EXHIBIT 10.4.5
                      KOMAG, INCORPORATED

                  1997 SUPPLEMENTAL STOCK OPTION PLAN


        ARTICLE ONE

        GENERAL PROVISIONS


        I.      PURPOSES OF THE PLAN

                This 1997 Supplemental Stock Option Plan (the "Plan") is 
intended to promote the interests of Komag, Incorporated, a Delaware 
corporation (the "Corporation"), by providing a method whereby eligible 
individuals may be offered incentives and rewards which will encourage 
them to acquire a proprietary interest, or otherwise increase their 
proprietary interest, in the Corporation and continue to render services 
to the Corporation (or its parent or subsidiary corporations).

        II.     ADMINISTRATION OF THE PLAN 

                A.      The Plan shall be administered by one or more 
committees comprised of Board members (the "Committee") or the Board may 
retain the power to administer the Plan.  The members of the Committee 
shall each serve for such period of time as the Board may determine and 
shall be subject to removal by the Board at any time.

                B.      The Committee (or the Board if no Committee has been 
designated) shall serve as the Plan Administrator and shall have full 
power and authority (subject to the express provisions of the Plan) to 
establish such rules and regulations as it may deem appropriate for the 
proper administration of such program and to make such determinations 
under the program and any outstanding option as it may deem necessary or 
advisable.  Decisions of the Plan Administrator shall be final and 
binding on all parties with an interest in the Plan or any options or 
shares issued hereunder.

        III.    ELIGIBILITY FOR OPTION GRANTS

                A.      The persons eligible to participate in the Plan shall 
be 

                        -       employees (excluding officers and 
directors) of the Corporation (or its parent or subsidiary 
corporations),

                        -       independent contractors and consultants of 
the Corporation (or its parent or subsidiary corporations).

                B.      The Plan Administrator shall have full authority to 
select the eligible individuals who are to receive option grants under 
the Plan, the number of shares to be covered by each granted option, the 
time or times at which such option is to become exercisable and the 
maximum term for which the option is to be outstanding.

                C.      For purposes of the Plan, the following provisions 
shall be applicable in determining the parent and subsidiary corporations 
of the Corporation:

                        Any corporation (other than the Corporation) in 
an unbroken chain of corporations ending with the Corporation 
shall be considered to be a parent corporation of the 
Corporation, provided each such corporation in the unbroken 
chain (other than the Corporation) owns, at the time of the 
determination, stock possessing fifty percent (50%) or more 
of the total combined voting power of all classes of stock in 
one of the other corporations in such chain.

                        Each corporation (other than the Corporation) in 
an unbroken chain of corporations beginning with the 
Corporation shall be considered to be a subsidiary of the 
Corporation, provided each such corporation (other than the 
last corporation) in the unbroken chain owns, at the time of 
the determination, stock possessing fifty percent (50%) or 
more of the total combined voting power of all classes of 
stock in one of the other corporations in such chain.

        IV.     STOCK SUBJECT TO THE PLAN

                A.      The stock issuable under the Plan shall be shares of 
the Corporation's authorized but unissued or reacquired Common Stock.  
The aggregate number of shares which may be issued over the term of the 
Plan shall not exceed Three Million Six Hundred Thousand (3,600,000) 
shares (subject to adjustment from time to time in accordance with 
paragraph IV.C of this Article One).  
                B.      Should an option be terminated for any reason prior to 
exercise in whole or in part, the shares subject to the portion of the 
option not so exercised shall be available for subsequent option grants 
under this Plan.  In addition, unvested shares issued under the Plan and 
subsequently repurchased by the Corporation at the original exercise 
price paid per share, pursuant to the Corporation's repurchase rights 
under the Plan shall be added back to the number of shares of Common 
Stock reserved for issuance under the Plan and shall accordingly be 
available for reissuance through one or more subsequent option grants 
under the Plan.

                C.      In the event any change is made to the Common Stock 
issuable under the Plan (whether by reason of (i) merger, consolidation 
or reorganization or (ii) recapitalization, stock dividend, stock split, 
combination of shares, exchange of shares or other similar change 
affecting the outstanding Common Stock as a class without the 
Corporation's receipt of consideration), then unless such change results 
in the termination of all outstanding options pursuant to the provisions 
of paragraph II of Article Two of the Plan, appropriate adjustments shall 
be made to (i) the aggregate number and/or class of shares issuable under 
the Plan, and (ii) the number and/or class of shares and price per share 
in effect under each outstanding option under the Plan.  The purpose of 
such adjustments to the outstanding options shall be to preclude the 
enlargement or dilution of rights and benefits under such options.

        ARTICLE TWO

        OPTION GRANT PROGRAM


        I.      TERMS AND CONDITIONS OF OPTIONS



                Options granted pursuant to this Article Two shall be auth-
orized by action of the Plan Administrator and shall be Non-Statutory 
Options.  The granted options shall be evidenced by instruments in such 
form as the Plan Administrator shall from time to time approve; provided, 
however, that each such instrument shall comply with and incorporate the 
terms and conditions specified below.

                A.      Option Price.

                        1.      The option price per share shall be fixed by
the Plan Administrator.  In no event, however, shall the option price per 
share be less than one hundred percent (100%) of the fair market value 
per share of Common Stock on the date of the option grant.

                        2.      The option price shall become immediately due 
upon exercise of the option and shall be payable as follows: 

                                (i)     full payment in cash or check drawn 
to the Corporation's order;  

                                (ii)    full payment in shares of Common 
Stock held by the optionee for the requisite period necessary 
to avoid a charge to the Corporation's earnings for financial 
reporting purposes and valued at fair market value on the 
Exercise Date (as such term is defined below) equal to the 
option price; or

                                (iii)   full payment through a combination 
of shares of Common Stock held by the optionee for the 
requisite period necessary to avoid a charge to the 
Corporation's earnings for financial reporting purposes and 
valued at fair market value on the Exercise Date and cash or 
check, equal in the aggregate to the option price. 

                                (iv)    to the extent the option is 
exercised for vested shares, the option price may also be 
paid through a broker-dealer sale and remittance procedure 
pursuant to which the optionee shall provide irrevocable 
instructions to (I) a Corporation-designated brokerage firm 
to effect the immediate sale of the purchased shares and 
remit to the Corporation, out of the sale proceeds available 
on the settlement date, an amount equal to the aggregate 
option price payable for the purchased shares plus all 
applicable Federal and State income and employment taxes 
required to be withheld by the Corporation by reason of such 
purchase and (II) the Corporation to deliver the certificates 
for the purchased shares directly to such brokerage firm. 

                        For purposes of this subparagraph 2, the Exercise Date 
shall be the date on which notice of the exercise of the option is 
delivered to the Corporation.  Except to the extent the sale and 
remittance procedure is utilized in connection with the exercise of the 
option, payment of the option price for the purchased shares must 
accompany such notice.

                        3.      The fair market value of a share of Common Stock
on any relevant date under subparagraph 1 or 2 above (and for all other 
valuation purposes under the Plan) shall be determined in accordance with 
the following provisions:

                                (i)     If the Common Stock is at the time 
traded on the Nasdaq National Market, then the fair market 
value shall be the closing selling price per share of Common 
Stock on the day prior to the date in question, as such price 
is reported by the National Association of Securities Dealers 
on the Nasdaq National Market or any successor system.  If 
there is no closing selling price for the Common Stock on the 
day prior to the date in question, then the fair market value 
shall be the closing selling price on the last preceding date 
for which such quotation exists.

                                (ii)    If the Common Stock is at the time 
listed on either the New York Stock Exchange or the American 
Stock Exchange, then the fair market value shall be the 
closing selling price per share of Common Stock on the day 
prior to the date in question on such exchange, as such price 
is officially quoted in the composite tape of transactions on 
that exchange.  If there is no closing selling price for the 
Common Stock on the day prior to the date in question, then 
the fair market value shall be the closing selling price on 
the last preceding date for which such quotation exists.

                B.      Term and Exercise of Options.

                        Each option granted under this Article Two shall be 
exercisable at such time or times, during such period, and for such 
number of shares as shall be determined by the Plan Administrator and set 
forth in the instrument evidencing such option; provided, however, that 
no option granted under this Article Two shall have a maximum term in 
excess of ten (10) years from the grant date.  

                C.      Limited Transferability of Options.

                        During the lifetime of the optionee, the option shall 
be exercisable only by the optionee and shall not be assignable or 
transferable by the optionee otherwise than by will or by the laws of 
descent and distribution following the optionee's death.  However, the 
Plan Administrator may grant one or more options under this Article Two 
which may, in connection with the optionee's estate plan, be assigned in 
whole or in part during the optionee's lifetime to one or more members of 
the optionee's immediate family or to a trust established exclusively for 
one or more such family members.  The assigned portion may only be 
exercised by the person or persons who acquire a proprietary interest in 
the option pursuant to the assignment.  The terms applicable to the 
assigned portion shall be the same as those in effect for the option 
immediately prior to such assignment and shall be set forth in such 
documents issued to the assignee as the Plan Administrator may deem 
appropriate.

                D.      Termination of Service.

                        1.      Should an optionee cease to remain in Service 
for any reason (including death, permanent disability or retirement at or 
after age 65) while the holder of one or more outstanding options granted 
to such optionee under the Plan, then such option or options shall not 
(except to the extent otherwise provided pursuant to paragraph VII below) 
remain exercisable for more than a twelve (12)-month period (or such 
shorter period as is determined by the Plan Administrator and set forth 
in the option agreement) following the date of cessation of Service; 
provided, however, that under no circumstances shall any such option be 
exercisable after the specified expiration date of the option term.  
Except to the extent otherwise provided pursuant to subparagraph I.D.4 
below, each such option shall, during such twelve (12)-month or shorter 
period, be exercisable for any or all vested shares for which that option 
is exercisable on the date of such cessation of Service.  Upon the 
expiration of such twelve (12)-month or shorter period or (if earlier) 
upon the expiration of the option term, the option shall terminate and 
cease to be exercisable for any such vested shares for which the option 
has not been exercised.  However, the option shall, immediately upon the 
optionee's cessation of Service, terminate and cease to be outstanding 
with respect to any option shares in which the optionee is not otherwise 
at that time vested or for which the option is not otherwise at that time 
exercisable. 

                        2.      Should the optionee die while in Service, or 
cease to remain in Service and thereafter die while the holder of one or 
more outstanding options under the Plan, each such option may be 
exercised by the personal representative of the optionee's estate or by 
the person or persons to whom the option is transferred pursuant to the 
optionee's will or in accordance with the laws of descent and 
distribution but, except to the extent otherwise provided pursuant to 
subparagraph I.D.4 below, only to the extent of the number of vested 
shares (if any) for which the option is exercisable on the date of the 
optionee's death.  Such exercise must be effected prior to the earlier of 
(i) the first anniversary of the date of the optionee's death or (ii) the 
specified expiration date of the option term.  Upon the occurrence of the 
earlier event, the option shall terminate and cease to be exercisable.

                        3.      If (i) the optionee's Service is terminated for 
cause (including, but not limited to, any act of dishonesty, willful 
misconduct, fraud or embezzlement or any unauthorized disclosure or use 
of confidential information or trade secrets) or (ii) the optionee makes 
or attempts to make any unauthorized use or disclosure of confidential 
information or trade secrets of the Corporation or its parent or 
subsidiary corporations, then in any such event all outstanding options 
granted the optionee under the Plan shall terminate and cease to be 
exercisable immediately upon such cessation of Service or (if earlier) 
upon such unauthorized use or disclosure of confidential or secret 
information or attempt thereat.

                        4.      The Plan Administrator shall have complete 
discretion, exercisable either at the time the option is granted or at 
the time the optionee dies, retires at or after age 65, or ceases to 
remain in Service, to establish as a provision applicable to the exercise 
of one or more options granted under the Plan that during the limited 
period of exercisability following death, retirement at or after age 65, 
or cessation of Employee status as provided in subparagraph I.D.1 or 
I.D.2 above, the option may be exercised not only with respect to the 
number of vested shares for which it is exercisable at the time of the 
optionee's cessation of Service, but also with respect to one or more 
subsequent installments in which the optionee would have otherwise vested 
had such cessation of Service not occurred.

                        5.      For purposes of the foregoing provisions of
this paragraph I.D (and all other provisions of the Plan), 

                        -       The optionee shall be deemed to remain in 
the Service of the Corporation for so long as such individual 
renders services on a periodic basis to the Corporation (or 
any parent or subsidiary corporation) in the capacity of an 
Employee, a non-employee member of the Board or an 
independent consultant or advisor.

                        -       The optionee shall be considered to be an 
Employee for so long as such individual remains in the employ 
of the Corporation or one or more of its parent or subsidiary 
corporations, subject to the control and direction of the 
employer not only as to the work to be performed but also as 
to the manner and method of performance.

                D.      Stockholder Rights.

                        An option holder shall have none of the rights of a 
stockholder with respect to any shares covered by the option until such 
individual shall have exercised the option, paid the option price and 
been issued a stock certificate for the purchased shares.  No adjustment 
shall be made for dividends or distributions (whether paid in cash, 
securities or other property) for which the record date is prior to the 
date the stock certificate is issued.

                E.      Repurchase Rights.

                        The shares of Common Stock acquired upon the exercise 
of options granted under this Article Two may be subject to repurchase by 
the Corporation in accordance with the following provisions:

                        The Plan Administrator shall have the discretion to 
authorize the issuance of unvested shares of Common Stock under this 
Article Two.  Should the Optionee cease Service while holding such 
unvested shares, the Corporation shall have the right to repurchase any 
or all of those unvested shares at the option price paid per share.  The 
terms and conditions upon which such repurchase right shall be 
exercisable (including the period and procedure for exercise and the 
appropriate vesting schedule for the purchased shares) shall be 
established by the Plan Administrator and set forth in the instrument 
evidencing such repurchase right.

                        All of the Corporation's outstanding repurchase rights 
shall automatically terminate, and all shares subject to such terminated 
rights shall immediately vest in full, upon the occurrence of any 
Corporate Transaction under paragraph II of this Article Two, except to 
the extent:  (i) any such repurchase right is to be assigned to the 
successor corporation (or parent thereof) in connection with the 
Corporate Transaction or (ii) such termination is precluded by other 
limitations imposed by the Plan Administrator at the time the repurchase 
right is issued.

                        The Plan Administrator shall have the discretionary 
authority, exercisable either before or after the optionee's cessation of 
Service, to cancel the Corporation's outstanding repurchase rights with 
respect to one or more shares purchased or purchasable by the optionee 
under this Article Two and thereby accelerate the vesting of such shares 
in connection with the optionee's cessation of Service.

        II.     CORPORATE TRANSACTIONS

                A.      In the event of any of the following stockholder-
approved transactions (a "Corporate Transaction"):

                                (i)     a merger or acquisition in which the 
Corporation is not the surviving entity, except for a 
transaction the principal purpose of which is to change the 
State of the Corporation's incorporation,

                                (ii)    the sale, transfer or other 
disposition of all or substantially all of the assets of the 
Corporation, or

                                (iii)   any reverse merger in which the 
Corporation is the surviving entity,

                        then each option outstanding under this Article Two 
shall automatically become exercisable, during the five (5) business day 
period immediately prior to the specified effective date for the 
Corporate Transaction, with respect to the full number of shares of 
Common Stock purchasable under such option and may be exercised for all 
or any portion of such shares as fully vested shares of Common Stock.  An 
outstanding option under the Plan shall not be so accelerated, however, 
if and to the extent (i) such option is, in connection with the Corporate 
Transaction, either to be assumed by the successor corporation or parent 
thereof or be replaced with a comparable option to purchase shares of the 
capital stock of the successor corporation or parent thereof or (ii) the 
acceleration of such option is subject to other limitations imposed by 
the Plan Administrator at the time of grant.

                B.      Immediately following the consummation of the Corporate
Transaction, all outstanding options under the Plan shall, to the extent 
not previously exercised or assumed by the successor corporation or its 
parent company, terminate and cease to be exercisable.

                C.      Each outstanding option under this Article Two which
is assumed in connection with the Corporate Transaction or is otherwise to 
continue in effect shall be appropriately adjusted, immediately after 
such Corporate Transaction, to apply and pertain to the number and class 
of securities which would have been issuable, in consummation of such 
Corporate Transaction, to an actual holder of the same number of shares 
of Common Stock as are subject to such option immediately prior to such 
Corporate Transaction.  Appropriate adjustments shall also be made to the 
option price payable per share, provided the aggregate option price 
payable for such securities shall remain the same.  In addition, the 
class and number of securities available for issuance under the Plan 
following the consummation of the Corporate Transaction shall be 
appropriately adjusted.

                D.      Option grants under this Article Two shall in no way 
affect the right of the Corporation to adjust, reclassify, reorganize or 
otherwise change its capital or business structure or to merge, 
consolidate, dissolve, liquidate or sell or transfer all or any part of 
its business or assets.

        III.    CANCELLATION AND REGRANT

                The Plan Administrator shall have the authority to effect, at 
any time and from time to time, with consent of the affected option 
holders, the cancellation of any or all outstanding options under the 
Plan and to grant in substitution therefor new options covering the same 
or different numbers of shares of Common Stock but having an exercise 
price per share equal to one hundred percent (100%) of the fair market 
value of the Common Stock on the new grant date.

        IV.     EXTENSION OF EXERCISE PERIOD

                The Plan Administrator shall have full power and authority, 
exercisable from time to time in its sole discretion, to extend, either 
at the time the option is granted or at any time while such option 
remains outstanding, the period of time for which the option is to remain 
exercisable following the optionee's cessation of Service or death from 
the twelve (12)-month or shorter period set forth in the option agreement 
to such greater period of time as the Plan Administrator shall deem 
appropriate; provided, however, that in no event shall such option be 
exercisable after the specified expiration date of the option term.

        ARTICLE THREE



        MISCELLANEOUS

        I.      AMENDMENT OF THE PLAN

                The Board shall have complete and exclusive power and 
authority to amend or modify the Plan in any or all respects whatsoever. 
 However, no such amendment or modification shall, without the consent of 
the holders, adversely affect rights and obligations with respect to 
options at the time outstanding under the Plan.

        II.     EFFECTIVE DATE AND TERM OF PLAN

                The Plan shall become effective upon its adoption by the 
Board.  Unless sooner terminated in accordance with paragraph II of 
Article Two, the Plan shall terminate upon the earlier of (i) August 
____, 2007 or (ii) the date on which all shares available for issuance 
under the Plan shall have been issued or cancelled pursuant to the 
exercise or surrender of options granted hereunder.  If the date of 
termination is determined under clause (i) above, then options 
outstanding on such date shall not be affected by the termination of the 
Plan and shall continue to have force and effect in accordance with the 
provisions of the instruments evidencing such options.

        III.    USE OF PROCEEDS

                Any cash proceeds received by the Corporation from the sale 
of shares pursuant to options granted under the Plan shall be used for 
general corporate purposes.

        IV.     TAX WITHHOLDING

                The Corporation's obligation to deliver shares or cash upon 
the exercise or surrender of any option granted under the Plan shall be 
subject to the satisfaction of all applicable federal, state and local 
income and employment tax withholding requirements.

        V.      NO EMPLOYMENT/SERVICE RIGHTS 

                Neither the action of the Corporation in establishing or 
restating the Plan, nor any action taken by the Plan Administrator 
hereunder, nor any provision of the restated Plan shall be construed so 
as to grant any individual the right to remain in the employ or service 
of the Corporation (or any parent or subsidiary corporation) for any 
period of specific duration, and the Corporation (or any parent or 
subsidiary corporation retaining the services of such individual) may 
terminate such individual's employment or service at any time and for any 
reason, with or without cause.

        VI.     REGULATORY APPROVALS

                A.      The implementation of the Plan, the granting of any 
option hereunder, and the issuance of stock upon the exercise or 
surrender of any such option shall be subject to the Corporation's 
procurement of all approvals and permits required by regulatory 
authorities having jurisdiction over the Plan, the options granted under 
it and the stock issued pursuant to it.

                B.      No shares of Common Stock or other assets shall be 
issued or delivered under the Plan unless and until there shall have been 
compliance with all applicable requirements of Federal and state 
securities laws, including the filing and effectiveness of the Form S-8 
registration statement for the shares of Common Stock issuable under the 
Plan, and all applicable listing requirements of any stock exchange (or 
the Nasdaq National Market, if applicable) on which Common Stock is then 
listed for trading.