<PAGE>   1
                                                                  Exhibit 10.66

IMPERIAL BANK                            GENERAL SECURITY AGREEMENT
Member FDIC
                                   (TANGIBLE AND INTANGIBLE PERSONAL PROPERTY

This Agreement is executed on JUNE 9, 1998                            , by

ALPHA MICROSYSTEMS                              (HEREINAFTER CALLED "OBLIGOR"). 
In consideration of financial accommodations given, to be given or continued,
the Obligor grants to IMPERIAL BANK (hereinafter called "Bank") a security
interest in (a) all property (i) delivered to Bank by Obligor, (ii) which shall
be in Bank's possession or control in any matter or for any purpose, (iii)
described below, (iv) now owned or hereafter acquired by Obligor of the type or
class described below and/or in any supplementary schedule hereto, or in any
financing statement filed by Bank and executed by or on behalf of Obligor; (b)
all deposits accounts of Obligor at Bank and (c) the proceeds, increase and
products of such property, all accessions thereto, and all property which
Obligor may receive on account of such collateral which Obligor will immediately
deliver to Bank (collectively referred to as "Collateral") to secure payment and
performance of all of Obligor's present or future debts or obligations to Bank,
whether absolute or contingent (hereafter referred to as "Debt"). Unless
otherwise defined, words used herein have the meanings given them in the
California Uniform Commercial Code.

Collateral:

A. VEHICLE, VESSEL, AIRCRAFT:
-------------------------------------------------------------------------------
                                Identification  License or
Year  Make/Manufacturer  Model  and Serial No.  Registration No.  New or Used
-------------------------------------------------------------------------------


Engine or other equipment:
(For aircraft - original ink signature on copy to FAA)

B. DEPOSIT ACCOUNTS:


Type                     Account Number                    Amount $
      ------------------                ----------------           -----------

In name of                                  Depository
            -------------------------------             ----------------------
AND ALL EXTENSIONS OR RENEWALS THEREOF.

C. ACCOUNTS, INTANGIBLES AND OTHER: (Describe)


        All personal property, whether presently existing or hereafter created
        or acquired, including but not limited to: All accounts, chattel paper,
        documents, instruments, money, deposit accounts and general intangibles
        including returns, repossessions, books and records relating thereto,
        and equipment containing said books and records. All Investment property
        including securities and securities entitlements. All goods including
        equipment and inventory. All proceeds including, without limitation,
        insurance proceeds. All guarantees and other security therefor.





The collateral not in Bank's possession will be located at 2722 S. FAIRVIEW 
STREET. SANTA ANAL CA 92704

   If checked, the Obligor is executing this Agreement as an Accommodation
Debtor only and the Obligor's liability is limited to the security interest
granted in the Collateral described herein. The party being accommodated is




 .                                                               ("Borrower").


                                                                    Page 1 of 4

<PAGE>   2


All the terms and provisions on page 3 hereof are incorporated herein as though
set forth in full, and constitute a part of this Agreement.

                              Signature
Name                 (indicate title, if applicable)            Address
                                                        2722 S. FAIRVIEW STREET
ALPHA MICROSYSTEMS                                      SANTA ANA CA 92704
------------------   -------------------------------    -----------------------

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

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







                                                                    Page 2 of 4

<PAGE>   3


                         SECURITY AGREEMENT (CONTINUED)

Obligor represents, warrants and agrees:

1. Obligor will immediately pay (a) any Debt when due, (b) Bank's costs of
collecting the Debt, of protecting, insuring or realizing on Collateral, and any
expenditure of Bank pursuant hereto, including attorneys' fees and expenses,
with interest at the rate of 24% per year, or the rate applicable to the Debt
whichever is less, from due date of expenditure, and (c) any deficiency after
realization of Collateral.

2. Obligor will use the proceeds of any loan that becomes Debt hereunder for the
purpose indicated on the application therefore, and will promptly contract to
purchase and pay the purchase price of any property which becomes Collateral
hereunder from the proceeds of any loan made for that purpose.

3. As to all Collateral in Obligor's possession (unless specifically
otherwise agreed to by Bank in writing), Obligor will:

   (a) Have, or has, possession of the Collateral at the location disclosed to
   Bank and will not remove the Collateral from the location.

   (b) Keep the Collateral separate and identifiable

   (c) Maintain the Collateral in good and saleable condition, repair it if
   necessary, clean, feed, shelter. water, medicate, fertilize, cultivate,
   irrigate, prune and otherwise deal with the Collateral in all such ways as
   are considered good practice by owners of like property, use it lawfully and
   only as permitted by insurance policies, and permit Bank to inspect the
   Collateral at any reasonable time.

   (d) Not sell, contract to sell, lease, encumber or transfer the Collateral
   (other than inventory Collateral) until the Debt has been paid, even though
   Bank has a security interest in proceeds of such Collateral.

4. As to Collateral which is inventory and accounts, Obligor:

   (a) May, until notice from Bank, sell, lease or otherwise dispose of
   inventory Collateral in the ordinary course of business only, and collect the
   cash proceeds thereof.

   (b) Will, upon notice from Bank, deposit all cash proceeds as received in a
   demand deposit account with Bank, containing only such proceeds and deliver
   statements identifying units of inventory disposed of, accounts which gave
   rise to proceeds, and all acquisitions and returns of inventory as required
   by Bank.

   (c) Will receive in trust, schedule on forms satisfactory to the Bank and
   deliver to Bank all non-cash proceeds other than inventory received in trade.

   (d) If not in default, may obtain release of Bank's interest in individual
   units of inventory upon request, therefore, payment to Bank of the release
   price of such units shown on any Collateral schedule supplementary hereto,
   and compliance herewith as to proceeds thereof.

5. As to Collateral which are accounts, chattel paper, general intangibles and
proceeds described in 4(c) above, Obligor warrants, represents and agrees:

   (a) All such Collateral is genuine, enforceable in accordance with its terms
   free from default, prepayment, defense and conditions precedent (except as
   disclosed to and accepted by Bank in writing), and is supported by
   consecutively numbered invoices to, or rights against, the debtors thereon.
   Obligor will supply Bank with duplicate invoices or other evidence of
   Obligor's rights on Bank's request;

   (b) All persons appearing to be obligated on such Collateral have authority
   and capacity to contract;

   (c) All chattel paper is in compliance with law as to form, content and
   manner of preparation and execution and has been properly registered,
   recorded, and/or filed to protect Obligor's interest thereunder;

   (d) If an account debtor shall also be indebted to Obligor on another
   obligation, any payment made by him not specifically designated to be applied
   on any particular obligation shall be considered to be a payment on the
   account in which Bank has a security interest. Should any remittance include
   a payment not on an account, it shall be delivered to Bank and, if no event
   of default has occurred, Bank shall pay Obligor the amount of such payment;

   (e) Obligor agrees not to compromise, settle or adjust any account or renew
   or extend the time of payment thereof without Bank's prior written consent.

6. Obligor owns all Collateral absolutely, and no other person has or claims any
interest in any Collateral, except as disclosed to and accepted by Bank in
writing. Obligor will defend any proceeding which may affect title to or Bank's
security interest in any Collateral, and will indemnify and hold Bank free and
harmless from all costs and expenses of Bank's defense.

7. Obligor will pay when due all existing or future charges, liens or
encumbrances on and all taxes and assessments now or hereafter imposed on or
affecting the Collateral and, if the Collateral is in Obligor's possession, the
realty on which the Collateral is located.

8. Obligor will insure the Collateral with Bank as loss payee in form and
amounts with companies, and against risks and liability satisfactory to Bank,
and hereby assigns such policies to Bank, agrees to deliver them to Bank at
Bank's request, and authorizes Bank to make any claim thereunder, to cancel the
insurance on Obligor's default, and to receive payment of and endorse any
instrument in payment of any loss or return premium. If Obligor should fail to
deliver the required policy or policies to the Bank, Bank may, at Obligor's cost
and expense, without any duty to do so, get and pay for insurance naming as the
insured, at Bank's option, either both Obligor and Bank, or only Bank, and the
cost thereof shall be secured by this Security Agreement, and shall be repayable
as provided in Paragraph 1 above.

9. Obligor will give Bank any information it requires. All information at any
time supplied to Bank by Obligor (including, but not limited to, the value and
condition of Collateral, financial statements, financing statements, and
statements made in documentary Collateral) is correct and complete, and Obligor
will notify Bank of any adverse change in such information. Obligor will
promptly notify Bank of any change of Obligor's residence, chief executive
office or mailing address.

10. Bank is irrevocably appointed Obligor's attorney-in-fact to do any act which
Obligor is obligated hereby to do, to exercise such rights as Obligor may
exercise, to use such equipment as Obligor might use, to enter Obligor's
premises to give notice of Bank's security interest, and to collect Collateral
and proceeds and to execute and file in Obligor's name any financing statements
and amendments thereto required to perfect Bank's security interest hereunder,
all to protect and preserve the Collateral and Bank's rights hereunder. Bank
may:

   (a) Endorse, collect and receive delivery or payment of instruments and
   documents constituting Collateral;

   (b) Make extension agreements with respect to or affecting Collateral,
   exchange it for other Collateral, release persons liable thereon or take
   security for the payment thereof, and compromise disputes in connection
   therewith;

   (c) Use or operate Collateral for the purpose of preserving Collateral or its
   value and for preserving or liquidating Collateral.



                                                                     Page 3 of 4


<PAGE>   4

11. If more than one Obligor signs this Agreement, their liability is joint
and several. Any Obligor who is married agrees that recourse may be had against
separate property for the Debt. Discharge of any Obligor except for full
payment, or any extension, forbearance, change of rate of interest, or
acceptance, release or substitution of Collateral or any impairment or
suspension of Bank's rights against an Obligor, or any transfer of an Obligor's
interest to another shall not affect the liability of any other Obligor. Until
the Debt shall have been paid or performed in full, Bank's rights shall continue
even if the Debt is outlawed. All Obligors waive: (a) any right to require Bank
to proceed against any Obligor before any other, or to pursue any other remedy;
(b) presentment, protest and notice of protest, demand and notice of nonpayment,
demand or performance, notice of sale, and advertisement of sale; (c) any right
to the benefit of or to direct the application of any Collateral until the Debt
shall have been paid; (d) and any right of subrogation to Bank until Debt shall
have been paid or performed in full.

12. Upon default, at Bank's option, without demand or notice, all or any part
of the Debt shall immediately become due. Bank shall have all rights given by
law, and may sell, in one or more sales, Collateral in any county where Bank has
an office. Bank may purchase at such sale. Sales for cash or on credit to a
wholesaler, retailer or user of the Collateral, or at public or private auction,
are all to be considered commercially reasonable. Bank may require Obligor to
assemble the Collateral and make it available to Bank at the entrance to the
location of the Collateral, or a place designated by Bank.

   Defaults shall include:

   (a) Obligor's failure to pay or perform this or any agreement with Bank or
   breach of any warranty herein, or Borrower's failure to pay or perform any
   agreement with Bank.

   (b) Any change in Obligor's or Borrower's financial condition which in Bank's
   judgment impairs the prospect of Borrower's payment or performance.

   (c) Any actual or reasonably anticipated deterioration of the Collateral or
   in the market price thereof which causes it, in Bank's judgment, to become
   unsatisfactory as security.

   (d) Any levy or seizure against Borrower or any of the Collateral.

   (e) Death, termination of business, assignment for creditors, insolvency,
   appointment of receiver, or the filing of any petition under bankruptcy or
   debtor's relief laws of, by or against Obligor or Borrower or any guarantor
   of the Debt.

   (f) Any warranty or representation which is false or is believed in good
   faith by Bank to be false.

13. Bank's acceptance of partial or delinquent payments or the failure of Bank
to exercise any right or remedy shall not waive any obligation of Obligor or
Borrower or right of Bank to modify this Agreement, or waive any other similar
default.

14. On transfer of all or any pan of the Debt, Bank may transfer all or any part
of the Collateral. Bank may deliver all or any part of the Collateral to any
Obligor at any time. Any such transfer or delivery shall discharge Bank from all
liability and responsibility with respect to such Collateral transferred or
delivered. This Agreement benefits Bank's successors and assigns and binds
Obligor's heirs, legatees, personal representatives, successors and assigns.
Obligor agrees not to assert against any assignee of Bank any claim or defense
that may exist against Bank. Time is of the essence. This Agreement and
supplementary schedules hereto contain the entire security agreement between
Bank and Obligor. Obligor will execute any additional agreements, assignments or
documents reasonably required by Bank to carry this Agreement into effect.

15. This Agreement shall be governed by and construed in accordance with the
laws of the State of California, to the jurisdiction of whose courts the Obligor
hereby agrees to submit. Obligor agrees that service of process may be
accomplished by any means authorized by California law. All words used herein in
the singular shall be considered to have been used in the plural where thc
context and construction so require.

16. To thc extent that Obligor acquires any trademarks, service marks, trade
names and service names and/or the goodwill associated therewith, copyrights,
patents and/or patent applications (collectively "Intellectual Property"),
Obligor shall give prompt notice thereof to Bank and shall take any and all
actions requested from time to time by Bank to perfect Obligor's interest in
such Intellectual Property and to perfect Bank's first priority interest
therein. Without limiting the generality of the foregoing, the Obligor agrees as
follows: Upon Obligor creating, writing, producing or acquiring any software,
computer source codes or other computer programs (collectively, the "Software"),
Obligor shall promptly register such Software with the U.S. Copyright Office and
to the extent Obligor's rights therein are acquired from any third party,
Obligor shall promptly upon such acquisition file with the U.S. Copyright Office
any and all documents necessary to perfect Obligor's rights therein. Upon
Obligor creating, writing, producing or otherwise acquiring any Software,
Obligor shall give prompt notice thereof to Bank. Obligor shall execute and
deliver to Bank any and all copyright mortgages, UCC financing statements and
other documents and instruments which Bank may request in connection with the
Bank perfecting its first priority security interest in such Software.




                                                                    Page 4 of 4