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                                                                    Exhibit 10.4


        VARIABLE RATE-SINGLE PAYMENT NOTE (Advancing-Optional Advances)

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AMOUNT            NOTE DATE            MATURITY DATE      TAX IDENTIFICATION #
$5,000,000.00     November 28, 2001    August 28, 2007    95-3535285
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On the Maturity Date, as stated above, for value received, the undersigned
promise(s) to pay to the order of COMERICA BANK-CALIFORNIA, ("Bank"), at any
office of the Bank in the State of CALIFORNIA,  FIVE MILLION and NO/100 Dollars
(U.S.) (or that portion of it advanced by the Bank and not repaid as later
provided) with interest until maturity, whether by acceleration or otherwise, or
until Default, as later defined, at a per annum rate equal to the Bank's base
rate from time to time in effect PLUS 0.000 % per annum and after that at a
default rate equal to the rate of interest otherwise prevailing under this Note
plus 3% per annum (but in no event in excess of the Maximum Rate). The Bank's
"base rate" is that annual rate of interest so designated by the Bank and which
is changed by the Bank from time to time. Interest rate changes will be
effective for interest computation purposes as and when the Bank's base rate
changes. Subject to the limitations hereinbelow set forth, interest shall be
calculated for the actual number of days the principal is outstanding on the
basis of a 360-day year if this Note evidences a business or commercial loan or
a 365-day year if a consumer loan. Accrued interest on this Note shall be
payable on (i) / / the Maturity Date or (ii) /X/ the 28TH day of each MONTH
commencing DECEMBER 28, 2001 until the Maturity Date when all amounts
outstanding under this Note shall be due and payable in full [check applicable
box]. If the frequency of interest payments is not otherwise specified, accrued
interest on this Note shall be payable monthly on the first day of each month.
If any payment of principal or interest under this Note shall be payable on a
day other than a day on which the Bank is open for business, this payment shall
be extended to the next succeeding business day and interest shall be payable at
the rate specified in this Note during this extension. A late payment charge
equal to a reasonable amount not to exceed 5% of each late payment may be
charged on any payment not received by the Bank within 10 calendar days after
the payment due date, but acceptance of payment of this charge shall not waive
any Default under this Note. Principal amounts advanced under this Note and
repaid may not be reborrowed.

The term "Maximum Rate," as used herein, shall mean at the particular time in
question the maximum nonusurious rate of interest which, under applicable law,
may then be charged on this Note. If such maximum rate of interest changes after
the date hereof, the Maximum Rate shall be automatically increased or decreased,
as the case may be, without notice to the undersigned from time to time as of
the effective date of each change in such maximum rate.

The principal amount payable under this Note shall be the sum of all advances
made by the Bank to or at the request of the undersigned, less principal
payments actually received in cash by the Bank. The books and records of the
Bank shall be the best evidence of the principal amount and the unpaid interest
amount owing at any time under this Note and shall be conclusive absent manifest
error. No interest shall accrue under this Note until the date of the first
advance made by the Bank; after that interest on all advances shall accrue and
be computed on the principal balance outstanding from time to time under this
Note until the same is paid in full. AT NO TIME SHALL THE BANK BE UNDER ANY
OBLIGATION TO MAKE ANY ADVANCES TO THE UNDERSIGNED PURSUANT TO THIS NOTE
(NOTWITHSTANDING ANYTHING EXPRESSED OR IMPLIED IN THIS NOTE OR ELSEWHERE TO THE
CONTRARY, INCLUDING WITHOUT LIMIT IF THE BANK SUPPLIES THE UNDERSIGNED WITH A
BORROWING FORMULA), AND THE BANK, AT ANY TIME AND FROM TIME TO TIME, WITHOUT
NOTICE, AND IN ITS SOLE DISCRETION, MAY REFUSE TO MAKE ADVANCES TO THE
UNDERSIGNED WITHOUT INCURRING ANY LIABILITY DUE TO THIS REFUSAL AND WITHOUT
AFFECTING THE UNDERSIGNED'S LIABILITY UNDER THIS NOTE FOR ANY AND ALL AMOUNTS
ADVANCED. The preceding sentence shall not apply to this Note if this Note is
secured by a deed of trust or mortgage covering real property.

This Note and any other indebtedness and liabilities of any kind of the
undersigned (or any of them) to the Bank, and any and all modifications,
renewals or extensions of it, whether joint or several, contingent or absolute,
now existing or later arising, and however evidenced and whether incurred
voluntarily or involuntarily, known or unknown, or originally payable to the
Bank or to a third party and subsequently acquired by Bank including, without
limitation, any late charges, loan fees or charges, overdraft indebtedness,
costs incurred by Bank in establishing, determining, continuing or defending the
validity or priority of any security interest, pledge or other lien or in
pursuing any of its rights or remedies under any loan document (or otherwise) or
in connection with any proceeding involving the Bank as a result of any
financial accommodation to the undersigned (or any of them), and reasonable
costs and expenses of attorneys and paralegals, whether inside or outside
counsel is used, and whether any suit or other action is instituted, and to
court costs if suit or action is instituted, and whether any such fees, costs or
expenses are incurred at the trial court level or on appeal, in bankruptcy, in
administrative proceedings, in probate proceedings or otherwise (collectively
"Indebtedness") are secured by and the Bank is granted a security interest in
and lien upon all items deposited in any account of any of the undersigned with
the Bank and by all proceeds of these items (cash or otherwise), all account
balances of any of the undersigned from time to time with the Bank, by all
property of any of the undersigned from time to time in the possession of the
Bank and by any other collateral, rights and properties described in each and
every deed of trust, mortgage, security agreement, pledge, assignment and other
security or collateral agreement which has been, or will at any time(s) later
be, executed by any (or all) of the undersigned to or for the benefit of the
Bank (collectively "Collateral"). Notwithstanding the above, (i) to the extent
that any portion of the Indebtedness is a consumer loan, that portion shall not
be secured by any deed of trust or mortgage on or other security interest in any
of the undersigned's principal dwelling or in any of the undersigned's real
property which is not a purchase money security interest as to that portion,
unless expressly provided to the contrary in another place, or (ii) if the
undersigned (or any of them) has (have) given or give(s) Bank a deed of trust or
mortgage covering real property, that deed of trust or mortgage shall not secure
this Note or any other indebtedness of the undersigned (or any of them), unless
expressly provided to the contrary in another place.

If the undersigned (or any of them) or any guarantor under a guaranty of all or
part of the Indebtedness ("guarantor") (i) fail(s) to pay this Note or any of
the Indebtedness when due, by maturity, acceleration or otherwise, or fail(s) to
pay any Indebtedness owing on a demand basis upon demand; or (ii) fail(s) to
comply with any of the terms or provisions of any agreement between the
undersigned (or any of them) or any guarantor and the Bank; or (iii) become(s)
insolvent or the subject of a voluntary or involuntary proceeding in bankruptcy,
or a reorganization, arrangement or creditor composition proceeding, (if a
business entity) cease(s) doing business as a going concern, (if a natural
person) die(s) or become(s) incompetent, (if a partnership) dissolve(s) or any
general partner of it dies, becomes incompetent or becomes the subject of a
bankruptcy proceeding or (if a corporation or a limited liability company) is
the subject of a dissolution, merger or consolidation; or (a) if any warranty or
representation made by any of the undersigned or any guarantor in connection
with this Note or any of the Indebtedness shall be discovered to be untrue or
incomplete; or (b) if there is any termination, notice of termination, or breach
of any guaranty, pledge, collateral assignment or subordination agreement
relating to all or any part of the Indebtedness; or (c) if there is any failure
by any of the undersigned or any guarantor to pay when due any of its
indebtedness (other than to the Bank) or in the observance or performance of any
term, covenant or condition in any document evidencing, securing or relating to
such indebtedness; or (d) if the Bank deems itself insecure believing that the
prospect of payment of this Note or any of the Indebtedness is impaired or shall
fear deterioration, removal or waste of any of the Collateral; or (e) if there
is filed or issued a levy or writ of attachment or garnishment or other like
judicial process upon the undersigned (or any of them) or any guarantor or any
of the Collateral, including, without limit, any accounts of the undersigned (or
any of them) or any guarantor with the Bank, then the Bank, upon the occurrence
of any of these events (each a "Default"), may at its option and without prior
notice to the undersigned (or any of them), declare any or all of the
Indebtedness to be immediately due and payable (notwithstanding any provisions
contained in the evidence of it to the contrary), cease advancing money or
extending credit to or for the benefit of the undersigned under this Note or any
other agreement between the undersigned (or any of them) and Bank, terminate
this Note as to any future liability or obligation of Bank, but without
affecting Bank's rights and security interests in any Collateral and the
Indebtedness of the undersigned (or any of them) to Bank, sell or liquidate all
or any portion of the Collateral, set off against the Indebtedness any amounts
owing by the Bank to the undersigned (or any of them), charge interest at the
default rate provided in the document evidencing the relevant Indebtedness and
exercise any one or more of the rights and remedies granted to the Bank by any
agreement with the undersigned (or any of them) or given to it under applicable
law. In addition, if this Note is secured by a deed of trust or mortgage
covering real property, then the trustor or mortgagor shall not mortgage or
pledge the mortgaged premises as security for any other indebtedness or
obligations. This Note, together with all other indebtedness secured by said
deed of trust or mortgage, shall become due and payable immediately, without
notice, at the option of the Bank, (a) if said trustor or mortgagor shall
mortgage or pledge the mortgaged premises for any other indebtedness or
obligations or shall convey, assign or transfer the mortgaged premises by deed,
installment sale contract or other instrument, or (b) if the title to the
mortgaged premises shall become vested in any other person or party in any
manner whatsoever, or (c) if there is any disposition (through one or more
transactions) of legal or beneficial title to a controlling interest of said
trustor or mortgagor. All payments under this Note shall be in immediately
available United States funds, without setoff or counterclaim.


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If this Note is signed by two or more parties (whether by all as makers or by
one or more as an accommodation party or otherwise), the obligations and
undertakings under this Note shall be that of all and any two or more jointly
and also of each severally. This Note shall bind the undersigned, and the
undersigned's respective heirs, personal representatives, successors and
assigns.

The undersigned waive(s) presentment, demand, protest, notice of dishonor,
notice of demand or intent to demand, notice of acceleration or intent to
accelerate, and all other notices, and agree(s) that no extension or indulgence
to the undersigned (or any of them) or release, substitution or nonenforcement
of any security, or release or substitution of any of the undersigned, any
guarantor or any other party, whether with or without notice, shall affect the
obligations of any of the undersigned. The undersigned waive(s) all defenses or
right to discharge available under Section 3-605 of the CALIFORNIA Uniform
Commercial Code and waive(s) all other suretyship defenses or right to
discharge. The undersigned agree(s) that the Bank has the right to sell, assign,
or grant participations or any interest in, any or all of the Indebtedness, and
that, in connection with this right, but without limiting its ability to make
other disclosures to the full extent allowable, the Bank may disclose all
documents and information which the Bank now or later has relating to the
undersigned or the Indebtedness. The undersigned agree(s) that the Bank may
provide information relating to this Note, the Indebtedness, or the undersigned
to the Bank's parent, affiliates, subsidiaries and service providers.

The undersigned agree(s) to reimburse the holder or owner of this Note upon
demand for any and all costs and expenses (including, without limit, court
costs, legal expenses and reasonable attorney fees, whether inside or outside
counsel is used, and whether or not suit is instituted and, if suit is
instituted, whether at the trial court level, appellate level, in a bankruptcy,
probate or administrative proceeding or otherwise) incurred in collecting or
attempting to collect this Note or incurred in any other matter or proceeding
relating to this Note.

The undersigned acknowledge(s) and agree(s) that there are no contrary
agreements, oral or written, establishing a term of this Note and agree(s) that
the terms and conditions of this Note may not be amended, waived or modified
except in a writing signed by an officer of the Bank expressly stating that the
writing constitutes an amendment, waiver or modification of the terms of this
Note. As used in this Note, the word "undersigned" means, individually and
collectively, each maker, accommodation party, indorser and other party signing
this Note in a similar capacity. If any provision of this Note is unenforceable
in whole or part for any reason, the remaining provisions shall continue to be
effective. THIS NOTE IS MADE IN THE STATE OF CALIFORNIA AND SHALL BE GOVERNED BY
AND CONSTRUED IN ACCORDANCE WITH THE INTERNAL LAWS OF THE STATE OF CALIFORNIA,
WITHOUT REGARD TO CONFLICT OF LAWS PRINCIPLES.

The maximum interest rate shall not exceed the highest applicable usery ceiling

THE UNDERSIGNED, BY ACCEPTANCE OF THIS NOTE, AND THE BANK ACKNOWLEDGE THAT THE
RIGHT TO TRIAL BY JURY IS A CONSTITUTIONAL ONE, BUT THAT IT MAY BE WAIVED. EACH
PARTY, AFTER CONSULTING (OR HAVING HAD THE OPPORTUNITY TO CONSULT) WITH COUNSEL
OF THEIR CHOICE, KNOWINGLY AND VOLUNTARILY, AND FOR THEIR MUTUAL BENEFIT, WAIVES
ANY RIGHT TO TRIAL BY JURY IN THE EVENT OF LITIGATION REGARDING THE PERFORMANCE
OR ENFORCEMENT OF, OR IN ANY WAY RELATED TO, THIS NOTE OR THE INDEBTEDNESS.

1)       This Note is subject to the provisions of the Business Loan Agreement
         dated November 28, 2001, and all amendments thereto and replacements
         therefor.

2)       See Addendum "A" attached hereto and made a part hereof.

INITIAL HERE _______

Overland Data, Inc.

By:  /s/ Christopher Calisi                       Its:   President & CEO
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    SIGNATURE OF                                      TITLE

By:  /s/ Vernon A. LoForti                        Its:   VP & CFO
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By:                                               Its:
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By:                                               Its:
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8975 Balboa Ave.          San Diego     California     USA            92123
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STREET ADDRESS            CITY          STATE          COUNTRY        ZIP CODE


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                                  ADDENDUM "A"

                  ADDENDUM TO VARIABLE RATE-SINGLE PAYMENT NOTE
                          (ADVANCING-OPTIONAL ADVANCES)

         This Addendum to Variable Rate-Single Payment Note (Advancing-Optional
Advances) dated November 28, 2001 (this "Addendum") is attached to, and by this
reference shall be a part of and is hereby incorporated by this reference into
that certain Variable Rate-Single Payment Note (Advancing-Optional Advances)
dated November 28, 2001 (the "Note") executed by Overland Data, Inc.
("Borrower") in favor of Comerica Bank-California ("Bank"). All initially
capitalized terms used but not defined in this Addendum shall have the meanings
assigned to such terms in the Note. Borrower hereby agrees that the following
terms and conditions shall be incorporated into the Note:

         1)       Subject to the terms and conditions set forth in the Note,
                  advances under the Note shall be available from the date
                  hereof through August 28, 2002 (the "Draw Period"). During the
                  Draw Period, interest shall be payable as set forth in the
                  Note. Upon expiration of the Draw Period, all amounts
                  outstanding under the Note shall be payable on the 28th day of
                  each month, beginning on September 28, 2002, on the basis of
                  an amortization of 60 equal payments of principal plus accrued
                  interest thereon. All unpaid principal and accrued but unpaid
                  interest shall in any event be due and payable on or before
                  the Maturity Date set forth in the Note.

         2)       The Borrower agrees that each request for an advance hereunder
                  shall be in writing, duly executed by Borrower in form
                  satisfactory to Bank, and shall be irrevocable upon receipt by
                  Bank. The notice shall include a copy of the invoice for the
                  equipment or tenant improvement to be financed.