Page 1 of 12 Pages UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 13G Under the Securities exchange Act of 1934 (AMENDMENT NO.4)* QUANTUM CORP ----------------------------------------------------- (NAME OF ISSUER) COM DSSG ----------------------------------------------------- (TITLE OF CLASS OF SECURITIES) 747906204 ----------------------------------------------------- (CUSIP NUMBER) December 31, 2003 ----------------------------------------------------- (Date of event which requires filing of this Statement) NOTE: A MAJORITY OF THE SHARES REPORTED IN THIS SCHEDULE 13G ARE HELD BY UNAFFILIATED THIRD-PARTY CLIENT ACCOUNTS MANAGED BY ALLIANCE CAPITAL MANAGEMENT L.P., AS INVESTMENT ADVISER. (ALLIANCE CAPITAL MANAGEMENT L.P. IS A MAJORITY-OWNED SUBSIDIARY OF AXA FINANCIAL, INC.) Check the appropriate box to designate the rule pursuant to which this Schedule is filed: X Rule 13d-1(b) Rule 13d-1(c) Rule 13d-1(d) * The remainder of this cover page shall be filled out for a reporting person's initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page. The information required in the remainder of this cover page shall not be deemed to be 'filed' for the purpose of Section 18 of the Securities Exchange Act of 1934 ('Act') or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes). (CONTINUED ON FOLLOWING PAGE(S)) CUSIP NO. 747906204 13G Page 2 of 12 Pages 1. NAME OF REPORTING PERSON S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON AXA Assurances I.A.R.D. Mutuelle 2. CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP * (A) [X] (B) [ ] 3. SEC USE ONLY 4. CITIZENSHIP OR PLACE OF ORGANIZATION France NUMBER OF SHARES 5. SOLE VOTING POWER 5,496,201 BENEFICIALLY OWNED AS OF 6. SHARED VOTING POWER 3,200 December 31, 2003 BY EACH 7. SOLE DISPOSITIVE POWER 7,362,630 REPORTING PERSON WITH: 8. SHARED DISPOSITIVE POWER 0 9. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH 7,362,630 REPORTING PERSON (Not to be construed as an admission of beneficial ownership) 10. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES * | | 11. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9 4.1% 12. TYPE OF REPORTING PERSON * IC * SEE INSTRUCTIONS BEFORE FILLING OUT! CUSIP NO. 747906204 13G Page 3 of 12 Pages 1. NAME OF REPORTING PERSON S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON AXA Assurances Vie Mutuelle 2. CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP * (A) [X] (B) [ ] 3. SEC USE ONLY 4. CITIZENSHIP OR PLACE OF ORGANIZATION France NUMBER OF SHARES 5. SOLE VOTING POWER 5,496,201 BENEFICIALLY OWNED AS OF 6. SHARED VOTING POWER 3,200 December 31, 2003 BY EACH 7. SOLE DISPOSITIVE POWER 7,362,630 REPORTING PERSON WITH: 8. SHARED DISPOSITIVE POWER 0 9. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH 7,362,630 REPORTING PERSON (Not to be construed as an admission of beneficial ownership) 10. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES * | | 11. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9 4.1% 12. TYPE OF REPORTING PERSON * IC * SEE INSTRUCTIONS BEFORE FILLING OUT! CUSIP NO. 747906204 13G Page 4 of 12 Pages 1. NAME OF REPORTING PERSON S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON AXA Courtage Assurance Mutuelle 2. CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP * (A) [X] (B) [ ] 3. SEC USE ONLY 4. CITIZENSHIP OR PLACE OF ORGANIZATION France NUMBER OF SHARES 5. SOLE VOTING POWER 5,496,201 BENEFICIALLY OWNED AS OF 6. SHARED VOTING POWER 3,200 December 31, 2003 BY EACH 7. SOLE DISPOSITIVE POWER 7,362,630 REPORTING PERSON WITH: 8. SHARED DISPOSITIVE POWER 0 9. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH 7,362,630 REPORTING PERSON (Not to be construed as an admission of beneficial ownership) 10. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES * | | 11. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9 4.1% 12. TYPE OF REPORTING PERSON * IC * SEE INSTRUCTIONS BEFORE FILLING OUT! CUSIP NO. 747906204 13G Page 5 of 12 Pages 1. NAME OF REPORTING PERSON S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON AXA 2. CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP * (A) [ ] (B) [ ] 3. SEC USE ONLY 4. CITIZENSHIP OR PLACE OF ORGANIZATION France NUMBER OF SHARES 5. SOLE VOTING POWER 5,496,201 BENEFICIALLY OWNED AS OF 6. SHARED VOTING POWER 3,200 December 31, 2003 BY EACH 7. SOLE DISPOSITIVE POWER 7,362,630 REPORTING PERSON WITH: 8. SHARED DISPOSITIVE POWER 0 9. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH 7,362,630 REPORTING PERSON (Not to be construed as an admission of beneficial ownership) 10. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES * | | 11. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9 4.1% 12. TYPE OF REPORTING PERSON * IC * SEE INSTRUCTIONS BEFORE FILLING OUT! CUSIP NO. 747906204 13G Page 6 of 12 Pages 1. NAME OF REPORTING PERSON S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON AXA Financial, Inc. 13-3623351 2. CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP * (A) [ ] (B) [ ] 3. SEC USE ONLY 4. CITIZENSHIP OR PLACE OF ORGANIZATION State of Delaware NUMBER OF SHARES 5. SOLE VOTING POWER 5,496,201 BENEFICIALLY OWNED AS OF 6. SHARED VOTING POWER 3,200 December 31, 2003 BY EACH 7. SOLE DISPOSITIVE POWER 7,362,630 REPORTING PERSON WITH: 8. SHARED DISPOSITIVE POWER 0 9. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH 7,362,630 REPORTING PERSON (Not to be construed as an admission of beneficial ownership) 10. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES * | | 11. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9 4.1% 12. TYPE OF REPORTING PERSON * HC * SEE INSTRUCTIONS BEFORE FILLING OUT! 13G Page 7 of 12 Pages Item 1(a) Name of Issuer: QUANTUM CORP Item 1(b) Address of Issuer's Principal Executive Offices: 501 Sycamore Drive Milpitas, CA 95035 Item 2(a) and (b) Name of Person Filing and Address of Principal Business Office: AXA Assurances I.A.R.D Mutuelle, and AXA Assurances Vie Mutuelle, 370, rue Saint Honore 75001 Paris, France AXA Courtage Assurance Mutuelle 26, rue Louis le Grand 75002 Paris, France as a group (collectively, the 'Mutuelles AXA'). AXA 25, avenue Matignon 75008 Paris, France AXA Financial, Inc. 1290 Avenue of the Americas New York, New York 10104 (Please contact Dean Dubovy at (212) 314-5528 with any 13G Page 8 of 12 Pages Item 2(c) Citizenship: Mutuelles AXA and AXA - France AXA Financial, Inc. - Delaware Item 2(d) Title of Class of Securities: COM DSSG Item 2(e) Cusip Number: 747906204 Item 3. Type of Reporting Person: AXA Financial, Inc. as a parent holding company, in accordance with 240.13d-1(b)(ii)(G). The Mutuelles AXA, as a group, acting as a parent holding company. AXA as a parent holding company. 13G Page 9 of 12 Pages 第四项。(a)有权受益者拥有的数量:7,362,630股普通股，包括:

股份数目--------------------- The Mutuelles AXA, as a group 0 AXA 0 AXA Entity or Entities AXA Financial, Inc. 0 Subsidiaries: Alliance Capital Management L.P. acquired solely for investment purposes on behalf of client discretionary investment advisory accounts: Common Stock 7,362,630 7,362,630 ------------- Total 7,362,630 ============= Each of the Mutuelles AXA, as a group, and AXA expressly declares that the filing of this Schedule 13G shall not be construed as an admission that it is, for purposes of Section 13(d) of the Exchange Act, the beneficial owner of any securities covered by this Schedule 13G. Each of the above subsidiaries of AXA Financial, Inc. operates under independent management and makes independent decisions. 类（b）的百分比：4.1％=============

第四项。(c)视为投票权和处分权:

（ⅰ）（ⅱ）（ⅲ）（ⅳ）被当作视同视同视为已不得不要有鞋底功率共享电源鞋底电源共享的电源进行投票进行投票，以处置处置或或或或以直接直接直接直接的表决投票处置处置------------ ------------ ------------ ------------ 该Mutuelles AXA，为一组0 0 0 0 AXA 0 0 0 0 AXA实体或实体：AXA金融公司0 0 0 0子公司： - ------------联合资本5496201 3200 73626300 Management L.P. ------------ ------------ ------------ ------------ 5,496,201 3,200 7,362,630 0 ============ ============ ============ ============ Each of the above subsidiaries of AXA Financial, Inc. operates under independent management and makes independent voting and investment decisions.

第11页，共12页某一类别百分之五或以下的所有权:如果本声明是为了报告截至(X)第6项的事实。代表他人拥有百分之五以上的股份。N / 7项。母公司控股公司购买证券的子公司的识别和分类:本附表13G由安盛金融有限公司提交;亚搏官网app登录入口拥有安盛金融(AXA Financial, Inc.)的安盛集团(AXA);Mutuelles安盛,作为一个群体控制安盛:()在Mutuelles安盛的能力,作为一个群体,作为母公司控股公司对持有以下安盛实体或实体:在安盛的能力()的控股母公司控股公司对以下安盛实体或实体:亚搏官网app登录入口(X) Alliance Capital Management L.P.(13-3434400)，根据1940年《投亚搏官网app登录入口资顾问法案》第203条注册的投资顾问。美国公平人寿保险协会(13-5570651)，一家根据1940年《投资顾问法案》第203条注册的保险公司和投资顾问。亚搏官网app登录入口第12页共12页 Identification and Classification of Members of the Group. N/A Item 9. Notice of Dissolution of Group: N/A Item 10. Certification: By signing below I certify that to the best of my knowledge and belief, the securities referred to above were acquired in the ordinary course of business and were not acquired for the purpose of and do not have the effect of changing or influencing the control of the issuer of such securities and were not acquired in connection with or as a participant in any transaction having such purposes or effect. Signature After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct. Date: February 13, 2004 AXA FINANCIAL, INC.* /s/ Alvin H. Fenichel Alvin H. Fenichel Senior Vice President and Controller *Pursuant to the Joint Filing Agreement with respect to Schedule 13G attached hereto as Exhibit I, among AXA Financial, Inc., AXA Assurances I.A.R.D Mutuelle, AXA Assurances Vie Mutuelle, AXA Courtage Assurance Mutuelle, and AXA, this statement Schedule 13G is filed on behalf of each of them.