Exhibit 10.4



                               QUANTUM CORPORATION

                      MICHAEL A. BROWN SEPARATION AGREEMENT

     This Agreement is made by and between Quantum Corporation, a Delaware
Corporation ("the Company"), and you, Michael A. Brown, as of September 3, 2002
(the "Effective Date").

     This Agreement is intended to provide you with certain separation benefits
in recognition of your past services with the Company should your employment
with the Company terminate under certain circumstances, to provide you with
enhanced financial security and sufficient incentive and encouragement to remain
with the Company.

     1.   Separation Benefits. Subject to your compliance with Section 3 and
your entering into and not revoking a release of claims with the Company (in the
form provided by the Company), in the event your employment is terminated, you
will be entitled to the following benefits:

          (a)   Involuntary Termination.

                (i)      Involuntary Termination During the Employment Term. If
your employment terminates as a result of an "Involuntary Termination" (as
defined below) during the Employment Term (as defined in your Employment
Agreement dated as of September 3, 2002 (your "Employment Agreement")), then you
will be entitled to the following:

                         (1) Separation Payment. You will be entitled to the
remaining payments of any unpaid Base Salary (as defined in your Employment
Agreement) with respect to the remainder of the Employment Term, payable in a
lump sum as soon as administratively feasible after your termination date.

                         (2)  Other Benefits. To the extent eligible on the date
of termination, you will be permitted to continue participation, at no
additional after-tax cost than you would have as an employee in the Company's
health, life insurance and disability plans until September 2, 2003. To the
extent such coverage cannot be provided under the Company's benefit plans
without jeopardizing the tax status of such plans or for underwriting reasons,
the Company shall pay you an amount such that you can purchase such benefits
separately at no greater after-tax cost to you than you would have had if the
benefits were provided to you as an employee.

                         (3)  Accrued Benefits. The Company will pay you: (1)
any unpaid Base Salary due for periods prior to the date of your employment
termination, (2) any unpaid portion of your Separation Transition Award (as
defined in your Employment Agreement) that becomes payable on January 1, 2003
pursuant to your Employment Agreement, (3) all of your accrued and unused
vacation through the date of your employment termination, (4) following your
submission of proper expense reports, the total unreimbursed amount of all
expenses that you reasonably and necessarily incurred in connection with the
business of the Company prior to the date of your employment termination, and
(5) such other compensation or benefits from the Company as may be


required by law (collectively, the "Accrued Benefits"). These payments will be
made promptly upon your employment termination and within the period of time
mandated by law; provided, however, that any unpaid portion of your Separation
Transition Award that becomes payable on January 1, 2003 pursuant to your
Employment Agreement will be paid on or about that date.

          (b)   Termination for Cause; Other Termination. If (1) the Company
terminates your employment at any time for "Cause" (as defined below), or (2)
you voluntarily terminate your employment for any reason, then the Company will
pay you the Accrued Benefits. These payments will be made promptly upon your
employment termination and within the period of time mandated by law; provided,
however, that any unpaid portion of your Separation Transition Award that
becomes payable on January 1, 2003 pursuant to your Employment Agreement will be
paid on or about that date.

     2.   Golden Parachute Excise Tax.

          (a)   Excise Tax Gross-Up. In the event that any payment or benefit
provided for in this Agreement or otherwise payable to you, but determined
without regard to any additional payment required under this Section 2
(collectively, the "Separation Payments"), would (i) constitute a "parachute
payment" within the meaning of Section 280G of the Internal Revenue Code of
1986, as amended (the "Code"), or any similar or successor provision to 280G,
and (ii) be subject to the excise tax imposed by Section 4999 of the Code or any
similar or successor provision to Section 4999, or any interest or penalties
payable with respect to such excise tax (such excise tax, together with any such
interest and penalties, are hereinafter collectively referred to as the "Excise
Tax"), then you shall be entitled to receive from the Company an additional
payment (the "Gross-Up Payment") in an amount such that after your payment of
all taxes (including any Excise Tax) imposed upon the Gross-Up Payment, you
retain an amount of the Gross-Up Payment equal to the Excise Tax imposed upon
the Separation Payments. For purposes of determining the amount of the Gross-Up
Payment, you shall be deemed to (i) pay federal income taxes at the highest
marginal rates of federal income taxation for the calendar year in which the
Gross-Up Payment is to be made, and (ii) pay applicable state and local income
taxes at the highest marginal rate of taxation for the calendar year in which
the Gross-Up Payment is to be made, net of the maximum reduction in federal
income taxes which could be obtained from deduction of such state and local
taxes.

          (b)   Determination of Amount. Subject to the provisions of this
Section 2(b), all determinations required to be made under Section 2(a),
including whether and when a Gross-Up Payment is required, the amount of such
Gross-Up Payment and the assumptions to be utilized in arriving at such
determinations, shall be made by the public accounting firm that is engaged by
the Company for general audit purposes as of the date immediately prior to the
Change of Control (the "Accounting Firm"). In the event that the Accounting Firm
is serving as accountant or auditor for the individual, entity or group
effecting the Change of Control, the Company shall appoint another nationally
recognized public accounting firm to make the determinations required hereunder
(which accounting firm shall then be referred to as the Accounting Firm
hereunder). The Company shall bear all expenses with respect to the
determinations by the Accounting Firm required to be made hereunder. Any good
faith determinations of the Accounting Firm made hereunder shall be final,
binding and conclusive upon the Company and the Employee. As a result of the
uncertainty in the application of Section 4999 of the Code at the time of the
determination by the Accounting Firm, it

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is possible that Gross-Up Payments which will not have been made by the Company
should have been made ("Underpayment") or Gross-Up Payments are made by the
Company which should not have been made ("Overpayment"), consistent with the
calculations required to be made hereunder. In the event that you thereafter are
required to make payment of any Excise Tax or additional Excise Tax, the
Accounting Firm shall determine the amount of the Underpayment that has occurred
and any such Underpayment (together with interest, to the extent not already
within the Excise Tax, at the rate provided in Section 1274(b)(2)(B) of the
Code) shall be promptly paid by the Company to or for your benefit. In the event
the amount of the Gross-Up Payment exceeds the amount necessary to reimburse you
for your Excise Tax, the Accounting Firm shall determine the amount of the
Overpayment that has been made and any such Overpayment (together with interest
at the rate provided in Section 1274(b)(2) of the Code) shall be promptly paid
by you (to the extent you have received a refund if the applicable Excise Tax
has been paid to the Internal Revenue Service) to or for the benefit of the
Company. You shall cooperate, to the extent your expenses are reimbursed by the
Company, with any reasonable requests by the Company in connection with any
contests or disputes with the Internal Revenue Service in connection with the
Excise Tax.

     3.   Non-Compete; Non-Solicit; Non-Disparagement.

          (a)   General. The parties to this Agreement recognize that your
services are special and unique and that the level of compensation and the
provisions herein for compensation after termination are partly in consideration
of and conditioned upon your not competing with the Company, and that your
covenant not to compete or solicit as set forth in this Section 3 during and
after employment is essential to protect the business and goodwill of the
Company.

          (b)   Noncompetition. You agree that commencing upon your termination
of employment and until September 2, 2005 (the "Covenant Period"), you will not
either directly or indirectly, whether as a director, officer, consultant,
employee or advisor or in any other capacity engage in or have any ownership
interest in or participate in the financing, operation, management or control
of, any person, firm, corporation or business that "competes" with Company or is
a customer or client of the Company; provided, however, that it will not be a
violation of this Section 3 for you to acquire an investment not more than one
(1) percent of the capital stock of a competing business, whose stock is traded
on a national securities exchange or through the automated quotation system of a
registered securities association. "Competes" shall be defined as competing
directly in Quantum's tape drive, tape automation or data protection systems
businesses, along with any other businesses Quantum may be directly engaged in
on the date of the later to occur of: i) the termination of your employment; or
ii) the termination of your status as a member of Quantum's Board of Directors.
Examples of such competitors would include Storage Technology, ADIC, Seagate and
Sony. Competes shall not be defined broadly to mean any storage business. For
purposes of this Section 3, the term "Company" shall mean and include the
Company, any subsidiary or affiliate of the Company, any successor to the
business of the Company (by merger, consolidation, sale of assets or stock or
otherwise) and any other corporation or entity in which you may serve as a
director, officer or employee at the request of the Company or any successor of
the Company.

          (c)   Nonsolicitation. During the Covenant Period, you will not,
directly or indirectly, induce or attempt to influence any employee of the
Company to leave its employ.

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          (d)   Nondisparagement. During the Covenant Period, you will not,
directly or indirectly, disparage, impugn or make any derogatory public
statements regarding the Company and/or its officers, directors or former or
current employees.

          (e)   Injunctive Relief. You agree that the Company would suffer an
irreparable injury if you were to breach the covenants contained in Sections
3(b), (c) or (d) and that the Company would by reason of such breach or
threatened breach be entitled to injunctive relief in a court of appropriate
jurisdiction and you hereby consent to the entering of such injunctive relief
prohibiting you from engaging in such breach.

          (f)   Scope of Restrictions. If any of the restrictions contained in
this Section 3 shall be deemed to be unenforceable by reason of the extent,
duration or geographical scope or other provisions thereof, then the parties
hereto contemplate that the court shall reduce such extent, duration,
geographical scope or other provision hereof and enforce this Section 3 in its
reduced form for all purposes in the manner contemplated hereby.

          (g)   Effect on Payments and Benefits. You agree that should you
violate the terms of this Section 3, you are not entitled to any of the Base
Salary or benefits set forth in Section 1 and remaining to be paid.

     4.   Definitions. The following terms referred to in this Agreement shall
have the following meanings:

          (a)   Cause. "Cause" shall mean:

                 (i)     Any act of personal dishonesty taken by you in
connection with your responsibilities as an employee that is intended to result
in your substantial personal enrichment;

                 (ii)    Your conviction of a felony;

                 (iii)   A willful act by you which constitutes gross misconduct
injurious to the Company; or

                 (iv)    Continued violations of your obligations to the Company
under the Company's established personnel policies and procedures which are
demonstrably willful and deliberate on your part after the Company has delivered
to you a written demand for performance that describes the basis for the
Company's belief that you have not substantially performed your duties.

          (b)   Change of Control. "Change of Control" shall mean the occurrence
of any of the following events:

                 (i)     Any "person" (as such term is used in Sections 13(d)
and 14(d) of the Securities Exchange Act of 1934, as amended) is or becomes the
"beneficial owner" (as defined in Rule 13d-3 under said Act), directly or
indirectly, of securities of the Company representing forty percent (40%) or
more of the total voting power represented by the Company's then outstanding
voting securities;

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                 (ii)    A change in the composition of the Board occurring
within a six (6) month period, as a result of which fewer than a majority of the
directors are Incumbent Directors. "Incumbent Directors" shall mean directors
who either (A) are directors of the Company as of the date hereof, or (B) are
elected, or nominated for election, to the board of directors of the Company
with the affirmative votes of at least a majority of the Incumbent Directors at
the time of such election or nomination (but shall not include an individual
whose election or nomination is in connection with an actual or threatened proxy
contest relating to the election of directors to the Company); or

                 (iii)   The stockholders of the Company approve a merger or
consolidation of the Company with any other corporation, other than a merger or
consolidation which would result in the voting securities of the Company
outstanding immediately prior thereto continuing to represent (either by
remaining outstanding or by being converted into voting securities of the
surviving entity) at least fifty percent (50%) of the total voting power
represented by the voting securities of the Company or such surviving entity
outstanding immediately after such merger or consolidation, or the stockholders
of the Company approve a plan of complete liquidation of the Company or an
agreement for the sale or disposition by the Company of all or substantially all
of the Company's assets.

          (c)   Disability. "Disability" shall mean that you have been unable to
perform your duties under this Agreement as the result of your incapacity due to
physical or mental illness with or without reasonable accommodation, and such
inability, at least twenty six (26) weeks after its commencement, is determined
to be total and permanent by a physician selected by the Company or its insurers
and acceptable to you or your legal representative (such statement as to
acceptability not to be unreasonably withheld). Termination resulting from
Disability may only be effected after at least thirty (30) days' written notice
by the Company of its intention to terminate your employment. In the event that
you resume the performance of substantially all your duties hereunder before the
termination of your employment becomes effective, the notice of intent to
terminate shall automatically be deemed to have been revoked.

          (d)   Involuntary Termination. "Involuntary Termination" shall mean:

                 (i)     Without your express written consent, the assignment to
you of any duties or the reduction of your duties, either of which results in a
significant diminution in your position or responsibilities with the Company in
effect immediately prior to such assignment, or your removal from such position
and responsibilities (other than an assignment to Vice-Chairman, as contemplated
by Section 1(a) of your Employment Agreement);

                 (ii)    Without your express written consent, a substantial
reduction of the facilities and perquisites (including office space and
location) available to you immediately prior to such reduction;

                 (iii)   A reduction by the Company in your Base Salary as in
effect immediately prior to such reduction;

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                 (iv)    A material reduction by the Company in the kind or
level of employee benefits to which you are entitled immediately prior to such
reduction with the result that the Employee's overall benefits package is
significantly reduced;

                 (v)     Your relocation to a facility or relocation more than
twenty five (25) miles from your then present location without your express
written consent;

                 (vi)    Any purported termination of your employment by the
Company which is not effected for Cause;

                 (vii)   Your termination of employment due to death or
Disability; or

                 (viii)  The failure of the Company to obtain the assumption of
this Agreement by any successors contemplated in Section 5 below.

     5.   Assignment. This Agreement will be binding upon and inure to the
benefit of (a) your heirs, executors and legal representatives upon your death,
and (b) any successor of the Company. Any such successor of the Company will be
deemed substituted for the Company under the terms of this Agreement for all
purposes. For this purpose, "successor" means any person, firm, corporation or
other business entity which at any time, whether by purchase, merger or
otherwise, directly or indirectly acquires all or substantially all of the
assets or business of the Company. None of your rights to receive any form of
compensation payable pursuant to this Agreement may be assigned or transferred
except by will or the laws of descent and distribution. Any other attempted
assignment, transfer, conveyance or other disposition of your right to
compensation or other benefits will be null and void.

     6.   Notices. All notices, requests, demands and other communications
called for hereunder shall be in writing and shall be deemed given (i) on the
date of delivery if delivered personally, (ii) one (1) day after being sent by a
well-established commercial overnight service, or (iii) four (4) days after
being mailed by registered or certified mail, return receipt requested, prepaid
and addressed to the parties or their successors at the following addresses, or
at such other addresses as the parties may later designate in writing:

     If to the Company:

     Quantum Corporation
     501 Sycamore Drive
     Milpitas, California 95035
     Attn: General Counsel

     If to you:

     at the last residential address known by the Company.

     7.   Severability. In the event that any provision hereof becomes or is
declared by a court of competent jurisdiction to be illegal, unenforceable or
void, this Agreement will continue in full force and effect without said
provision.

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     8.   Entire Agreement. This Agreement, including the Employment Agreement,
the Employee Agreement dated July 23, 1982 and your option and restricted stock
agreements (except as modified herein), represents the entire agreement and
understanding between you and Company concerning your employment relationship
with the Company, and supersedes and replaces any and all prior agreements and
understandings concerning your employment relationship with the Company,
including, but not limited to, your Chief Executive Officer Change of Control
Agreement with the Company dated April 1, 2001 (the "Change of Control
Agreement").

     9.   Arbitration.

          (a)   General. In consideration of your service to the Company, its
promise to arbitrate all employment related disputes your receipt of the
compensation, pay raises and other benefits paid to you by the Company, at
present and in the future, you agree that any and all controversies, claims, or
disputes with anyone (including the Company and any employee, officer, director,
shareholder or benefit plan of the Company in their capacity as such or
otherwise) arising out of, relating to, or resulting from your service to the
Company under this Agreement or otherwise or the termination of your service
with the Company, including any breach of this Agreement, shall be subject to
binding arbitration under the Arbitration Rules set forth in California Code of
Civil Procedure Section 1280 through 1294.2, including Section 1283.05 (the
"Rules") and pursuant to California law. Disputes which you agree to arbitrate,
and thereby agree to waive any right to a trial by jury, include any statutory
claims under state or federal law, including, but not limited to, claims under
Title VII of the Civil Rights Act of 1964, the Americans with Disabilities Act
of 1990, the Age Discrimination in Employment Act of 1967, the Older Workers
Benefit Protection Act, the California Fair Employment and Housing Act, the
California Labor Code, claims of harassment, discrimination or wrongful
termination and any statutory claims. You further understand that this Agreement
to arbitrate also applies to any disputes that the Company may have with you.


          (b)   Procedure. You agree that any arbitration will be administered
by the American Arbitration Association ("AAA") and that a neutral arbitrator
will be selected in a manner consistent with its National Rules for the
Resolution of Employment Disputes. The arbitration proceedings will allow for
discovery according to the rules set forth in the National Rules for the
Resolution of Employment Disputes or California Code of Civil Procedure. You
agree that the arbitrator shall have the power to decide any motions brought by
any party to the arbitration, including motions for summary judgment and/or
adjudication and motions to dismiss and demurrers, prior to any arbitration
hearing. You agree that the arbitrator shall issue a written decision on the
merits. You also agree that the arbitrator shall have the power to award any
remedies, including attorneys' fees and costs, available under applicable law.
You understand the Company will pay for any administrative or hearing fees
charged by the arbitrator or AAA except that you shall pay the first $200.00 of
any filing fees associated with any arbitration you initiate. You agree that the
arbitrator shall administer and conduct any arbitration in a manner consistent
with the Rules and that to the extent that the AAA's National Rules for the
Resolution of Employment Disputes conflict with the Rules, the Rules shall take
precedence.

          (c)   Remedy. Except as provided by the Rules, arbitration shall be
the sole, exclusive and final remedy for any dispute between you and the
Company. Accordingly, except as provided for by the Rules, neither you nor the
Company will be permitted to pursue court action

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regarding claims that are subject to arbitration. Notwithstanding, the
arbitrator will not have the authority to disregard or refuse to enforce any
lawful Company policy, and the arbitrator shall not order or require the Company
to adopt a policy not otherwise required by law which the Company has not
adopted.

          (d)   Availability of Injunctive Relief. In addition to the right
under the Rules to petition the court for provisional relief, you agree that any
party may also petition the court for injunctive relief where either party
alleges or claims a violation of this Agreement or the Confidentiality Agreement
or any other agreement regarding trade secrets, confidential information,
nonsolicitation or Labor Code (S) 2870. In the event either party seeks
injunctive relief, the prevailing party shall be entitled to recover reasonable
costs and attorneys' fees.

          (e)   Administrative Relief. You understand that this Agreement does
not prohibit you from pursuing an administrative claim with a local, state or
federal administrative body such as the Department of Fair Employment and
Housing, the Equal Employment Opportunity Commission or the workers'
compensation board. This Agreement does, however, preclude you from pursuing
court action regarding any such claim.

          (f)   Voluntary Nature of Agreement. You acknowledge and agree that
you are executing this Agreement voluntarily and without any duress or undue
influence by the Company or anyone else. You further acknowledge and agree that
you have carefully read this Agreement and that you have asked any questions
needed for you to understand the terms, consequences and binding effect of this
Agreement and fully understand it, including that you are waiving your right to
a jury trial. Finally, you agree that you have been provided an opportunity to
seek the advice of an attorney of your choice before signing this Agreement.

     10.  No Oral Modification, Cancellation or Discharge. This Agreement may be
changed or terminated only in writing (signed by you and the Company).

     11.  Withholding. The Company is authorized to withhold, or cause to be
withheld, from any payment or benefit under this Agreement the full amount of
any applicable withholding taxes.

     12.  Governing Law. This Agreement will be governed by the laws of the
State of California (with the exception of its conflict of laws provisions).

     13.  Involuntary Termination Definition. You hereby agree that the
transactions with Maxtor Corporation ("Maxtor") pursuant to the Amended and
Restated Agreement and Plan of Merger and Reorganization, dated as of October 3,
2000 (the "Merger Agreement"), by and among the Company, Insula Corporation
("Insula"), and Maxtor or the new terms of your employment with the Company
pursuant to the Employment Agreement and this Agreement (including, but not
limited to, the change in your title and any change in your authorities, duties
and responsibilities with the Company) do not constitute an "Involuntary
Termination" under this Agreement or your Change of Control Agreement.

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     14.  Acknowledgment. You acknowledge that you have had the opportunity to
discuss this matter with and obtain advice from your private attorney, have had
sufficient time to, and have carefully read and fully understand all the
provisions of this Agreement, and are knowingly and voluntarily entering into
this Agreement.

     IN WITNESS WHEREOF, the undersigned have executed this Agreement on the
respective dates set forth below:

     MICHAEL A. BROWN



      /s/ Michael A. Brown                            Date: October 22, 2002
     ---------------------------
     Michael A. Brown



     QUANTUM CORPORATION



      /s/ Gregory W. Slayton                          Date: October 24, 2002
     ---------------------------
     Name:  Gregory W. Slayton
     Title: Chairman, Compensation Committee

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