<PAGE>

                                  ADAPTEC, INC.

                        1986 EMPLOYEE STOCK PURCHASE PLAN

                (amended and restated June 1998 and August 2000)


         The following constitute the provisions of the 1986 Employee Stock
Purchase Plan of Adaptec, Inc.

         1.     PURPOSE. The purpose of the Plan is to provide employees of the
Company and its Designated Subsidiaries with an opportunity to purchase Common
Stock of the Company through accumulated payroll deductions. It is the intention
of the Company to have the Plan qualify as an "Employee Stock Purchase Plan"
under Section 423 of the Internal Revenue Code of 1986, as amended. The
provisions of the Plan, accordingly, shall be construed so as to extend and
limit participation in a manner consistent with the requirements of that section
of the Code.

         2.     DEFINITIONS.

                (a)     "BOARD" shall mean the Board of Directors of the Company
or any committee thereof designated by the Board of Directors of the Company in
accordance with Section 14 of the Plan.

                (b)     "CODE" shall mean the Internal Revenue Code of 1986, as
amended.

                (c)     "COMMON STOCK" shall mean the common stock of the
Company.

                (d)     "COMPANY" shall mean Adaptec, Inc. and any Designated
Subsidiary of the Company.

                (e)     "COMPENSATION" shall mean all base straight time gross
earnings and commissions, but exclusive of payments for overtime, shift premium,
incentive compensation, incentive payments, bonuses and other compensation.

                (f)     "DESIGNATED SUBSIDIARY" shall mean any Subsidiary that
has been designated by the Board from time to time in its sole discretion as
eligible to participate in the Plan.

                (g)     "EMPLOYEE" shall mean any individual who is an Employee
of the Company for tax purposes whose customary employment with the Company is
at least twenty (20) hours per week and more than five (5) months in any
calendar year. For purposes of the Plan, the employment relationship shall be
treated as continuing intact while the individual is on sick leave or other
leave of absence approved by the Company. Where the period of leave exceeds 90
days and the individual's right to reemployment is not guaranteed either by
statute or by contract, the employment relationship shall be deemed to have
terminated on the 91st day of such leave.

                (h)     "ENROLLMENT DATE" shall mean the first Trading Day of
each Offering Period.
<PAGE>


                (i)     "EXERCISE DATE" shall mean the last Trading Day of each
Purchase Period.

                (j)     "FAIR MARKET VALUE" shall mean, as of any date, the
value of Common Stock determined as follows:

                        (i)     If the Common Stock is listed on any established
stock exchange or a national market system, including without limitation the
Nasdaq National Market or The Nasdaq SmallCap Market of The Nasdaq Stock Market,
its Fair Market Value shall be the closing sales price for such stock (or the
closing bid, if no sales were reported) as quoted on such exchange or system for
the last market trading day on the date of such determination, as reported in
THE WALL STREET JOURNAL or such other source as the Board deems reliable;

                        (ii)    If the Common Stock is regularly quoted by a
recognized securities dealer but selling prices are not reported, its Fair
Market Value shall be the mean of the closing bid and asked prices for the
Common Stock prior to the date of determination, as reported in THE WALL STREET
JOURNAL or such other source as the Board deems reliable;

                        (iii)   In the absence of an established market for the
Common Stock, the Fair Market Value thereof shall be determined in good faith by
the Board; or

                (k)     "OFFERING PERIODS" shall mean the periods of
approximately twenty-four (24) months during which an option granted pursuant to
the Plan may be exercised, commencing on the first Trading Day on or after
February 15 and August 15 of each year and terminating on the last Trading Day
in the periods ending twenty-four (24) months later. The duration and timing of
Offering Periods may be changed pursuant to Section 4 of this Plan.

                (l)     "PLAN" shall mean this Employee Stock Purchase Plan.

                (m)     "PURCHASE PERIOD" shall mean the approximately six (6)
month period commencing after one Exercise Date and ending with the next
Exercise Date, except that the first Purchase Period of any Offering Period
shall commence on the Enrollment Date and end with the next Exercise Date.

                (n)     "PURCHASE PRICE" shall mean 85% of the Fair Market Value
of a share of Common Stock on the Enrollment Date or on the Exercise Date,
whichever is lower; provided however, that the Purchase Price may be adjusted by
the Board pursuant to Section 20.

                (o)     "RESERVES" shall mean the number of shares of Common
Stock covered by each option under the Plan which have not yet been exercised
and the number of shares of Common Stock which have been authorized for issuance
under the Plan but not yet placed under option.

                (p)     "SUBSIDIARY" shall mean a corporation, domestic or
foreign, of which not less than 50% of the voting shares are held by the Company
or a Subsidiary, whether or not such corporation now exists or is hereafter
organized or acquired by the Company or a Subsidiary.

                (q)     "TRADING DAY" shall mean a day on which national stock
exchanges and the Nasdaq System are open for trading.

                                      -2-
<PAGE>

         3.     ELIGIBILITY.

                (a)    Any Employee who shall be employed by the Company on a
given Enrollment Date shall be eligible to participate in the Plan.

                (b)    Any provisions of the Plan to the contrary
notwithstanding, no Employee shall be granted an option under the Plan (i) to
the extent that, immediately after the grant, such Employee (or any other
person whose stock would be attributed to such Employee pursuant to Section
424(d) of the Code) would own capital stock of the Company and/or hold
outstanding options to purchase such stock possessing five percent (5%) or
more of the total combined voting power or value of all classes of the
capital stock of the Company or of any Subsidiary, or (ii) to the extent that
his or her rights to purchase stock under all employee stock purchase plans
of the Company and its subsidiaries accrues at a rate which exceeds
Twenty-Five Thousand Dollars ($25,000) worth of stock (determined at the fair
market value of the shares at the time such option is granted) for each
calendar year in which such option is outstanding at any time.

         4.     OFFERING PERIODS. The Plan shall be implemented by consecutive,
overlapping Offering Periods with a new Offering Period commencing on the first
Trading Day on or after February 15 and August 15 each year, or on such other
date as the Board shall determine, and continuing thereafter until terminated in
accordance with Section 20 hereof. The Board shall have the power to change the
duration of Offering Periods (including the commencement dates thereof) with
respect to future offerings without shareholder approval if such change is
announced at least five (5) days prior to the scheduled beginning of the first
Offering Period to be affected thereafter.

         5.      PARTICIPATION.

                (a)     An eligible Employee may become a participant in the
Plan by completing a subscription agreement authorizing payroll deductions in
the form of Exhibit A to this Plan and filing it with the Company's payroll
office prior to the applicable Enrollment Date; provided however, that for the
Offering Period beginning August 15, 2000 only, such subscription agreement may
be filed with the Company's payroll office within such period, applied on a
uniform and nondiscriminatory basis, as the Company may announce.

                (b)     Payroll deductions for a participant shall commence on
the first payroll following the Enrollment Date and shall end on the last
payroll in the Offering Period to which such authorization is applicable, unless
sooner terminated by the participant as provided in Section 10 hereof.

         6.     PAYROLL DEDUCTIONS.

                (a)     At the time a participant files his or her subscription
agreement, he or she shall elect to have payroll deductions made on each pay day
during the Offering Period in an amount not less than three percent (3%) and not
exceeding ten percent (10%) of the Compensation which he or she receives on each
pay day during the Offering Period.

                (b)     All payroll deductions made for a participant shall be
credited to his or her account under the Plan and shall be withheld in whole
percentages only. A participant may not make any additional payments into such
account.

                                      -3-
<PAGE>

                (c)     A participant may discontinue his or her participation
in the Plan as provided in Section 10 hereof, or may increase or decrease the
rate of his or her payroll deductions during the Offering Period by completing
or filing with the Company a new subscription agreement authorizing a change in
payroll deduction rate. The Board may, in its discretion, limit the number of
participation rate changes during any Offering Period. The change in rate shall
be effective with the first full payroll period following five (5) business days
after the Company's receipt of the new subscription agreement unless the Company
elects to process a given change in participation more quickly. A participant's
subscription agreement shall remain in effect for successive Offering Periods
unless terminated as provided in Section 10 hereof.

                (d)     Notwithstanding the foregoing, to the extent necessary
to comply with Section 423(b)(8) of the Code and Section 3(b) hereof, a
participant's payroll deductions may be decreased to zero percent (0%) at any
time during a Purchase Period. Payroll deductions shall recommence at the rate
provided in such participant's subscription agreement at the beginning of the
first Purchase Period which is scheduled to end in the following calendar year,
unless terminated by the participant as provided in Section 10 hereof.

                (e)     At the time the option is exercised, in whole or in
part, or at the time some or all of the Company's Common Stock issued under the
Plan is disposed of, the participant must make adequate provision for the
Company's federal, state, or other tax withholding obligations, if any, which
arise upon the exercise of the option or the disposition of the Common Stock. At
any time, the Company may, but shall not be obligated to, withhold from the
participant's compensation the amount necessary for the Company to meet
applicable withholding obligations, including any withholding required to make
available to the Company any tax deductions or benefits attributable to sale or
early disposition of Common Stock by the Employee.

         7.     GRANT OF OPTION. On the Enrollment Date of each Offering Period,
each eligible Employee participating in such Offering Period shall be granted an
option to purchase on each Exercise Date during such Offering Period (at the
applicable Purchase Price) up to a number of shares of the Company's Common
Stock determined by dividing such Employee's payroll deductions accumulated
prior to such Exercise Date and retained in the Participant's account as of the
Exercise Date by the applicable Purchase Price; provided that in no event shall
an Employee be permitted to purchase during each Purchase Period more than 5,000
shares of the Company's Common Stock (subject to any adjustment pursuant to
Section 19), and provided further that such purchase shall be subject to the
limitations set forth in Sections 3(b) and 12 hereof. The Board may, for future
Offering Periods, increase or decrease, in its absolute discretion, the maximum
number of shares of the Company's Common Stock an Employee may purchase during
each Purchase Period of such Offering Period. Exercise of the option shall occur
as provided in Section 8 hereof, unless the participant has withdrawn pursuant
to Section 10 hereof. The option shall expire on the last day of the Offering
Period.

         8.     EXERCISE OF OPTION.

                (a)     Unless a participant withdraws from the Plan as provided
in Section 10 hereof, his or her option for the purchase of shares shall be
exercised automatically on the Exercise Date, and the maximum number of full
shares subject to option shall be purchased for such participant at the
applicable Purchase Price with the accumulated payroll deductions in his or her

                                      -4-
<PAGE>

account. No fractional shares shall be purchased; any payroll deductions
accumulated in a participant's account which are not sufficient to purchase a
full share shall be retained in the participant's account for the subsequent
Purchase Period or Offering Period, subject to earlier withdrawal by the
participant as provided in Section 10 hereof. Any other monies left over in a
participant's account after the Exercise Date shall be returned to the
participant. During a participant's lifetime, a participant's option to purchase
shares hereunder is exercisable only by him or her.

                (b)     If the Board determines that, on a given Exercise Date,
the number of shares with respect to which options are to be exercised may
exceed (i) the number of shares of Common Stock that were available for sale
under the Plan on the Enrollment Date of the applicable Offering Period, or (ii)
the number of shares available for sale under the Plan on such Exercise Date,
the Board may in its sole discretion (x) provide that the Company shall make a
pro rata allocation of the shares of Common Stock available for purchase on such
Enrollment Date or Exercise Date, as applicable, in as uniform a manner as shall
be practicable and as it shall determine in its sole discretion to be equitable
among all participants exercising options to purchase Common Stock on such
Exercise Date, and continue all Offering Periods then in effect, or (y) provide
that the Company shall make a pro rata allocation of the shares available for
purchase on such Enrollment Date or Exercise Date, as applicable, in as uniform
a manner as shall be practicable and as it shall determine in its sole
discretion to be equitable among all participants exercising options to purchase
Common Stock on such Exercise Date, and terminate any or all Offering Periods
then in effect pursuant to Section 20 hereof. The Company may make pro rata
allocation of the shares available on the Enrollment Date of any applicable
Offering Period pursuant to the preceding sentence, notwithstanding any
authorization of additional shares for issuance under the Plan by the Company's
shareholders subsequent to such Enrollment Date.

         9.     DELIVERY. As promptly as practicable after each Exercise Date on
which a purchase of shares occurs, the Company shall arrange the delivery to
each participant, as appropriate, the shares purchased upon exercise of his or
her option.

         10.    WITHDRAWAL.

                (a)     A participant may withdraw all but not less than all the
payroll deductions credited to his or her account and not yet used to exercise
his or her option under the Plan at any time by giving written notice to the
Company in the form of Exhibit B to this Plan. All of the participant's payroll
deductions credited to his or her account shall be paid to such participant
promptly after receipt of notice of withdrawal and such participant's option for
the Offering Period shall be automatically terminated, and no further payroll
deductions for the purchase of shares shall be made for such Offering Period. If
a participant withdraws from an Offering Period, payroll deductions shall not
resume at the beginning of the succeeding Offering Period unless the participant
delivers to the Company a new subscription agreement.

                (b)     A participant's withdrawal from an Offering Period shall
not have any effect upon his or her eligibility to participate in any similar
plan which may hereafter be adopted by the Company or in succeeding Offering
Periods which commence after the termination of the Offering Period from which
the participant withdraws.

                                      -5-
<PAGE>

         11.    TERMINATION OF EMPLOYMENT.

                Upon a participant's ceasing to be an Employee, for any reason,
he or she shall be deemed to have elected to withdraw from the Plan and the
payroll deductions credited to such participant's account during the Offering
Period but not yet used to exercise the option shall be returned to such
participant or, in the case of his or her death, to the person or persons
entitled thereto under Section 15 hereof, and such participant's option shall be
automatically terminated. The preceding sentence notwithstanding, a participant
who receives payment in lieu of notice of termination of employment shall be
treated as continuing to be an Employee for the participant's customary number
of hours per week of employment during the period in which the participant is
subject to such payment in lieu of notice.

         12.    INTEREST. No interest shall accrue on the payroll deductions of
a participant in the Plan.

         13.    STOCK.

                (a)     Subject to adjustment upon changes in capitalization of
the Company as provided in Section 19 hereof, the maximum number of shares of
the Company's Common Stock which shall be made available for sale under the Plan
shall be 10,600,000 shares.

                (b)     The participant shall have no interest or voting right
in shares covered by his option until such option has been exercised.

                (c)     Shares to be delivered to a participant under the Plan
shall be registered in the name of the participant or in the name of the
participant and his or her spouse.

         14.    ADMINISTRATION. The Plan shall be administered by the Board or a
committee of members of the Board appointed by the Board. The Board or its
committee shall have full and exclusive discretionary authority to construe,
interpret and apply the terms of the Plan, to determine eligibility and to
adjudicate all disputed claims filed under the Plan. Every finding, decision and
determination made by the Board or its committee shall, to the full extent
permitted by law, be final and binding upon all parties.

         15.    DESIGNATION OF BENEFICIARY.

                (a)     A participant may file a written designation of a
beneficiary who is to receive any shares and cash, if any, from the
participant's account under the Plan in the event of such participant's death
subsequent to an Exercise Date on which the option is exercised but prior to
delivery to such participant of such shares and cash. In addition, a participant
may file a written designation of a beneficiary who is to receive any cash from
the participant's account under the Plan in the event of such participant's
death prior to exercise of the option. If a participant is married and the
designated beneficiary is not the spouse, spousal consent shall be required for
such designation to be effective.

                (b)     Such designation of beneficiary may be changed by the
participant at any time by written notice. In the event of the death of a
participant and in the absence of a beneficiary validly designated under the
Plan who is living at the time of such participant's death, the Company

                                      -6-
<PAGE>

shall deliver such shares and/or cash to the executor or administrator of the
estate of the participant, or if no such executor or administrator has been
appointed (to the knowledge of the Company), the Company, in its discretion, may
deliver such shares and/or cash to the spouse or to any one or more dependents
or relatives of the participant, or if no spouse, dependent or relative is known
to the Company, then to such other person as the Company may designate.

         16.    TRANSFERABILITY. Neither payroll deductions credited to a
participant's account nor any rights with regard to the exercise of an option or
to receive shares under the Plan may be assigned, transferred, pledged or
otherwise disposed of in any way (other than by will, the laws of descent and
distribution or as provided in Section 15 hereof) by the participant. Any such
attempt at assignment, transfer, pledge or other disposition shall be without
effect, except that the Company may treat such act as an election to withdraw
funds from an Offering Period in accordance with Section 10 hereof.

         17.    USE OF FUNDS. All payroll deductions received or held by the
Company under the Plan may be used by the Company for any corporate purpose, and
the Company shall not be obligated to segregate such payroll deductions.

         18.    REPORTS. Individual accounts shall be maintained for each
participant in the Plan. Statements of account shall be given to participating
Employees at least annually, which statements shall set forth the amounts of
payroll deductions, the Purchase Price, the number of shares purchased and the
remaining cash balance, if any.

         19.    ADJUSTMENTS UPON CHANGES IN CAPITALIZATION, DISSOLUTION,
LIQUIDATION, MERGER OR ASSET SALE.

                (a)     CHANGES IN CAPITALIZATION. Subject to any required
action by the shareholders of the Company, the Reserves, the maximum number of
shares each participant may purchase each Purchase Period (pursuant to Section
7), as well as the price per share and the number of shares of Common Stock
covered by each option under the Plan which has not yet been exercised shall be
proportionately adjusted for any increase or decrease in the number of issued
shares of Common Stock resulting from a stock split, reverse stock split, stock
dividend, combination or reclassification of the Common Stock, or any other
increase or decrease in the number of shares of Common Stock effected without
receipt of consideration by the Company; provided, however, that conversion of
any convertible securities of the Company shall not be deemed to have been
"effected without receipt of consideration." Such adjustment shall be made by
the Board, whose determination in that respect shall be final, binding and
conclusive. Except as expressly provided herein, no issuance by the Company of
shares of stock of any class, or securities convertible into shares of stock of
any class, shall affect, and no adjustment by reason thereof shall be made with
respect to, the number or price of shares of Common Stock subject to an option.

                (b)     DISSOLUTION OR LIQUIDATION. In the event of the proposed
dissolution or liquidation of the Company, the Offering Period then in progress
shall be shortened by setting a new Exercise Date (the "New Exercise Date"), and
shall terminate immediately prior to the consummation of such proposed
dissolution or liquidation, unless provided otherwise by the Board. The New
Exercise Date shall be before the date of the Company's proposed dissolution or
liquidation. The Board shall notify each participant in writing, at least ten
(10) business days prior to the New Exercise Date, that the Exercise Date for
the participant's option has been changed to the

                                      -7-
<PAGE>

New Exercise Date and that the participant's option shall be exercised
automatically on the New Exercise Date, unless prior to such date the
participant has withdrawn from the Offering Period as provided in Section 10
hereof.

                (c)     MERGER OR ASSET SALE. In the event of a proposed sale of
all or substantially all of the assets of the Company, or the merger of the
Company with or into another corporation, each outstanding option shall be
assumed or an equivalent option substituted by the successor corporation or a
Parent or Subsidiary of the successor corporation. In the event that the
successor corporation refuses to assume or substitute for the option, any
Purchase Periods then in progress shall be shortened by setting a new Exercise
Date (the "New Exercise Date") and any Offering Periods then in progress shall
end on the New Exercise Date. The New Exercise Date shall be before the date of
the Company's proposed sale or merger. The Board shall notify each participant
in writing, at least ten (10) business days prior to the New Exercise Date, that
the Exercise Date for the participant's option has been changed to the New
Exercise Date and that the participant's option shall be exercised automatically
on the New Exercise Date, unless prior to such date the participant has
withdrawn from the Offering Period as provided in Section 10 hereof.

         20.    AMENDMENT OR TERMINATION.

                (a)     The Board of Directors of the Company may at any time
and for any reason terminate or amend the Plan. Except as provided in Section 19
hereof, no such termination can affect options previously granted, provided that
an Offering Period may be terminated by the Board of Directors on any Exercise
Date if the Board determines that the termination of the Offering Period or the
Plan is in the best interests of the Company and its shareholders. Except as
provided in Section 19 and this Section 20 hereof, no amendment may make any
change in any option theretofore granted which adversely affects the rights of
any participant. To the extent necessary to comply with Section 423 of the Code
(or any successor rule or provision or any other applicable law, regulation or
stock exchange rule), the Company shall obtain shareholder approval in such a
manner and to such a degree as required.

                (b)     Without shareholder consent and without regard to
whether any participant rights may be considered to have been "adversely
affected," the Board (or its committee) shall be entitled to change the Offering
Periods, limit the frequency and/or number of changes in the amount withheld
during an Offering Period, establish the exchange ratio applicable to amounts
withheld in a currency other than U.S. dollars, permit payroll withholding in
excess of the amount designated by a participant in order to adjust for delays
or mistakes in the Company's processing of properly completed withholding
elections, establish reasonable waiting and adjustment periods and/or accounting
and crediting procedures to ensure that amounts applied toward the purchase of
Common Stock for each participant properly correspond with amounts withheld from
the participant's Compensation, and establish such other limitations or
procedures as the Board (or its committee) determines in its sole discretion
advisable which are consistent with the Plan.

                (c)     In the event the Board determines that the ongoing
operation of the Plan may result in unfavorable financial accounting
consequences, the Board may, in its discretion and, to the extent necessary or
desirable, modify or amend the Plan to reduce or eliminate such accounting
consequence including, but not limited to:

                                      -8-
<PAGE>

                        (i)     altering the Purchase Price for any Offering
Period including an Offering Period underway at the time of the change in
Purchase Price;

                        (ii)    shortening any Offering Period so that Offering
Period ends on a new Exercise Date, including an Offering Period underway at the
time of the Board action; and

                        (iii)   allocating shares.

                Such modifications or amendments shall not require stockholder
approval or the consent of any Plan participants.

         21.    NOTICES. All notices or other communications by a participant to
the Company under or in connection with the Plan shall be deemed to have been
duly given when received in the form specified by the Company at the location,
or by the person, designated by the Company for the receipt thereof.

         22.    CONDITIONS UPON ISSUANCE OF SHARES. Shares shall not be issued
with respect to an option unless the exercise of such option and the issuance
and delivery of such shares pursuant thereto shall comply with all applicable
provisions of law, domestic or foreign, including, without limitation, the
Securities Act of 1933, as amended, the Securities Exchange Act of 1934, as
amended, the rules and regulations promulgated thereunder, and the requirements
of any stock exchange upon which the shares may then be listed, and shall be
further subject to the approval of counsel for the Company with respect to such
compliance.

                As a condition to the exercise of an option, the Company may
require the person exercising such option to represent and warrant at the time
of any such exercise that the shares are being purchased only for investment and
without any present intention to sell or distribute such shares if, in the
opinion of counsel for the Company, such a representation is required by any of
the aforementioned applicable provisions of law.

         23.    TERM OF PLAN. The Plan shall become effective upon the earlier
to occur of its adoption by the Board of Directors or its approval by the
shareholders of the Company. It shall continue in effect for a term of twenty
(20) years unless sooner terminated under Section 20 hereof.

         24.    AUTOMATIC TRANSFER TO LOW PRICE OFFERING PERIOD. To the extent
permitted by any applicable laws, regulations, or stock exchange rules if the
Fair Market Value of the Common Stock on any Exercise Date in an Offering Period
is lower than the Fair Market Value of the Common Stock on the Enrollment Date
of such Offering Period, then all participants in such Offering Period shall be
automatically withdrawn from such Offering Period immediately after the exercise
of their option on such Exercise Date and automatically re-enrolled in the
immediately following Offering Period as of the first day thereof.

                                      -9-
<PAGE>

                                    EXHIBIT A



                                  ADAPTEC, INC.

                        1986 EMPLOYEE STOCK PURCHASE PLAN

                (amended and restated June 1998 and August 2000)

                             SUBSCRIPTION AGREEMENT



_____ Original Application                           Enrollment Date:___________
_____ Change in Payroll Deduction Rate
_____ Change of Beneficiary(ies)


1.       ____________________ hereby elects to participate in the Adaptec, Inc.
         Employee Stock Purchase Plan (the "Employee Stock Purchase Plan") and
         subscribes to purchase shares of the Company's Common Stock in
         accordance with this Subscription Agreement and the Employee Stock
         Purchase Plan.

2.       I hereby authorize payroll deductions from each paycheck in the amount
         of ____% of my Compensation on each payday (from 3% to 10%) during the
         Offering Period in accordance with the Employee Stock Purchase Plan.
         (Please note that no fractional percentages are permitted.)

3.       I understand that said payroll deductions shall be accumulated for the
         purchase of shares of Common Stock at the applicable Purchase Price
         determined in accordance with the Employee Stock Purchase Plan. I
         understand that if I do not withdraw from an Offering Period, any
         accumulated payroll deductions will be used to automatically exercise
         my option.

4.       I have received a copy of the complete Employee Stock Purchase Plan. I
         understand that my participation in the Employee Stock Purchase Plan is
         in all respects subject to the terms of the Plan. I understand that my
         ability to exercise the option under this Subscription Agreement is
         subject to shareholder approval of the Employee Stock Purchase Plan.

5.       Shares purchased for me under the Employee Stock Purchase Plan should
         be issued in the name(s) of (Employee or Employee and Spouse only).

6.       I understand that if I dispose of any shares received by me pursuant to
         the Plan within 2 years after the Enrollment Date (the first day of the
         Offering Period during which I purchased such shares) or one year after
         the Exercise Date, I will be treated for federal income tax purposes as
         having received ordinary income at the time of such disposition in an
         amount equal to the excess of the fair market value of the shares at
         the time such shares were purchased by me over the price which I paid
         for the shares. I HEREBY AGREE TO NOTIFY THE COMPANY IN WRITING
<PAGE>

         WITHIN 30 DAYS AFTER THE DATE OF ANY DISPOSITION OF MY SHARES AND I
         WILL MAKE ADEQUATE PROVISION FOR FEDERAL, STATE OR OTHER TAX
         WITHHOLDING OBLIGATIONS, IF ANY, WHICH ARISE UPON THE DISPOSITION OF
         THE COMMON STOCK. The Company may, but will not be obligated to,
         withhold from my compensation the amount necessary to meet any
         applicable withholding obligation including any withholding necessary
         to make available to the Company any tax deductions or benefits
         attributable to sale or early disposition of Common Stock by me. If I
         dispose of such shares at any time after the expiration of the 2-year
         and 1-year holding periods, I understand that I will be treated for
         federal income tax purposes as having received income only at the time
         of such disposition, and that such income will be taxed as ordinary
         income only to the extent of an amount equal to the lesser of (1) the
         excess of the fair market value of the shares at the time of such
         disposition over the purchase price which I paid for the shares, or (2)
         15% of the fair market value of the shares on the first day of the
         Offering Period. The remainder of the gain, if any, recognized on such
         disposition will be taxed as capital gain.

7.       I hereby agree to be bound by the terms of the Employee Stock Purchase
         Plan. The effectiveness of this Subscription Agreement is dependent
         upon my eligibility to participate in the Employee Stock Purchase Plan.

8.       In the event of my death, I hereby designate the following as my
         beneficiary(ies) to receive all payments and shares due me under the
         Employee Stock Purchase Plan:


         NAME:  (Please print)
                              --------------------------------------------------
                                    (First)            (Middle)         (Last)



         -------------------------       ---------------------------------------
         Relationship
                                         ---------------------------------------
                                         (Address)



                                      -2-
<PAGE>



         Employee's Social
         Security Number:
                                        ----------------------------------------

         Employee's Address:
                                        ----------------------------------------

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

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


I UNDERSTAND THAT THIS SUBSCRIPTION AGREEMENT SHALL REMAIN IN EFFECT THROUGHOUT
SUCCESSIVE OFFERING PERIODS UNLESS TERMINATED BY ME.



Dated:
      --------------------------        ----------------------------------------
                                        Signature of Employee


                                        ----------------------------------------
                                        Spouse's Signature (If beneficiary other
                                        than spouse)



                                      -3-
<PAGE>

                                    EXHIBIT B



                                  ADAPTEC, INC.

                        1986 EMPLOYEE STOCK PURCHASE PLAN

                (amended and restated June 1998 and August 2000)

                              NOTICE OF WITHDRAWAL



         The undersigned participant in the Offering Period of the Adaptec, Inc.
1986 Employee Stock Purchase Plan which began on ____________, ______ (the
"Enrollment Date") hereby notifies the Company that he or she hereby withdraws
from the Offering Period. He or she hereby directs the Company to pay to the
undersigned as promptly as practicable all the payroll deductions credited to
his or her account with respect to such Offering Period. The undersigned
understands and agrees that his or her option for such Offering Period will be
automatically terminated. The undersigned understands further that no further
payroll deductions will be made for the purchase of shares in the current
Offering Period and the undersigned shall be eligible to participate in
succeeding Offering Periods only by delivering to the Company a new Subscription
Agreement.

                                           Name and Address of Participant:

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                                           Signature:

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                                           Date:
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