1
                              OPTION AGREEMENT II


                                    Between


                      Adaptec Manufacturing (S) Pte. Ltd.


                                      And


                  Taiwan Semiconductor Manufacturing Co., Ltd.


                                October 23, 1995
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                               TABLE OF CONTENTS


1.      DEFINITIONS                                                     1

2.      VOLUME CAPACITY                                                 2

3.      WAFER PRICE                                                     3

4.      OTHER PURCHASE TERMS AND CONDITIONS                             3

5.      OBLIGATION TO PAY OPTION FEE FOR OPTION CAPACITY                3

6.      FAILURE TO PURCHASE THE OPTION CAPACITY;                        4
        FIRST RIGHT OF REFUSAL                  

7.      TERM AND TERMINATION                                            4

8.      BOARD APPROVAL                                                  5

9.      LIMITATION OF LIABILITY                                         5

10.     NOTICE                                                          5

11.     ENTIRE AGREEMENT                                                6

12.     GOVERNING LAW                                                   6

13.     ARBITRATION                                                     7

14.     ASSIGNMENT                                                      7

15.     CONFIDENTIALITY                                                 7

16.     FORCE MAJEURE                                                   7

17.     NO AGENCY                                                       7

18.     GOVERNMENTAL APPROVAL                                           8

19.     COUNTERPARTS                                                    8
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                              OPTION AGREEMENT II


        THIS AGREEMENT is made and becomes effective as of October 23, 1995
(the "Effective Date") by Taiwan Semiconductor Manufacturing Co., Ltd. ("TSMC"),
a company organized under the laws of the Republic of China with its registered 
address at No. 121, Park Ave. 3, Science Based Industrial Park, Hsinchu, 
Taiwan and Adaptec Manufacturing (S) Pte. Ltd., a company organized under the 
laws of Singapore, with its registered address at 6 Battery Road, 532-00, 
Singapore 049909 ("Customer").

RECITALS

        WHEREAS, TSMC currently supplies Customer with wafers and Customer
wishes to increase the volume of wafers to be purchased from TSMC;

        WHEREAS, in order in increase its output, TSMC must accelerate its ramp 
up in Fab 3 and advance the start of Fab 4;

        WHEREAS, as condition to TSMC's acceleration of these facilities, TSMC 
has asked that Customers make a capacity commitment and advance payment for the 
right to buy additional capacity, and Customer is willing to do so:

AGREEMENT

        NOW, THEREFORE, in consideration of the mutual convents and 
conditions contained herein the parties agree as follows:

1.      DEFINITIONS

        (a)     "Base Capacity" used in this Agreement shall mean the annualized
                run rate that TSMC commits to provide to Customer as set forth 
                in Exhibit B.

        (b)     "Customer Committed Capacity" used in this Agreement shall mean 
                the total capacity that Customer agrees to purchase from TSMC 
                pursuant to this Agreement, either itself or by an Affiliate, 
                and as set forth in Exhibit B.

        (c)     "Foundry Agreement" used in this Agreement shall mean the 
                Foundry Agreement between TSMC and Adaptec, Inc., dated 
                October 29, 1993, together with any amendments thereto.

        (d)     "Option Capacity" used in this Agreement shall mean the firm 
                capacity commitment made by Customer pursuant to this 
                Agreement, for which


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         capacity Customer agrees to pay the Option Fee as defined in Section
         1(e) below.

    (e)  "Option Fee" used in this Agreement shall mean the deposit that
         Customer agrees to place with TSMC as the advance payment for the
         wafers comprising the Option Capacity.

    (f)  "TSMC Committed Capacity" used in this Agreement shall mean the total
         capacity that TSMC agrees to provide to Customer or its Affiliates,
         consisting of Base Capacity and Option Capacity as set forth in Exhibit
         B.

    (g)  "Wafer Equivalent" used in this Agreement shall mean the number of
         six-inch wafers, adjusted by the equivalency factor based on 1996 Base
         Capacity as set forth on Exhibit A, by which capacity commitments are
         measured hereunder. An example of such calculation is set forth on
         Exhibit B-1. Any and all capacity commitments referred to in this
         Agreement shall be for the calendar year and measured in Wafer
         Equivalents.

    (h)  "Affiliates" used in this Agreement shall mean a party which holds at
         least a seventy-five percent (75%) ownership interest in Customer or a
         party in which Customer's parent holds at least a seventh-five percent
         (75%) ownership interest.

2.  VOLUME COMMITMENT

    (a)  Customer agrees to purchase annually from TSMC, either itself or
         through its Affiliates, the Customer Committed Capacity set forth for
         such year on Exhibit B and, subject to the payment of the Option Fee by
         Customer under Section 5 below, TSMC agrees to provide to Customer the
         TSMC Committed Capacity, as set forth in Exhibit B. In any calendar
         year, the orders placed by Customer or its Affiliates shall first apply
         to fulfill the Base Capacity portion of the Customer Committed
         Capacity, and then the Option Capacity portion.

    (b)  Each month, Customer agrees to provide to TSMC a six-month rolling
         forecast of the number of wafers that Customer will purchase, with the
         volume for the first twelve weeks being frozen (i.e., Customer must
         purchase all of the quantity forecast for the delivery in the first
         twelve weeks of the forecast). The forecast must be based on wafers
         out.

    (c)  TSMC will use its best efforts to cause its fabs to be capable of
         producing wafers of more advanced specifications, as set forth in the
         TSMC Technology Road Map attached as Exhibit C. (The parties anticipate
         that the conversion factor for migration of 6" to 8" inch wafers will 
         1.78.) 


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3.  WAFER PRICE

    (a)  The prices for wafers purchased by Customer during the term of this
         Agreement shall not be more than TSMC's average wafer prices to the
         optionees (i.e., other customers that are parties to option agreements
         similar to this Agreement) for the same technology, the same fab and
         the same period of time, taking into account Customer's total volume
         across all TSMC fabs. At Customer's request, TSMC shall permit an
         independent third party mutually agreed upon by the parties to audit
         such books and records as may be required to verify TSMC's most favored
         customer pricing obligations in the preceding sentence. Such audits
         shall be at Customer's expense at any time during the term of this
         Agreement upon at least one (1) month prior written notice to TSMC. In
         the event that the wafer prices do not comply with the first sentence,
         TSMC will make proper price changes for all unfilled orders upon
         Customer's notice in writing.

    (b)  The parties shall negotiate in good faith each year the wafer prices
         for the Option Capacity of the following year, and if no agreement is
         reached by the parties before October of each year for the succeeding
         calendar year, the parties agree to submit the dispute to the binding
         arbitration pursuant to Section 13 below, and under such circumstances,
         neither party shall have the right to terminate this Agreement under
         Section 7 below.

4.  OTHER PURCHASE TERMS AND CONDITIONS

    The Foundry Agreement, together with any amendments thereto, will apply to
    all purchases of wafers by Customer from TSMC, except that the provisions of
    this Agreement will supersede the Foundry Agreement with respect to the
    subject matter hereof.

5.  OBLIGATION TO PAY OPTION FEE FOR OPTION CAPACITY

    (a)  Customer agrees to pay to TSMC the Option Fee in the amount of [* *]
         per Wafer Equivalent for the right to purchase the Option Capacity
         pursuant to this Agreement. The Option Fee is set forth in Exhibit D,
         and Customer agrees to pay the Option Fee for the entire term of this
         Agreement [* * * * * *] in cash by June 30, 1996. The Option Fee, once
         paid, shall be non-refundable, except as provided in Section 6(a) and
         Section 7(d), and will be credited against payments due for wafers
         purchased by Customer for the Option Capacity provided by TSMC under
         this Agreement.

    (b)  Customer agrees to deliver to TSMC, within seven (7) days following
         the Effective Date, a promissory note in an amount of the Option Fee
         and evidencing the payment required pursuant to Section 5(a), payable
         to TSMC or


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         order, which promissory note shall be in the form of Exhibit E. The
         promissory note shall be cancelled and returned by TSMC to customer
         within seven (7) days after receipt of the corresponding Option Fee by
         TSMC.

6.  FAILURE TO PURCHASE THE OPTION CAPACITY; FIRST RIGHT OF REFUSAL

    If, in any calendar year, for any reason, Customer is not able to use or
    purchase all or a portion of the Customer Committed Capacity for that year,
    Customer shall promptly notify TSMC of such in writing and first offer TSMC
    such capacity for sales to any third parties. TSMC may, at its option,
    accept such offer, in whole or in part, within thirty (30) days following
    Customer's notification and, if TSMC so accepts, the Option Fee attributable
    to that capacity will be refunded to Customer without interest. In the event
    that TSMC decides not to accept such offer, Customer may sell such unused
    capacity to third parties reasonably acceptable to TSMC (given the processes
    and capacity then available in its fabs), within two months after TSMC's
    written notice that it will not accept such offer. If Customer fails to sell
    such unused Customer Committed Capacity, TSMC shall not be required to
    refund any portion of the unapplied Option Fee applicable to that unused
    capacity. TSMC is entitled to sell or use any such capacity thereafter.
    Forfeiture of the applicable Option Fee shall be TSMC's sole remedy for
    Customer's failure to purchase the Customer Committed Capacity in any
    calendar year.

7.  TERM AND TERMINATION
  
    (a)  TERM

         The term of this Agreement shall commence from the Effective Date, and
         continue until December 31, 2000.

    (b)  TERMINATION BY TSMC FOR CUSTOMER'S FAILURE TO PAY THE OPTION FEE

         TSMC may terminate this Agreement if Customer fails to pay the Option
         Fee pursuant to Section 5 above, and does not cure or remedy such
         breach within thirty (30) days of receiving written notice of such
         breach.


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        (c)     TERMINATION FOR OTHER BREACH OR FOR BANKRUPTCY

                Either party may terminate this Agreement if, (i) the other 
                party breaches any material provisions of this Agreement (other
                than Customer's breach of Section 5 above), and does not cure or
                remedy such breach within one hundred and twenty (120) days of
                receiving written notice of such breach, or (ii) becomes the
                subject of a voluntary or involuntary petition in bankruptcy or
                any proceeding relating to insolvency, receivership or
                liquidation, if such petition or proceeding is not dismissed
                with prejudice within sixty (60) days after filing.

        (d)     EFFECT OF TERMINATION

                In the event of termination of this Agreement, each party shall 
                remain liable to the other party for any outstanding and matured
                rights and obligations at the time of termination, including
                payment of the Option Fee applicable to the used Option Capacity
                and for the wafers already ordered and shipped to Customer. Any
                wafers then in process pursuant to a Customer order may be
                completed and shipped to Customer and the applicable Option Fee
                amount applied against such wafers. In the event Customer
                terminates this Agreement pursuant to the terms of Section 7(c),
                any portion of the Option Fee then remaining, which has not been
                applied against purchases of wafers, will be refunded to
                Customer within thirty (30) days of termination of this
                Agreement.

 8.     BOARD APPROVAL

        Customer shall obtain the approval by its board of directors of this 
        Agreement, and submit to TSMC, at the time of executing this 
        Agreement, an authentic copy of its board resolution authorizing the 
        representative designated below to execute this Agreement.

 9.     LIMITATION OF LIABILITY

        In no event shall either party be liable for any indirect, special, 
        incidental or consequential damages (including loss of profits or loss 
        of use) resulting from, arising out of or in connection with such 
        party's performance or failure to perform under this Agreement, or 
        resulting from, arising out of or in connection with the production, 
        supply and/or purchase and sale of the wafers, whether due to a breach 
        of contract, breach of warranty, tort, or negligence of such party, or 
        otherwise.

10.     NOTICE

        All notices required or permitted to be sent by either party to the 
        other party under this Agreement shall be sent by registered mail 
        postage prepaid, or by personal

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        delivery, or by fax. Any notice given by fax shall be followed by a 
        confirmation copy within ten (10) days. Unless changed by written 
        notice given by either party to the other, the addresses and fax
        numbers of the respective parties shall be as follows:

        To TSMC:

        TAIWAN SEMICONDUCTOR MANUFACTURING COMPANY, LTD.
        No. 121, Park Avenue 3
        Science-Based Industrial Park
        Hsinchu, Taiwan
        Republic of China               FAX: 886-35-781545

        To Customer:

        ADAPTEC MANUFACTURING (S) PTE. LTD.
        Block 1001
        Julan Bukit Merah #07/01-20
        Singapore 0315

        With a copy to:

        ADAPTEC, INC.
        Attention: Vice President, Procurement
        691 South Milpitas Boulevard
        Milpitas, California 95035      FAX: (408) 262-2533

11.     ENTIRE AGREEMENT

        This Agreement, including Exhibits A-E, and together with the Foundry 
        Agreement, constitutes the entire Agreement between the parties with
        respect to the subject matter hereof, and supersedes and replaces all
        prior to contemporaneous understandings, agreements, dealings and
        negotiations, oral or written, regarding the subject matter hereof. No
        modification, alteration or amendment of this Agreement shall be
        effective unless in writing and signed by both parties. No waiver of any
        breach or failure by either party to enforce any provision of this
        Agreement shall be deemed a waiver of any other or subsequent breach, or
        a waiver of future enforcement of that or any other provision.

12.     GOVERNING LAW

        This Agreement will be governed by and interpreted in accordance with 
        the laws of the State of California.

13.     ARBITRATION

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        Each party will use its best efforts to resolve amicably any disputes 
        or claims under this Agreement between the parties. In the event that a
        resolution is not reached among the parties within thirty (30) days
        after written notice by any party of the dispute or claim, the dispute
        or claim shall be finally settled by binding arbitration in the San
        Francisco Bay Area, California under the Rules of Commercial Arbitration
        of the American Arbitration Association by three (3) arbitrators
        appointed in accordance with such rules. The arbitration proceeding
        shall be conducted in English. Judgment on the award rendered by the
        arbitrator may be entered in any court having jurisdiction thereof.

14.     ASSIGNMENT

        This Agreement shall be binding on and inure to the benefit of each 
        party and its permitted successors and assigns. Customer may assign its
        purchase rights and obligations under this Agreement (a) to third
        parties in accordance with Section 6 above, and (b) to its Affiliates.
        Except as provided in Section 6, neither party shall assign any of its
        rights hereunder, nor delegate its obligations hereunder, to any third
        party, without prior written consent of the other.

15.     CONFIDENTIALITY

        Neither party shall disclose the existence or contents of this 
        Agreement except as required by Customer's assignment of this Agreement
        to any third parties pursuant to Sections 6 and 14 above, in confidence
        to its advisors, as required by applicable law, or otherwise with the
        prior written consent of the other party.

16.     FORCE MAJEURE

        Neither party shall be responsible for delays or failure in performance
        resulting from acts beyond the reasonable control of such party. Such
        acts shall include but not be limited to acts of God, war, riot, labor
        stoppages, governmental actions, fires, floods, and earthquakes. If such
        delays or failures on the party of either party continue for a period of
        more than one hundred twenty (120) days, the other party may terminate
        this Agreement upon written notice, subject to Section 7(d).

17.     NO AGENCY

        No agency, partnership, joint venture, teaming agreement or other joint
        relationship is created hereby and neither party, nor any of its agents
        or representatives, has any authority of any kind to bind the other 
        party in any respect whatsoever.

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18.     GOVERNMENTAL APPROVAL

        TSMC represents and warrants to Customer that no governmental approval
        or registration by or with the ROC is required for this Agreement or for
        the transactions contemplated hereby. In the event any such approval or
        registration is required, TSMC agrees to indemnify and hold Customer
        harmless from any and all loss or damage to Customer which may result
        from the failure to procure such approval or effect such registration.

19.     COUNTERPARTS

        This Agreement may be executed in two counterparts, together which will
        constitute a fully executed Agreement.

        IN WITNESS WHEREOF, the parties, have executed this Agreement as of the 
Effective Date by their duly authorized representatives.


TAIWAN SEMICONDUCTOR                          ADAPTEC MANUFACTURING
MANUFACTURING CO., LTD.                         (S) PTE. LTD.



By: /s/ Donald Brooks                         By: /s/ Sam Kazarian
    ------------------                            ------------------
    Donald Brooks                                 Sam Kazarian
    President                                     Director and Attorney-In-Fact

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                                   Exhibit A
                             CAPACITY FACTOR TABLE

                               Masking       W-Plug      Complexity    Capacity
Generic Technology            Layers(A)     Layers(B)     Index(C)     Factor(D)
                             (w/o ESD or
                              Polyimide)
                
1.5um SPDM (BiCMOS)              16                          16          1.23
1.2um SPDM (Logic)               13                          13          1.00
1.0um SPDM (Logic)               13                          13          1.00
1.0um DPDM (BiCMOS)              18                          18          1.38
0.8um SPDM (Logic)               13                          13          1.00
0.8um DPDM (MixMode)             14                          14          1.08
0.8um SPTM (Logic Salicide)      17                          17          1.31
0.8um DPDM (BiCMOS)              22                          22          1.69
0.6um SPDM (Logic)               14            1            14.5         1.12
0.6um SPTM (Logic)               16            1            16.5         1.27
0.6um DPDM (MixMode)             15            1            15.5         1.19
0.6um DPDM (SRAM)                20                          20          1.54
0.6um TPSM (DRAM)                15            1            15.5         1.19
0.6um QPDM (DRAM)                18            1            18.5         1.42
0.5um SPDM (Logic)               14            2             15          1.15
0.5um SPTM (Logic SACVD)         16            3            17.5         1.35
0.5um SPTM (Logic-CMP)           21            3            22.5         1.73
0.5um DPDM (SRAM)                20            1            20.5         1.58
0.5um QPDM (DRAM)                21            1            21.5         1.65
0.35um SPTM (Logic-CMP)          21            3            22.5         1.73

Remarks:   (1) Masking Layer of w/i ESD (or Polyimide) = Masking Layer of w/o
               ESD (or Polyimide) + 1
           (2) Masking Layer of Mixed-Mode(DP) = Masking Layer of Logic(SP) + 1
           (3) Complexity Index (C) = (A) + (B) / 2
           (4) Capacity Factor (D) = (C) / 13, normalized to 0.8um SPDM as 1

Date of issue: 6/9/95
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                                   EXHIBIT B
                        CUSTOMER/TSMC COMMITTED CAPACITY

                                                     Unit: K 6" Wafer Equivalent




                        1996    1997    1998    1999    2000
                        ----    ----    ----    ----    ----
                                         
Take or Pay              *       *
Capacity                 

Base Capacity            *       *       *       *       *
(For Options)

X% of Base              90%     80%     70%     60%     50%
Capacity

Option I                 *       *       *       *
Capacity

Option II                        *       *       *       *
Capacity

TSMC Committed           *       *       *       *       *
Capacity (Base
Capacity + Option
Capacity)

Customer Committed       *       *       *       *       *
Capacity (X% Base
Capacity + Option
Capacity)


Deposits Required:

        Option I   -    At contract signing  ***

        Option II  -    June 30, 1996        ***


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                                 Exhibit B1
                        WAFER EQUIVALENT CALCULATION

TO CALCULATE THE WEIGHTED CAPACITY FACTOR



                                                                                               WEIGHTED
                                         CAPACITY           WAFER          PERCENTAGE          CAPACITY
PROCESS                                   FACTOR          CAPACITY         OF VOLUME            FACTOR
                                                                                   

 .8um SPDM                                   *                *                 *                   *

 .6um SPTM                                   *                *                 *                   *

TOTAL VOLUME                                *                *                 *                   *

1996 WEIGHTED CAPACITY FACTOR                                                                      *

 .6um SPTM                                   *                *                 *                   *

TOTAL VOLUME                                                 *                 *                   *

1997 WEIGHTED CAPACITY FACTOR                                                                      *

TO CALCULATE THE EQUIVALENT CAPACITY

1997 COMMITTED CAPACITY                                                        *

1997 EQUIVALENT CAPACITY                   ***                                 *


1997 EQUIVALENT CAPACITY = (1996 WEIGHTED CAPACITY FACTOR/1997 WEIGHTED
                           CAPACITY FACTOR) * 1997 COMMITTED CAPACITY
   
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                                   Exhibit C
                            TSMC TECHNOLOGY ROAD MAP


                          TSMC CMOS Technology Roadmap


MIXED                   0.6um           0.5um           0.35um
MODE                    2P3M            2P3M            2P4M
                                                        3V
                                         3V


LOGIC                   0.6um           0.5um           0.35um
                        1P3M            1P3M            1P4M
                                                        3V
                                           1P3M
                                            3V

SRAM                0.6um     0.5um    0.45um     0.35um
                                                    3V
                                3V       3V                   


                        Q1 Q2 Q3 Q4
                             *          *          *         *         *

                        
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                                   EXHIBIT D
                             OPTION FEE (OPTION II)


   Year         Option Capacity         Option Fee              Due Date
Established      (Unit: Wafer           (Unit: US$)     
                  Equivalent)

   *                  *                     *                      *


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                                   EXHIBIT E

                        STANDARD FORM OF PROMISSORY NOTE

Amount:  ***                            Due Date: June 30, 1996


        The undersigned, Adaptec manufacturing (S) Ptd. Ltd. (the "Maker"), 
unconditionally promise to pay to Taiwan Semiconductor Manufacturing Co., Ltd., 
or its order the sum of             ******                 , plus interest 
calculated from the due date stated herein to the date of full payment at the 
rate  *  per annum on any unpaid portion of the principal amount stated herein, 
and said payment will be made to such account as Maker may direct.

        This Note shall be governed in all respects by the laws of the State of
California.

        The Maker of this Note agrees to waive protests and notice of whatever 
kind in connection with the delivery, acceptance, performance, default or 
enforcement of this Note.

Issue Dated:  October __, 1995

Issue Place:  Singapore

                                        By: ______________________

                                        Title: ______________________________

                                        Adaptec Manufacturing (S) Pte. Ltd.
                                        6 Bartery Road. 530-00
                                        Singapore 049909

                      

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