission on July 21, 1999 pursuant to Section 12(b) of the Exchange Act and any amendment or report filed for the purpose of updating any such description;

           All documents filed by the Company pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act on or after the date of this Registration Statement and prior to the filing of a post-effective amendment to this Registration Statement which indicates that all securities offered pursuant to this Registration Statement have been sold or which deregisters all securities then remaining unsold shall be deemed to be incorporated by reference in this Registration Statement and to be part hereof from the date of filing of such documents.  Any statement contained in a document incorporated or deemed to be incorporated by reference in this Registration Statement shall be deemed to be modified or superseded for purposes of this Registration Statement to the extent that a statement contained herein modifies or supersedes such statement.  Any such statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute a part of this Registration Statement.

ITEM 4.      Description of Securities.

           Inapplicable.

ITEM 5.       Interests of Named Experts and Counsel.

           Inapplicable.

II-1

ITEM 6.     Indemnification of Directors and Officers.

           Section 145 of the Delaware General Corporation Law authorizes a court to award, or a corporation's Board of Directors to grant, indemnification to directors and officers in terms sufficiently broad to permit such indemnification under certain circumstances for liabilities (including reimbursement for expenses incurred) arising under the Securities Act of 1933, as amended.  The Company’s Amended and Restated Certificate of Incorporation contains a provision eliminating the personal liability of the Company’s directors to the Company or its stockholders for breach of fiduciary duty as a director to the fullest extent permitted by applicable law.  The Company's Bylaws, as amended, provide for the indemnification of its directors, officers, employees and other agents to the maximum extent permitted by Delaware General Corporation Law, and the Company has entered into agreements with its officers, directors and certain key employees implementing such indemnification.

ITEM 7.      Exemption from Registration Claimed.

           Inapplicable.

ITEM 8.      Exhibits.

Exhibit
Number

Description

4.1

1993 Long-Term Incentive Plan, which appears as Exhibit 99(d)(4) to the Company’s Schedule TO, filed with the Commission on June 4, 2001, which exhibit is incorporated herein by reference.

4.2

Amendment No. 1 to the 1993 Long-Term Incentive Plan, which appears as Exhibit 10.6 to the Company’s Form 10-Q for the period ending September 29, 2002, filed with the Commission on November 13, 2002, which exhibit is incorporated herein by reference.

4.3

Amended Employee Stock Purchase Plan, which appears as Exhibit 10.1 to the Company’s Form 8-K, filed with the Commission on November 18, 2004, which exhibit is incorporated herein by reference.

5.1

Opinion regarding legality of Wilson Sonsini Goodrich & Rosati, P.C.

23.1

Consent of Independent Registered Public Accounting Firm.

23.2

Consent of Wilson Sonsini Goodrich & Rosati, P.C. (included in Exhibit 5.1).

24.1

Power of Attorney (see page II-4).

ITEM 9.     Undertakings.

             A.    The undersigned registrant hereby undertakes:

                  (1)      To file, during any period in which offers or sales are being made, a post-effective amendment to this registration statement to include any material information with respect to the plan of distribution not previously disclosed in the registration statement or any material change to such information in the registration statement.

                  (2)      That, for the purpose of determining any liability under the Securities Act of 1933, as amended (the "Securities Act"), each such post-effective amendment shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

                  (3)      To remove from registration by means of a post-effective amendment any of the securities being registered which remain unsold at the termination of the offering.

             B.    The undersigned registrant hereby undertakes that, for purposes of determining any liability under the Securities Act, each filing of the registrant's annual report pursuant to Section 13(a) or Section 15(d) of the Exchange Act (and, where applicable, each filing of an employee benefit plan's annual report pursuant to Section 15(d) of the Exchange Act) that is incorporated by reference in the registration statement shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

             C.    Insofar as indemnification for liabilities arising under the Securities Act may be permitted to directors, officers and controlling persons of the Company pursuant to the foregoing provisions, or otherwise,  the Company has been advised that in the opinion of the Commission such indemnification is against public policy as expressed in the Securities Act and is, therefore, unenforceable.  In the event that a claim for indemnification against such liabilities (other than the payment by the Company in successful defense of any action, suit or proceeding) is asserted by such director, officer or controlling person in connection with the securities being registered hereunder, the Company will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question of whether such indemnification by it is against public policy as expressed in the Securities Act and will be governed by the final adjudication of such issue.

QUANTUM CORPORATION

By:    /s/ Edward J. Hayes, Jr.      

       Edward J. Hayes, Jr.

       Chief Financial Officer

Signature

Title

Date

   /s/ Richard E. Belluzzo             
            (Richard E. Belluzzo)

Chief Executive Officer and Chairman of the Board
(Principal Executive Officer)

September 12, 2005

   /s/Edward J. Hayes, Jr.             
           (Edward J. Hayes, Jr.)

Chief Financial Officer
(Principal Financial and Accounting Officer)

September 12, 2005

   /s/ Michael A. Brown               
           (Michael A. Brown)

Director

September 12, 2005

   /s/ Alan L. Earhart                  
           (Alan L. Earhart)

Director

September 12, 2005

   /s/ Edward M. Esber, Jr.             
           (Edward M. Esber, Jr.)

Director

September 12, 2005

   /s/ John M. Partridge                  
           (John M. Partridge)

Director

September 12, 2005

   /s/ Steven C. Wheelwright           
           (Steven C. Wheelwright)

Director

September 12, 2005

   /s/ Mary Agnes Wilderotter          
           (Mary Agnes Wilderotter)

Director

September 12, 2005

II-4

Exhibit
Number

Description

4.1

1993 Long-Term Incentive Plan, which appears as Exhibit 99(d)(4) to the Company’s Schedule TO, filed with the Commission on June 4, 2001, which exhibit is incorporated herein by reference.

4.2

Amendment No. 1 to the 1993 Long-Term Incentive Plan, which appears as Exhibit 10.6 to the Company’s Form 10-Q for the period ending September 29, 2002, filed with the Commission on November 13, 2002, which exhibit is incorporated herein by reference.

4.3

Amended Employee Stock Purchase Plan, which appears as Exhibit 10.1 to the Company’s Form 8-K, filed with the Commission on November 18, 2004, which exhibit is incorporated herein by reference.

5.1

Opinion regarding legality of Wilson Sonsini Goodrich & Rosati, P.C.

23.1

Consent of Independent Registered Public Accounting Firm.

23.2

Consent of Wilson Sonsini Goodrich & Rosati, P.C. (included in Exhibit 5.1).

24.1

Power of Attorney (see Page II-4 of Registration Statement).

Very truly yours,

/s/ Wilson Sonsini Goodrich & Rosati

WILSON SONSINI GOODRICH & ROSATI

Professional Corporation

/s/ Ernst & Young LLP