<PAGE>   1
                                                                EXHIBIT 10.150



[LOGO]  SILICON VALLEY BANK

                          AMENDMENT TO LOAN AGREEMENT



BORROWER:     ALPHA MICROSYSTEMS
ADDRESS:      2722 SOUTH FAIRVIEW STREET
              SANTA ANA, CALIFORNIA  92704

DATE:         NOVEMBER 30, 1995



              THIS AMENDMENT TO LOAN AGREEMENT is entered into between SILICON
VALLEY BANK ("Silicon") and the borrower named above (the "Borrower").

              The Parties agree to amend the Loan and Security Agreement
between them (the "Loan Agreement") dated July 28, 1995, effective as of the
date hereof.  (Capitalized terms used but not defined in this Amendment, shall
have the meanings set forth in the Loan Agreement.)

              1.   MODIFICATION TO FINANCIAL COVENANTS.  The section of the
Schedule to the Loan Agreement entitled "Financial Covenants (Section 4.1) is
hereby deleted in its entirety and replaced with the following:

      "FINANCIAL COVENANTS
         (Section 4.1):        Borrower shall comply with all of the following
                               covenants.  Compliance shall be determined as of
                               the end of each month, except as otherwise
                               specifically provided below:

      QUICK ASSET RATIO:       Borrower shall maintain a ratio of "Quick
                               Assets" to current liabilities of not less than 
                               1.30 to 1.

      TANGIBLE NET WORTH:      Borrower shall maintain a tangible net worth of
                               not less than $5,900,000.

      DEBT TO TANGIBLE
      NET WORTH RATIO:         Borrower shall maintain a ratio of total
                               liabilities to tangible net worth of not more 
                               than 1.00 to 1.

      PROFITABILITY            Borrower shall not incur a loss (after taxes)
                               for any fiscal year, provided that Borrower may
                               incur losses (after taxes) in two consecutive
                               fiscal quarters during any fiscal year if the
                               aggregate amount of such losses for such two
                               fiscal quarters does not exceed $700,000.

      DEFINITIONS:             "Current assets," and "current liabilities"
                               shall have the meanings ascribed to them in
                               accordance with generally accepted accounting
                               principles.
                               

<PAGE>   2
                               "Tangible net worth" means the excess of total
                               assets over total liabilities, determined in
                               accordance with generally accepted accounting
                               principles, excluding however all assets which
                               would be classified as intangible assets under
                               generally accepted accounting principles,
                               including without limitation goodwill, licenses,
                               patents, trademarks, trade names, copyrights,
                               capitalized software and organizational costs,
                               licences and franchises.

                               "Quick Assets" means cash on hand or on deposit
                               in banks, readily marketable securities issued
                               by the United States, readily marketable
                               commercial paper rated "A-1" by Standard &
                               Poor's Corporation (or a similar rating by a
                               similar rating organization), certificates of
                               deposit and banker's acceptances, and accounts
                               receivable (net of allowance for doubtful
                               accounts).

      DEFERRED REVENUES:       For purposes of the above quick asset ratio,
                               deferred revenues shall not be counted as
                               current liabilities.  For purposes of the above
                               debt to tangible net worth ratio, deferred
                               revenues shall not be counted in determining
                               total liabilities but shall be counted in
                               determining tangible net worth for purposes of
                               such ratio.  For all other purposes deferred
                               revenues shall be counted as liabilities in
                               accordance with generally accepted accounting
                               principles.

      SUBORDINATED DEBT:       "Liabilities" for purposes of the foregoing
                               covenants do not include indebtedness which is
                               subordinated to the indebtedness to Silicon
                               under a subordination agreement in form
                               specified by Silicon or by language in the
                               instrument evidencing the indebtedness which is
                               acceptable to Silicon."


              2.   REPRESENTATIONS TRUE.  Borrower represents and warrants
to Silicon that all representations and warranties set forth in the Loan
Agreement, as amended hereby, are true and correct.

              3.   GENERAL PROVISIONS.  This Amendment, the Loan Agreement,
any prior written amendments to the Loan Agreement signed by Silicon and the
Borrower, and the other written documents and agreements between Silicon and
the Borrower set forth in full all of the representations and agreements of the
parties with respect to the subject matter hereof and supersede all prior
discussions, representations, agreements and understandings between the parties
with respect to the subject hereof.  Except as herein expressly amended, all of
the terms and provisions of the Loan Agreement, and all other documents and
agreements between Silicon and the Borrower shall continue in full force and
effect and the same are hereby ratified and confirmed.

  BORROWER:                                 SILICON:                          
                                                                              
  ALPHA MICROSYSTEMS                        SILICON VALLEY BANK               
                                                                              
  BY     MICHAEL J. LOWELL                  BY      MICHAEL P. QUAIN    
    --------------------------------          --------------------------------
         PRESIDENT OR VICE PRESIDENT        TITLE   Assistant Vice President    
                                                 -----------------------------
  BY    JOHN F. GLADE    
    --------------------------------
        SECRETARY OR ASS'T SECRETARY



                                      -2-
<PAGE>   3



                              GUARANTOR'S CONSENT

     The undersigned guarantor acknowledges that its consent to the foregoing
Amendment is not required, but the undersigned nevertheless does hereby consent
to the foregoing Amendment and to the documents and agreements referred to
therein and to all future modifications and amendments thereto, and to any and
all other present and future documents and agreements between or among the
foregoing parties.  Nothing herein shall in any way limit any of the terms or
provisions of the Continuing Guaranty executed by the undersigned in favor of
Silicon, which is hereby ratified and affirmed and shall continue in full force
and effect.


                                         ALPHAHEALTHCARE, INC.

                                         By:     MICHAEL J. LOWELL
                                            ---------------------------------
                                         Title:  V.P. & CFO
                                               ------------------------------


                                      -3-