EXHIBIT 10.21
                                                   -------------

 
                                                                   EXHIBIT 10.21
 
                           CONNER PERIPHERALS, INC.
                   Note Agreement dated as of March 29, 1991
             $80,000,000 Series A Senior Notes Due March 30, 1996 
             $25,000,000 Series B Senior Notes Due March 30, 1998

                       SIXTH AMENDMENT TO NOTE AGREEMENT

                         Dated as of October 31, 1994

     1.   Reference is made to those certain separate note agreements
(collectively, the "Note Agreements") dated as of March 29, 1991, between each
of the persons listed as "Purchasers" on Annex 1 thereto and Conner Peripherals,
Inc. (the "Company"), executed in connection with the issuance by the Company of
its 8.84% Series A Senior Notes due March 30, 1996, and its 9.08% Series B
Senior Notes due March 30, 1998 (the "Notes"), as amended and restated by that
certain Fifth Amendment to Note Agreement, dated as of December 22, 1993.  All
capitalized terms not defined herein have the meanings specified in the Note
Agreements.

     2.   The parties hereto agree that paragraph 6M of the Note Agreements is
amended to read in full as follows:

          6M.  SUBORDINATED DEBT.  The Company will not, and will not permit any
     Restricted Subsidiary to, make any payment or redemption of Subordinated
     Debt, other than mandatory prepayments or mandatory redemptions scheduled
     at the time of issuance of such Subordinated Debt, or otherwise purchase or
     acquire any Subordinated Debt, directly or indirectly, or give any notice
     that irrevocably binds it to take any such action, unless:

               (i)  no Default or Event of Default shall exist immediately prior
          to, or immediately after, the consummation of any such action or the
          giving of such notice, whichever shall first occur, and the Company
          has delivered a certificate to such effect to each holder of Notes
          prior to, but not more than 30 days prior to, taking such action or
          giving such notice, whichever shall first occur, together with a brief
          description of such action or the action contemplated by such notice;
          and

               (ii) at the time it shall become irrevocably bound to take such
          action, or the time it shall take such action, whichever shall first
          occur, one of the following conditions shall be satisfied:

                         (a) the Company or such Restricted Subsidiary, as the
               case may be, could incur Senior Debt in an amount equal to the
               amount of Subordinated Debt to be so prepaid, redeemed or
               otherwise purchased or acquired;

                         (b) the Subordinated Debt to be so prepaid, redeemed or
               otherwise purchased or acquired is convertible into a number of
               shares of capital stock of the Company having a Fair Market Value
               at the time that the Company or such Restricted Subsidiary
               becomes obligated to take such action which is at least 25% in
               excess of the principal amount of such Subordinated Debt; or

                         (c) the Subordinated Debt to be so prepaid, redeemed or
               otherwise purchased or acquired is convertible into a number of
               shares of capital stock of the Company having a Fair Market Value
               at the time that the Company or such Restricted Subsidiary
               becomes obligated to take such action which is a least 15% in
               excess of the principal amount of such Subordinated Debt, and the
               Company has entered into a firm commitment underwriting agreement
               with one or more underwriters, which agreement contains terms and
               conditions no less favorable to the Company than those generally
               included in comparable agreements for similarly situated issuers
               at such time (as determined by the Company in its reasonable
               judgment), and pursuant to which such underwriters have agreed to
               purchase capital stock of the Company for an amount sufficient to
               prepay, redeem or otherwise purchase or acquire all or any part
               of such Subordinated Debt that is not so converted into such
               capital stock prior to such prepayment, redemption, purchase or
               acquisition;

 
                                                        CONNER PERIPHERALS, INC.
                                               SIXTH AMENDMENT TO NOTE AGREEMENT
                                                                OCTOBER 31, 1994

     provided that no such action shall be taken and no such notice given during
     the period beginning on October 3, 1993 and ending on the Determination
     Date occurring nearest to March 31, 1995, inclusive.

          Nothing set forth in this paragraph 2 shall prevent the Company or
     any Restricted Subsidiary from purchasing or acquiring any Subordinated
     Debt in privately negotiated transactions or in open-market transactions
     if:

               (1) the price paid is less than par plus accrued interest;

               (2) no Default or Event of Default shall exist immediately prior
          to, or immediately after, such purchase or acquisition; and

               (3) the aggregate amount of purchases or acquisitions shall
          not exceed an amount equal to $50 million.

     3.   The parties hereto agree that paragraph 6O of the Note Agreements
is amended to read in full as follows:

          6O.  RESTRICTED PAYMENTS.  The Company shall not make any
     Restricted Payments during the period beginning on October 3, 1993 and
     ending on the Determination Date occurring nearest to March 31, 1995,
     inclusive, provided that the foregoing prohibition shall not apply to

               (i)     repurchases of Subordinated Debt to the extent permitted
          by paragraph 6M hereof, and

              (ii)     repurchases by the Company of rights to purchase the
          common stock of the Company, which rights were issued in connection
          with that certain Stockholders Rights Plan adopted by the Company on
          October 18, 1994 as in effect as initially adopted by the Company (a
          certified copy of the form of which to be adopted has been delivered
          to the holders of the Notes), so long as the aggregate amount of such
          repurchases does not exceed $1 million.

     4.   The Company warrants and represents that

          (a) immediately prior to the effectiveness of this Amendment, and
     immediately after the effectiveness of this Amendment, no Default or Event
     of Default has occurred and is continuing,

          (b) all consents, notices, approvals, waivers, and other actions by
     other holders of Debt of the Company or any Subsidiary that are necessary
     in connection with the subject matter of this Amendment have been obtained,
     and

          (c) attached hereto is a true and correct copy of the Stockholders
     Rights Plan Agreement in the form to be initially adopted by the Company.

     5.   Each reference in each Note Agreement to the "Agreement," this
"Agreement," "hereunder," and "hereof" shall mean such Note Agreement as amended
hereby. This Amendment shall bind and inure to the benefit of the respective
successors and permitted assigns of the parties to Note Agreement (including,
without limitation, any Permitted Transferee).

     6.   No other term or provision of the Note Agreements or the Notes, or
right or remedy consequent thereon, shall be amended, waived or affected by this
Amendment.  This Amendment constitutes the final written expression of all of
the terms hereof and is a complete and exclusive statement of those terms.

     7.   This Amendment shall be construed and enforced in accordance with, and
the rights of the parties shall be governed by, the law of the State of New
York.

                                       2

 
                                                        CONNER PERIPHERALS, INC.
                                               SIXTH AMENDMENT TO NOTE AGREEMENT
                                                                OCTOBER 31, 1994

     8.   Two or more duplicate originals hereof may be signed by the parties
hereto, each of which shall be an original but all of which together shall
constitute one and the same instrument.  This Amendment may be executed in one
or more counterparts and each set of counterparts that, collectively, show
execution by each party hereto shall constitute one duplicate original.

     9.   This Amendment shall take effect upon date (the "Effective Date")on
which each of the following conditions shall be satisfied (but this Amendment
shall be of no force or effect if such date is not on or prior to November 30,
1994);

          (a) Evidence of execution of this Amendment shall have been provided
     by each of the holders of Notes constituting the Required Holders and the
     Company, by delivering an original of, or original signature page to, this
     Amendment showing manual execution of this Amendment by an authorized
     officer or authorized officers of such person by facsimile transmission or
     by overnight courier, addressed to Hebb & Gitlin, One State Street,
     Hartford, CT 06103, Telecopier Number (203) 278-8968, Attn: Thomas J. Love,
     Jr.;

          (b) The Company shall have paid any statement for reasonable fees and
     disbursements of Hebb & Gitlin, the special counsel to the holders of the
     Notes, presented on or prior to the Effective Date, incurred in connection
     with the preparation and execution hereof; and

          (c) All warranties and representations made herein by the Company
     shall be true on the Effective Date.

          [Remainder of page intentionally blank.  Next page is signature page.]

                                       3

 
                                                        CONNER PERIPHERALS, INC.
                                               SIXTH AMENDMENT TO NOTE AGREEMENT
                                                                OCTOBER 31, 1994

                                            CONNER PERIPHERALS, INC.



                                    By          /s/ P. Jackson Bell
                                             -----------------------------------

                                    Name: P. Jackson Bell

                                    Title:      Executive Vice President and
                                                Chief Financial Officer

                                    By          /s/ James A. Taylor
                                             -----------------------------------

                                    Name: James A. Taylor

                                    Title:      Vice President and Treasurer










[Signature page to Sixth Amendment dated as of October 31, 1994, to Note 
Agreement dated as of March 29, 1991 of Conner Peripherals, Inc.]



 
                                                        CONNER PERIPHERALS, INC.
                                               SIXTH AMENDMENT TO NOTE AGREEMENT
                                                                OCTOBER 31, 1994

THE PRUDENTIAL INSURANCE COMPANY OF AMERICA



By:       /s/ Raymond G. Kennedy
   ----------------------------------

Name: Raymond G. Kennedy

Title:    Second Vice President










[Signature page to Sixth Amendment dated as of October 31, 1994, to Note 
Agreement dated as of March 29, 1991 of Conner Peripherals, Inc.]



 
                                                        CONNER PERIPHERALS, INC.
                                               SIXTH AMENDMENT TO NOTE AGREEMENT
                                                                OCTOBER 31, 1994

CIG & CO.
C/O CIGNA INVESTMENTS, INC.



By:       /s/ Edward Lewis
   ----------------------------------

Name: Edward Lewis

Title:    Partner










[Signature page to Sixth Amendment dated as of October 31, 1994, to Note 
Agreement dated as of March 29, 1991 of Conner Peripherals, Inc.]



 
                                                        CONNER PERIPHERALS, INC.
                                               SIXTH AMENDMENT TO NOTE AGREEMENT
                                                                OCTOBER 31, 1994

PRINCIPAL MUTUAL LIFE INSURANCE COMPANY



By:       /s/ Donald D. Brattebo
   -----------------------------------

Name: Donald D. Brattebo

Title:    Second Vice President - Securities Investment



By:       /s/ Christopher J. Henderson
   -----------------------------------

Name: Christopher J. Henderson

Title:    Counsel










[Signature page to Sixth Amendment dated as of October 31, 1994, to Note 
Agreement dated as of March 29, 1991 of Conner Peripherals, Inc.]



 
                                                        CONNER PERIPHERALS, INC.
                                               SIXTH AMENDMENT TO NOTE AGREEMENT
                                                                OCTOBER 31, 1994

GENERAL AMERICAN LIFE INSURANCE COMPANY



By:__________________________________

Name:

Title:











[Signature page to Sixth Amendment dated as of October 31, 1994, to Note 
Agreement dated as of March 29, 1991 of Conner Peripherals, Inc.]