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                                                                   EXHIBIT 10.22

                               FOURTH AMENDMENT TO
                                CREDIT AGREEMENT

      This Fourth Amendment to Credit Agreement is entered into as of this
27th day of June, 2000, and made effective as of January 1, 2000, by and
between COMERICA BANK, a Michigan banking corporation ("Bank"), with offices
at One Detroit Center, 500 Woodward Avenue, Detroit, Michigan 48226 and
SIMPLE TECHNOLOGY, INC., a California corporation ("Company"), whose
principal office is located at 3001 Daimler Street, Santa Ana, CA 92705.

                                    RECITALS:

      A.    Bank and Company entered into a certain Credit Agreement dated as of
August 3, 1999 as amended by a First Amendment to Credit Agreement, a Second
Amendment to Credit Agreement and a Third Amendment to Credit Agreement (the
"Agreement"),

      B.    The parties desire to further amend the Agreement, upon the
following terms and conditions.

      NOW THEREFORE, for good and valuable consideration, the parties agree as
follows:

      1.    The following new definition shall be inserted immediately after the
definition of "Collateral" on Page 3 of the Agreement:

            " `CORPORATE TAX LIABILITY' shall mean income tax liability of the
      Borrower's shareholders relating to salaries, wages and bonuses paid by
      Borrower to its shareholders and corporate income of Borrower taxable to
      its shareholders as a result of Borrower's Subchapter S election. For this
      purpose, it shall be assumed that income recognized by the shareholders of
      Borrower as a result of Borrower's election to be taxed as an S
      corporation is subject to Federal and State of California income tax at
      the highest marginal rates in effect for individuals."

      2.    The following new definition shall be inserted immediately after the
definition of "Indebtedness" on Page 6 of the Agreement:

            " `INITIAL PUBLIC OFFERING' shall mean a primary sale or sales of
      capital stock of Borrower pursuant to which not more than thirty percent
      (30%) of the issued capital stock of Borrower is offered for sale pursuant
      to a public offering thereof."

      3.    The following new definition shall be inserted immediately after the
definition of "Maturity Date" on Page 7 of the Agreement:

            " `NET PROCEEDS' shall mean proceeds from the Initial Public
      Offering net of (x) reasonable expenses associated with such issuance
      (including commissions, legal and accounting fees and other offering
      expenses), and (y) any tax expense incurred in connection with the
      termination of Borrower's election to be treated as an S corporation, to
      the extent such termination occurs in connection with the

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      Initial Public Offering, provided that the aggregate amount deducted on
      account of expenses described in clauses (x) and (y) shall not exceed
      fifteen percent (15%) of the gross proceeds of the Initial Public
      Offering."

      4.    Section 7.1 of the Agreement is hereby amended and restated in its
entirety as follows:

            "7.1 Declare or pay any cash dividends on, or make any other cash
      distribution (whether by reduction of capital or otherwise) with respect
      to any shares of its capital stock, other than:

            (a)   so long as Borrower is taxed as a Subchapter S corporation and
      is not in default under this Agreement or the Notes, Borrower may
      distribute to its shareholders such amounts (herein called "Permitted
      Distribution Amounts") as may be required to allow such shareholders to
      pay actual or estimated Corporate Tax Liability;

            (b)   so long as Borrower is not in default under this Agreement or
      the Notes, Borrower may distribute to its shareholders Permitted
      Distribution Amounts in an aggregate amount not to exceed Seven Hundred
      Fifty Thousand Dollars ($750,000) per annum for application against actual
      or estimated personal income tax expenses owing and arising out of
      investment income or other earnings, except for Corporate Tax Liability;

            (c)   a dividend payable in cash or by means of one or more
      promissory notes to Borrower's shareholders in an aggregate amount not to
      exceed the lesser of (i) the retained earnings of Borrower or (ii) Twenty
      Million Dollars ($20,000,000) which may be declared by Borrower prior to
      the Initial Public Offering and shall be considered shareholder equity for
      purposes of determining financial covenant calculations under this
      Agreement, provided that the payment thereof is conditioned upon: (i) the
      Initial Public Offering being completed on or before October 31, 2000 (the
      "IPO Date") and (ii) the Net Proceeds thereof being equal to or greater
      than Thirty Five Million Dollars ($35,000,000);

            (d)   the repayment of additional paid in capital either in cash or
      by means of one or more promissory notes to Borrower's shareholders in an
      aggregate amount of Three Million Dollars ($3,000,000), provided that the
      payment thereof is conditioned upon: (i) the Initial Public Offering being
      completed on or before the IPO Date, and (ii) the Net Proceeds thereof
      being equal to or greater than Thirty Five Million Dollars ($35,000,000);
      and

            (e)   the distribution permitted in Section 6.7 of the Agreement, as
      amended by the First Amendment to Credit Agreement;

            provided however, that dividends and distributions otherwise
      permitted hereunder may only be declared and/or paid if, upon giving
      effect to such declaration and/or payment, no Default or Event of Default
      shall exist."

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      5.    Section 7.2(b) of the Agreement is hereby amended and restated in
its entirety as follows:

            "7.2(b) Incur, create, assume or permit to exist any indebtedness or
            liability on account of deposits or advances or any indebtedness or
            liability for borrowed money, or any other indebtedness or liability
            evidenced by notes, bonds, debentures or similar obligations, or any
            other indebtedness whatsoever, except for (i) the Debt on the
            obligations from time to time secured by the Permitted Liens, (ii)
            the dividend payable notes described in Section 7.1(c) and (iii) the
            paid in capital notes described in Section 7.1(d)."

      6.    The following new section is added immediately after Section 7.10 of
the Agreement:

            "7.11 STOCK ISSUANCE. Issue any additional shares of its capital
            stock other than shares issued and authorized for sale pursuant to
            the Initial Public Offering."

      7.    Company hereby ratifies and reaffirms the representations,
warranties and covenants set forth in the Agreement.

      8.    Company certifies that no Event of Default or Default (as defined in
the Agreement) has occurred and is continuing.

      9.    Company represents and warrants that its Articles of Incorporation
and Bylaws delivered to Bank as of March 10, 2000 in connection with the
Agreement, are in full force and effect and have not been modified, repealed or
amended since the date thereof.

      10.   If any provision of this Amendment shall be held invalid or
unenforceable, such invalidity or unenforceability shall affect only such
provision and shall not in any manner affect or render invalid or unenforceable
any other provision of this Amendment, and this Amendment shall be enforced as
if any such invalid or unenforceable provision were not contained herein.

      11.   Except as specifically amended hereby, the Agreement shall remain
unchanged and shall be in full force and effect, enforceable in accordance with
its terms.

      12.   Borrower agrees to pay all of Bank's costs and expenses (including
attorneys fees and expenses) incurred in connection with the Agreement and/or
this Amendment within fifteen (15) days of being presented with an invoice
therefor.

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      IN WITNESS WHEREOF, this Amendment has been executed as of the day first
stated above.

                                       SIMPLE TECHNOLOGY, INC.


                                       By: /s/ Manouch Moshayedi
                                           ------------------------------------
                                               Manouch Moshayedi
                                       Its:    CEO

                                       COMERICA BANK


                                       By: /s/ Mark C. Smith
                                           ------------------------------------
                                               Mark C. Smith
                                       Its:    Vice President