<PAGE>
                                                                   Exhibit 10.73


                                FIRST AMENDMENT
                         TO LOAN AND SECURITY AGREEMENT

  This First Amendment to Loan and Security Agreement is entered into as of June
30, 2003 (the "Amendment"), by and between COMERICA BANK, successor by merger
(effective July 1, 2003) to  COMERICA BANK-CALIFORNIA ("Bank") and MTI
TECHNOLOGY CORPORATION ("BORROWER").

                                    RECITALS

  Borrower and Bank are parties to that certain Loan and Security Agreement
dated as of November 13, 2002, as amended from time to time (the "Loan
Agreement"). The parties desire to amend the Loan Agreement in accordance with
the terms of this Amendment.

  NOW, THEREFORE, the parties agree as follows:

1.  The definition of Revolving Maturity Date in Section 1.1 of the Loan
Agreement is amended in its entirety to read as follows:

      "Revolving Maturity Date" means May 31, 2004.

2.  Unless otherwise defined, all capitalized terms in this Amendment shall be
as defined in the Loan Agreement. Except as amended, the Loan Agreement remains
in full force and effect.

3.  Borrower represents and warrants that the representations and warranties
contained in the Loan Agreement are true and correct as of the date of this
Amendment, and that no Event of Default has occurred and is continuing.

4.  This Amendment may be executed in two or more counterparts, each of which
shall be deemed an original, but all of which together shall constitute one
instrument.

5.  As a condition to the effectiveness of this Amendment, unless waived by
Bank, Bank shall have received, in form and substance satisfactory to Bank, the
following:

      (a) this Amendment duly executed by:

      (b) the Standby Letter of Credit, issued by Bank of America for the
benefit of Bank, in the minimum amount of the Revolving Line, shall be amended
or reissued to bear an expiry date of no earlier than June 30, 2004;

      (c) an amount equal to all expenses incurred to date in connection with
the Loan Documents; and

      (d) such other documents, and completion of such other matters, as Bank
may reasonably deem necessary or appropriate.

      IN WITNESS WHEREOF, the undersigned have executed this Amendment as of
the first date above written.


                                          COMERICA BANK, successor by merger to
                                          COMERICA BANK-CALIFORNIA

                                          By: /s/ Derek Hout
                                              _______________________________

                                          Name: Derek Hout
                                                _____________________________

                                          Title: Assistant Vice President
                                                _____________________________



                                          MTI TECHNOLOGY CORPORATION

                                          By: /s/ Mark A. Franzen

                                          Name:   Mark A. Franzen
                                                _______________________________

                                          Title:  CFO
                                                _______________________________
<PAGE>
                        CORPORATE RESOLUTIONS TO BORROW

------------------------------------------------------------------------------

BORROWER:  MTI TECHNOLOGY CORPORATION

------------------------------------------------------------------------------

     I, the undersigned Secretary or Assistant Secretary of MTI TECHNOLOGY
CORPORATION (the "Corporation"), HEREBY CERTIFY that the Corporation is
organized and existing under and by virtue of the laws of Delaware.

     I FURTHER CERTIFY that attached hereto as Attachments 1 and 2 are true and
complete copies of the Certificate of Incorporation, as amended, and the Bylaws
of the Corporation, each of which is in full force and effect on the date
hereof.

     I FURTHER CERTIFY that at a meeting of the Directors of the Corporation
duly called and held, at which a quorum was present and voting, (or by other
duly authorized corporate action in lieu of a meeting), the following
resolutions were adopted.

     BE IT RESOLVED, that ANY ONE (1) of the following named officers,
employees, or agents of this Corporation, whose actual signatures are shown
below:
              Mark Franzen
<Table>
<Caption>
   NAMES                   POSITIONS                  ACTUAL SIGNATURES
   -----                   ---------                  -----------------
<S>                   <C>                            <C>
Tom Raimodi                     CEO                  /s/ TOM RAIMODI
--------------        -----------------------        -------------------------
Mark Franzen                    CFO                  /s/ Mark Franzen
--------------        -----------------------        -------------------------

Todd Schaeffer            VP - Controller            /s/ TODD SCHAEFFER
--------------        -----------------------        -------------------------

Mark Almorda          Financial Planning Mgr.       /s/ MARK ALMORDA
--------------        -----------------------        -------------------------
</Table>


acting for and on behalf of this Corporation and as its act and deed be, and
they hereby are, authorized and empowered:

     BORROW MONEY. To borrow from time to time from Comerica Bank, successor by
merger to Comerica Bank-California ("Bank"), on such terms as may be agreed
upon between the officers, employees, or agents and Bank, such sum or sums of
money as in their judgment should be borrowed, without limitation, including
such sums as are specified in that certain Loan and Security Agreement dated as
of November 13, 2002, as amended from time to time, including but not limited
to that certain First Amendment to Loan and Security Agreement dated as of June
30, 2003 (the "Amendment").

     EXECUTE AMENDMENTS. To execute and deliver to Bank the Amendment, and also
to execute and deliver to Bank one or more renewals, extensions, modifications,
consolidations, or substitutions therefor.

     GRANT SECURITY. To grant a security interest to Bank in the Collateral
described in the Amendment, which security interest shall secure all of the
Corporation's Obligations, as described in the Amendment.

     NEGOTIATE ITEMS. To draw, endorse, and discount with Bank all drafts,
trade acceptances, promissory notes, or other evidences of indebtedness payable
to or belonging to the Corporation or in which the Corporation may have an
interest, and either to receive cash for the same or to cause such proceeds to
be credited to the account of the Corporation with Bank, or to cause such other
disposition of the proceeds derived therefrom as they may deem advisable.


<PAGE>
     FURTHER ACTS. In the case of lines of credit, to designate additional or
alternate individuals as being authorized to request advances thereunder, and in
all cases, to do and perform such other acts and things, to pay any and all fees
and costs, and to execute and deliver such other documents and agreements as
they may in their discretion deem reasonably necessary or proper in order to
carry into effect the provisions of these resolutions.

     BE IT FURTHER RESOLVED, that any and all acts authorized pursuant to these
resolutions and performed prior to the passage of these resolutions are hereby
ratified and approved, that these resolutions shall remain in full force and
effect and Bank may rely on these resolutions until written notice of their
revocation shall have been delivered to and received by Bank. Any such notice
shall not affect any of the Corporation's agreements or commitments in effect at
the time notice is given.

     I FURTHER CERTIFY that the officers, employees, and agents named above are
duly elected, appointed, or employed by or for the Corporation, as the case may
be, and occupy the positions set forth opposite their respective names; that the
foregoing resolutions now stand of record on the books of the Corporation; and
that the Resolutions are in full force and effect and have not been modified or
revoked in any manner whatsoever.

     IN WITNESS WHEREOF, I have hereunto set my hand on June 30, 2003 and attest
that the signatures set opposite the names listed above are their genuine
signatures.

                                                  CERTIFIED TO AND ATTESTED BY:


                                                  X /s/ MARK A. FRANZEN
                                                   ____________________________

<PAGE>
[BANK OF AMERICA LETTERHEAD]


DATE: JUNE 30, 2003

AMENDMENT TO IRREVOCABLE STANDBY LETTER OF CREDIT NUMBER: 3051683

AMENDMENT NUMBER 2



             BENEFICIARY                             APPLICANT
COMERICA BANK CALIFORNIA                     MTI TECHNOLOGY CORPORATION
INTERNATIONAL DIVISION                       4905 E. LA PALMA AVE.
9920 SOUTH LA CIENEGA BLVD 11TH FLR        ANAHEIM, CA 92807
INGLEWOOD, CA 90301-4423


THIS AMENDMENT IS TO BE CONSIDERED AN INTEGRAL PART OF THE ABOVE CREDIT AND
MUST BE ATTACHED THERETO.

THE ABOVE MENTIONED CREDIT IS AMENDED AS FOLLOWS:

THE EXPIRATION DATE IS AMENDED TO: JUNE 30, 2004.

THE AUTOMATIC RENEWAL CLAUSE IS STILL IN EFFECT.

ALL OTHER TERMS AND CONDITIONS REMAIN UNCHANGED.

IF YOU REQUIRE ANY ASSISTANCE OR HAVE ANY QUESTIONS REGARDING THIS AMENDMENT,
PLEASE CALL 213-345-0042.


        /s/ Teena Evangelista                     /s/ Lawrence Banales
-------------------------------------    --------------------------------------
         AUTHORIZED SIGNATURE                      AUTHORIZED SIGNATURE
          TEENA EVANGELISTA                          LAWRENCE BANALES

                      THIS DOCUMENT CONSISTS OF 1 PAGE(S).