AMENDED AND RESTATED CERTIFICATE OF INCORPORATION 
                                  OF KOMAG, INCORPORATED,
                                  A Delaware Corporation


The undersigned, Stephen C. Johnson and William L. Potts, Jr.,
hereby certify that:

     FIRST:  They are the duly elected and acting President and Secretary,
             respectively, of said corporation.
     SECOND: The Certificate of Incorporation of said corporation was 
             originally filed with the Secretary of State of Delaware on
             October 29, 1986 under the name Komag Delaware, Inc.
     THIRD:  The Certificate of Incorporation of said corporation shall
             be amended and restated to read in full as follows:

                             ARTICLE I       
     The name of the corporation (herein called the "Corporation") is 
KOMAG, INCORPORATED.

                             ARTICLE II      
     The address of the registered office of the Corporation in the 
State of Delaware is Corporation Trust Center, 1209 Orange Street, in 
the City of Wilmington, County of New Castle, zip code 19801.  The name 
of the registered agent of the Corporation at such address is The 
Corporation Trust Company.

                             ARTICLE III     

     The purpose of the Corporation is to engage in any lawful act or 
activity for which corporations may be organized under the General 
Corporation Law of the State of Delaware.

                             ARTICLE IV      

     The Corporation shall be authorized to issue One Hundred Fifty-One 
Million (151,000,000) shares of capital stock having an aggregate par 
value of One Million Five Hundred Ten Thousand Dollars ($1,510,000).  
This Capital Stock shall be divided into two classes, Common Stock and 
Preferred Stock, both classes having a par value.  The authorized Common 
Stock shall be One Hundred Fifty Million shares (150,000,000) shares 
having a par value of one cent ($.01) per share for an aggregate class 
par value of One Million Five Hundred Thousand Dollars ($1,500,000).  
The authorized Preferred Stock shall be One Million (1,000,000) shares 
having a par value of one cent ($.01) per share for an aggregate class 
par value of Ten Thousand Dollars ($10,000).  The Board of Directors of 
the corporation is hereby empowered (i) to determine the preferences, 
privileges, or restrictions of such Preferred Stock, including (but not 
limited to) the dividend rights and rate, conversion and voting rights, 
redemption rights and the terms and prices thereof (including any 
provision for a sinking fund), or liquidation preferences thereof, if 
any, (ii) to divide the Preferred Stock into different series consisting 
of any number of shares, each series having different rights, 
provisions, or conditions from any other series and (iii) to increase or 
decrease the number of shares of any series so designated, but not below 
the number of shares of any such series then outstanding.  The 
Corporation is also authorized to issue debentures (convertible into the 
Common Stock or Preferred Stock or non-convertible, either with or 
without voting rights) and/or warrants or options to purchase Common 
stock or Preferred Stock.

                             ARTICLE V      

     In the furtherance and not in limitation of the powers conferred 
by statute, the Board of Directors is expressly authorized to make, 
alter, amend or repeal the By-Laws of the Corporation.

                             ARTICLE VI      

     The number of directors of the Corporation shall be fixed from 
time to time by a by-law or amendment thereof duly adopted by the Board 
of Directors or by the Stockholders.

                             ARTICLE VII      

     All rights to vote and all voting power shall be vested in the 
Common Stock, and any Preferred Stock with voting rights pursuant to the 
terms thereof, and any such holders thereof shall be entitled at all 
elections of directors to as many votes as shall equal the number of 
votes which (except for this provision as to cumulative voting) he would 
be entitled to cast for the election of directors with respect to his 
shares of stock multiplied by the number of directors to be elected, and 
such holder may cast all of such votes for a single director or may 
distribute them among the number to be voted for, or for any two or more 
of them as he may see fit, and to vote for each share upon all other 
matters.

                             ARTICLE VIII      

     Elections of directors need not be by written ballot unless the 
By-laws of the Corporation shall be provided.

                             ARTICLE XI

     Meetings of stockholders may be held within or without the State 
of Delaware, as the By-laws may provide.  The books of the Corporation 
may be kept (subject to any provision contained in the statutes) outside 
the State of Delaware at such place or places as may be designated from 
time to time by the Board of Directors or in the By-laws of the 
Corporation.

                             ARTICLE X

     A director of the Corporation shall not be personally liable to 
the Corporation or its stockholders for monetary damages for breach of 
fiduciary duty as a director, except for liability (i) for any breach of 
the director's duty of loyalty to the Corporation or its stockholders, 
(ii) for acts or omissions not in good faith or which involve 
intentional misconduct or knowing violation of law, (iii) under Section 
174 of the Delaware General Corporation Law, or (iv) for any transaction 
from which the director derived any improper personal benefit.

                             ARTICLE XI

     The Corporation reserves the right to amend, alter, change or 
repeal any provision contained in this restated Certificate of 
Incorporation, in the manner now or hereafter prescribed by statute, and 
all rights conferred upon stockholders herein are granted subject to 
this reservation.

                             ARTICLE XII

     The Corporation reserves the right to amend, alter, change or 
repeal any provision contained in this Amended and Restated Certificate 
of Incorporation, in the manner now or hereafter prescribed by statue, 
and all rights conferred upon stockholders herein are granted subject to 
this reservation.

                             ARTICLE XIII

     The Corporation shall have perpetual existence.


    FOURTH: The foregoing Amended and Restated Certificate of  Incorporation
            has been duly adopted by the Corporation's Board of Directors 
            and stockholders in accordance with the applicable provisions 
            of Sections 242 and 245 of the General Corporation Law of the 
            State of Delaware.

    IN WITNESS WHEREOF, the undersigned have executed this certificate 
   on July 22, 1998.

KOMAG, INCORPORATED


By:     
Stephen C. Johnson, 
President
Attest:         
William L. Potts, Jr., Secretary