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                                                                     EXHIBIT 4.2

                               KOMAG, INCORPORATED

             AMENDED AND RESTATED 2002 EMPLOYEE STOCK PURCHASE PLAN

                              (AS OF MAY 20, 2003)

         The following constitutes the provisions of the Amended and Restated
2002 Employee Stock Purchase Plan of Komag, Incorporated.

         1. Purpose. The purpose of the Plan is to provide Employees with an
opportunity to purchase Common Stock 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 Code. The provisions of the Plan,
accordingly, shall be construed so as to extend and limit Plan participation in
a manner that is consistent with the requirements of that section of the Code.

         2. Definitions.

                  (a) "Administrator" means the Board or any committee thereof
designated by the Board in accordance with Section 14.

                  (b) "Board" means the Board of Directors of the Company.

                  (c) "Change of Control" means the occurrence of any of the
following events:

                           (i)      Any "person" (as such term is used in
Sections 13(d) and 14(d) of the Exchange Act) becomes the "beneficial owner" (as
defined in Rule 13d-3 of the Exchange Act), directly or indirectly, of
securities of the Company representing fifty percent (50%) or more of the total
voting power represented by the Company's then outstanding voting securities; or

                           (ii)     The consummation of the sale or disposition
by the Company of all or substantially all of the Company's assets; or

                           (iii)    The consummation of a merger or
consolidation of the Company, with any other corporation, other than a merger or
consolidation which would result in the voting securities of the Company
outstanding immediately prior thereto continuing to represent (either by
remaining outstanding or by being converted into voting securities of the
surviving entity or its parent) at least fifty percent (50%) of the total voting
power represented by the voting securities of the Company, or such surviving
entity or its parent outstanding immediately after such merger or consolidation.

                           (iv)     A change in the composition of the Board, as
a result of which fewer than a majority of the Directors are Incumbent
Directors. "Incumbent Directors" means Directors who either (A) are Directors as
of the effective date of the Plan (pursuant to Section 23), or (B) are elected,
or nominated for election, to the Board with the affirmative votes of at least a
majority of those Directors whose election or nomination was not in connection
with any transaction described

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in subsections (i), (ii) or (iii) or in connection with an actual or threatened
proxy contest relating to the election of Directors of the Company.

                  (d) "Code" means the Internal Revenue Code of 1986, as
amended. Any reference to a section of the Code herein shall be a reference to
any successor or amended section of the Code.

                  (e) "Common Stock" means the common stock of the Company.

                  (f) "Company" means Komag, Incorporated, a Delaware
corporation.

                  (g) "Compensation" means an Employee's base pay, all overtime,
and 2003 Bonus Plan but exclusive of payments for 2003 Target Incentive Plan,
shift premium, commissions and other compensation. Prior to an Offering Period,
the Administrator may determine that additional items of compensation shall be
included or excluded from the definition of Compensation for that Offering
Period.

                  (h) "Designated Subsidiary" means any Subsidiary that has been
designated by the Administrator from time to time in its sole discretion as
eligible to participate in the Plan.

                  (i) "Director" means a member of the Board.

                  (j) "Employee" means any individual who is a common law
employee of an Employer and is customarily employed for at least twenty (20)
hours per week and more than five (5) months in any calendar year by the
Employer. 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 Employer. Where the period of leave exceeds ninety (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.

                  (k) "Employer" means any one or all of the Company and its
Designated Subsidiaries.

                  (l) "Enrollment Date" means the first Trading Day of each
Offering Period.

                  (m) "Exchange Act" means the Securities Exchange Act of 1934,
as amended, including the rules and regulations promulgated thereunder.

                  (n) "Exercise Date" means the last Trading Day at or before
the last day of fiscal month of February and August of each year. Prior to an
Offering Period, the Administrator may change the Exercise Date(s) for that
Offering Period. The first Exercise Date under the Plan shall be the last
Trading Day before the end of fiscal month of August, 2003, unless otherwise
determined by the Administrator.

                  (o) "Fair Market Value" means, 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

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SmallCap Market of The Nasdaq Stock Market, its Fair Market Value shall be the
closing sales price for the Common Stock (or the closing bid, if no sales were
reported) as quoted on such exchange or system on the date of determination, as
reported in The Wall Street Journal or such other source as the Administrator
deems reliable, or;

                           (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 on the date of determination, as reported in The Wall Street
Journal or such other source as the Administrator deems reliable, or;

                           (iii)    In the absence of an established market for
the Common Stock, its Fair Market Value shall be determined in good faith by the
Administrator.

                  (p) "Offering Periods" means the periods of approximately six
(6) months during which an option granted pursuant to the Plan may be exercised,
commencing on the first Trading Day of the fiscal month of March and September
of each year and terminating on the last Trading Day of the fiscal month of
August and February of each year. The duration and timing of Offering Periods
may be changed pursuant to Section 4 of this Plan.

                  (q) "Parent" means a "parent corporation," whether now or
hereafter existing, as defined in Section 424(e) of the Code.

                  (r) "Plan" means this Amended and Restated 2002 Employee Stock
Purchase Plan.

                  (s) "Purchase Period" means the approximately six (6) month
period commencing on the next trading day following 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.

                  (t) "Purchase Price" means an amount equal to eighty-five
percent (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 Administrator pursuant to Section
20.

                  (u) "Subsidiary" means a "subsidiary corporation," whether now
or hereafter existing, as defined in Section 424(f) of the Code.

                  (v) "Trading Day" means a day on which the U.S. national stock
exchanges and the Nasdaq System are open for trading.

         3. Eligibility.

                  (a) General. Any individual who is an Employee as of the
Enrollment Date of any Offering Period shall be eligible to participate in such
Offering Period, subject to the requirements of Section 5.

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                  (b) Limitations. 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 or any Parent or Subsidiary 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 Parent or Subsidiary of
the Company, or (ii) to the extent that his or her rights to purchase stock
under all employee stock purchase plans (as defined in Section 423 of the Code)
of the Company or any Parent or Subsidiary of the Company accrues at a rate
which exceeds twenty-five thousand dollars ($25,000) worth of stock (determined
at the Fair Market Value of the stock 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 (and
if determined by the Administrator, overlapping) Offering Periods with a new
Offering Period commencing on the first Trading Day of the fiscal month of March
and September of each year, or on such other dates as the Administrator shall
determine, and continuing thereafter until terminated in accordance with Section
20. The Administrator shall have the power to change the duration of Offering
Periods (including the commencement dates thereof) with respect to future
offerings without stockholder approval if such change is announced prior to the
scheduled beginning of the first Offering Period to be affected thereafter.

         5. Participation. An Employee who is eligible to participate in the
Plan pursuant to Section 3(b) may become a participant by (i) submitting to the
Company's payroll office (or its designee), on or before a date prescribed by
the Administrator prior to an applicable Enrollment Date, a properly completed
subscription agreement authorizing payroll deductions in the form provided by
the Administrator for such purpose, or (ii) following an electronic or other
enrollment procedure prescribed by the Administrator.

         6. Payroll Deductions.

                  (a) At the time a participant enrolls in the Plan pursuant to
Section 5, he or she shall elect to have payroll deductions made on each payday
during the Offering Period in an amount not exceeding 10% of the Compensation
which he or she receives on each such payday. Prior to the commencement of an
Offering Period, the Administrator may change the maximum amount of Compensation
that may be contributed under the Plan for that Offering Period.

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

                  (c) 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.

                  (d) A participant may discontinue his or her participation in
the Plan as provided in Section 10, or may either increase or decrease the rate
of his or her payroll deductions during the Offering Period by (i) properly
completing and submitting to the Company's payroll office (or its

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designee), on or before a date prescribed by the Administrator prior to an
applicable Exercise Date, a new subscription agreement authorizing the change in
payroll deduction rate in the form provided by the Administrator for such
purpose, or (ii) following an electronic or other procedure prescribed by the
Administrator; provided, however, that a participant may only make one payroll
deduction change during each Purchase Period. If a participant has not followed
such procedures to change the rate of payroll deductions, the rate of his or her
payroll deductions shall continue at the originally elected rate throughout the
Offering Period and future Offering Periods (unless terminated as provided in
Section 10). The Administrator may, in its sole discretion, limit the nature
and/or number of payroll deduction rate changes that may be made by participants
during any Offering Period. Any change in payroll deduction rate made pursuant
to this Section 6(d) shall be effective as of the first full payroll period
following five (5) business days after the date on which the change is made by
the participant (unless the Administrator, in its sole discretion, elects to
process a given change in payroll deduction rate more quickly).

                  (e) Notwithstanding the foregoing, to the extent necessary to
comply with Section 423(b)(8) of the Code and Section 3(b), 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 originally
elected by the participant effective as of 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.

                  (f) 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 the sale or early disposition of
Common Stock by the Employee.

         7. Grant of Option. On the Enrollment Date of each Offering Period,
each 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 Common Stock determined by dividing
such participant'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 a participant be
permitted to purchase during each Purchase Period more than 250 shares of Common
Stock and the aggregate number of shares purchased during any Purchase Period
may not exceed 150,000 shares (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 13. The Employee may accept the grant of such
option by electing to participate in the Plan in accordance with the
requirements of Section 5. The Administrator may, for future Offering Periods,
increase or decrease, in its absolute discretion, the maximum number of shares
of Common Stock that a participant may purchase during each Purchase Period of
such Offering Period. Exercise of the option shall occur as provided in Section
8, unless the participant has withdrawn pursuant to Section 10. The option shall
expire on the last day of the Offering Period.

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         8. Exercise of Option.

                  (a) Unless a participant withdraws from the Plan as provided
in Section 10, his or her option for the purchase of shares of Common Stock
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
account. No fractional shares of Common Stock 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. 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) Notwithstanding any contrary Plan provision, if the
Administrator determines that, on a given Exercise Date, the number of shares of
Common Stock 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 of Common Stock available for sale under the Plan on such Exercise Date,
the Administrator 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 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 terminate
any or all Offering Periods then in effect pursuant to Section 20. The Company
may make pro rata allocation of the shares of Common Stock available on the
Enrollment Date of any applicable Offering Period pursuant to the preceding
sentence, notwithstanding any authorization of additional shares of Common Stock
for issuance under the Plan by the Company's shareholders subsequent to such
Enrollment Date.

         9. Delivery. As soon as administratively practicable after each
Exercise Date on which a purchase of shares of Common Stock occurs, the Company
shall arrange the delivery to each participant, as appropriate, the shares
purchased upon exercise of his or her option in a form determined by the
Administrator (in its sole discretion) and pursuant to rules established by the
Administrator. No participant shall have any voting, dividend, or other
shareholder rights with respect to shares of Common Stock subject to any option
granted under the Plan until such shares have been purchased and delivered to
the participant as provided in this Section 9.

         10. Withdrawal.

                  (a) Under procedures established by the Administrator, 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 (i) submitting to the Company's payroll office (or
its designee) a written notice of withdrawal in the form prescribed by the
Administrator for

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such purpose, or (ii) following an electronic or other withdrawal procedure
prescribed by the Administrator. All of the participant's payroll deductions
credited to his or her account shall be paid to such participant as promptly as
practicable after the effective date of his or her 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 re-enrolls in the Plan in accordance with the
provisions of Section 5.

                  (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.

         11. Termination of Employment. Upon a participant's ceasing to be an
Employee for any reason other than his or her death, he or she shall be deemed
to have elected to withdraw from the Plan, the participant's option shall be
automatically terminated and the payroll deductions credited to the
participant's account during the Offering Period but not yet used to purchase
shares of Common Stock under the Plan shall be returned to him or her. 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. If within 90 days before an Exercise Date, a participant ceases to be an
Employee due to his or her death, then the payroll deductions credited to the
participant's account during the Offering Period but not yet used to purchase
shares of Common Stock under the Plan shall be used to purchase shares on such
Exercise Date unless the person or persons entitled under Section 15 to any cash
accumulated by the participant prior to his or her death elect otherwise in such
manner as the Administrator may specify. If more than 90 days before an Exercise
Date, a participant ceases to be an Employee due to his or her death, or the
person or persons entitled under Section 15 to any cash accumulated by a
deceased participant elect to withdraw from the Plan pursuant to the preceding
sentence, then the participant's option shall be automatically terminated and
the payroll deductions credited to the participant's account during the Offering
Period but not yet used to purchase shares of Common Stock under the Plan shall
not be used to purchase Common Stock and instead shall be distributed pursuant
to Section 15.

         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, the maximum number of shares of Common
Stock which shall be made available for sale under the Plan shall be 600,000.

                  (b) Shares of Common Stock 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.

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         14. Administration. The Plan shall be administered by the Board or a
committee of members of the Board who shall be appointed from time to time by,
and shall serve at the pleasure of, the Board. The Administrator 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. The Administrator, in its sole discretion and on such
terms and conditions as it may provide, may delegate to one or more individuals
all or any part of its authority and powers under the Plan. Every finding,
decision and determination made by the Administrator (or its designee) shall, to
the full extent permitted by law, be final and binding upon all parties.

         15. Designation of Beneficiary.

                  (a) A participant may designate a beneficiary who, following
the participant's death, is to receive any shares of Common Stock and/or cash
credited to the participant's account under the Plan but not yet distributed to
the participant. The designated beneficiary (or other person described in
Section 15(b)) also shall have the rights described in Section 11 in the event
of the participant's death. 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. 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 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.

                  (c) All beneficiary designations under this Section 15 shall
be made in such form and manner as the Administrator may prescribe from time to
time.

         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 of Common Stock 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) 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 from an Offering Period in accordance with Section 10.

         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. Until
shares of Common Stock are issued under the Plan (as evidenced by the
appropriate entry on the books of the Company or of a duly authorized transfer
agent of the Company), a participant shall only have the rights of an unsecured
creditor with respect to such shares.

         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

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shall set forth the amounts of payroll deductions, the Purchase Price, the
number of shares of Common Stock purchased and the remaining cash balance, if
any.

         19. Adjustments, Dissolution, Liquidation or Change of Control.

                  (a) Adjustments. In the event that any dividend or other
distribution (whether in the form of cash, Common Stock, other securities, or
other property), recapitalization, stock split, reverse stock split,
reorganization, merger, consolidation, split-up, spin-off, combination,
repurchase, or exchange of Common Stock or other securities of the Company, or
other change in the corporate structure of the Company affecting the Common
Stock such that an adjustment is determined by the Administrator (in its sole
discretion) to be appropriate in order to prevent dilution or enlargement of the
benefits or potential benefits intended to be made available under the Plan,
then the Administrator shall, in such manner as it may deem equitable, adjust
the number and class of Common Stock which may be delivered under the Plan, the
Purchase Price per share and the number of shares of Common Stock covered by
each option under the Plan which has not yet been exercised, and the numerical
limits of Sections 7 and 13.

                  (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 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.

                  (c) Change of Control. In the event of a Change of Control,
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 Change of
Control. 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.

         20. Amendment or Termination.

                  (a) The Administrator may at any time and for any reason
terminate or amend the Plan. Except as provided in Section 19, no such
termination can affect options previously granted under the Plan, provided that
an Offering Period may be terminated by the Administrator on any Exercise Date
if the Administrator determines that the termination of the Plan is in the best
interests of the Company and its stockholders. Except as provided in Section 19
and this Section 20, no amendment may make any change in any option theretofore
granted which adversely affects the

                                      -9-

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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 stockholder
approval in such a manner and to such a degree as required.

                  (b) Without stockholder consent and without regard to whether
any participant rights may be considered to have been "adversely affected," the
Administrator 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 Administrator determines in its sole discretion advisable which are
consistent with the Plan.

                  (c) In the event the Administrator 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:

                           (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 of Common Stock shall
not be issued with respect to an option under the Plan 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, including the rules
and regulations promulgated thereunder, the Exchange Act 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

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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 or its approval by the stockholders of the
Company. It shall continue in effect until terminated under Section 20.

         24. Automatic Transfer to Low Price Offering Period. If the
Administrator has specified overlapping Offering Periods, then 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.

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                          SAMPLE SUBSCRIPTION AGREEMENT

                               KOMAG, INCORPORATED

             AMENDED AND RESTATED 2002 EMPLOYEE STOCK PURCHASE PLAN

                             SUBSCRIPTION AGREEMENT

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

1.       ____________________ hereby elects to participate in the Komag,
         Incorporated Amended and Restated 2002 Employee Stock Purchase Plan
         (the "Plan") and subscribes to purchase shares of the Company's Common
         Stock in accordance with this Subscription Agreement and the Plan.

2.       I hereby authorize payroll deductions from each paycheck in the amount
         of ____% of my Compensation on each payday (from 1 to 10%) during the
         Offering Period in accordance with the 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 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 Plan. I understand that my
         participation in the 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
         Plan.

5.       Shares of Common Stock purchased for me under the 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 Offering 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 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

<PAGE>

         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 Plan. The effectiveness
         of this Subscription Agreement is dependent upon my eligibility to
         participate in the Plan.

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

         NAME: (please print) __________________________________________________
                                    (First)           (Middle)         (Last)

         ____________________        ___________________________________________
         Relationship

         ____________________        ___________________________________________
         Percentage Benefit          (Address)

         NAME: (please print) __________________________________________________
                                    (First)           (Middle)         (Last)

         ____________________        ___________________________________________
         Relationship

         _____________________       ___________________________________________
         Percentage of Benefit       (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

Dated:_________________________       ____________________________________
                                      Spouse's Signature (If beneficiary other
                                      than spouse)

                                      -3-

<PAGE>

                            SAMPLE WITHDRAWAL NOTICE

                               KOMAG, INCORPORATED

             AMENDED AND RESTATED 2002 EMPLOYEE STOCK PURCHASE PLAN

                              NOTICE OF WITHDRAWAL

         The undersigned participant in the Offering Period of the Komag,
Incorporated Amended and Restated 2002 Employee Stock Purchase Plan which began
on ____________, ______ (the "Offering 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:

                                      ________________________________

                                      ________________________________

                                      ________________________________

                                      Signature:

                                      ________________________________

                                      Date:____________________________