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                                                                   EXHIBIT 10.15


           SECOND AMENDMENT TO CREDIT AGREEMENT - THREE YEAR FACILITY



         This Second Amendment to Credit Agreement - Three Year Facility is
entered into as of this fifteenth day of December, 1995, by and among (a)
KOMAG, INCORPORATED, a Delaware corporation ("Borrower"); (b) the banks from
time to time party hereto, together with their respective successors and
assigns (each a "Bank" and collectively "Banks"); and FIRST INTERSTATE BANK OF
CALIFORNIA, a California banking corporation ("FICAL"), as agent for the Banks
(in such capacity, the "Agent").

     This Second Amendment amends that certain Credit Agreement - Three Year
Facility dated as of December 15, 1994 and that certain First Amendment thereto
dated March 29, 1995 (jointly, the "Agreement"), each of which were executed by
and among Borrower, Banks and the Agent as follows:

              1.    SECTION 1.01., DEFINED TERMS., "Maturity Date", page 5:
delete this definition and replace with

              "December 15, 1999, unless an extension shall occur under Section
              2.01, in which case "Maturity Date" shall mean the amended
              Maturity Date resulting from such extension.";

              2.    SECTION 2.01., THE REVOLVING LOANS., (c) Commitment Fee.,
page 9: delete this section and replace with

              "Borrower agrees to pay to the Agent, for the pro rata benefit of
              the Banks in accordance with their respective Commitment
              Percentages, a commitment fee equal to ten (10) basis points of
              the Aggregate Commitment, calculated on the basis of a 360-day
              year for the actual days elapsed, payable on December 15, 1995 and
              on each anniversary date thereafter.";

              3.    SECTION 2.01., THE REVOLVING LOANS., (f) Non-Utilization
Fee., page 10: delete this section and replace with

              "Borrower agrees to pay to the Agent, for the pro rata benefit of
              the Banks in accordance with their respective Commitment
              Percentages, a non-utilization fee equal to fifteen (15) basis
              points of average daily unused portion of the Aggregate Commitment
              from December 15, 1995 until the Maturity Date, and any extensions
              thereof, payable on the last day of each December, March, June and
              September (for the preceding quarter) commencing on the first such
              date occurring after December 15,1995 and on the Maturity Date.",
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              4.    SECTION 2.01., THE REVOLVING LOANS., (g) Extension of
Maturity Date., pages 10 and 11, inclusive: delete "the then current Maturity
Date" and replace with "each anniversary date" on lines 5, lines 7 and 8 and
lines 9 and 10;

              5.    SECTION 2.03., INTEREST RATE AND PAYMENT DATES., (c)
Eurodollar Rate Loans., page 13: delete the schedule and replace with

              "If Borrower's Consolidated Debt to Consolidated Capital is less
              than .25 to 1.0: 75 basis points; and

              If Borrower's Consolidated Debt to Consolidated Capital is equal
              to or greater than .25 to 1.0: 90 basis points.";

              6.    SECTION 2.03., INTEREST RATE AND PAYMENT DATES., (c)
Eurodollar Rate Loans., page 13: add a new introductory sentence to the last
paragraph as follows

              "Notwithstanding anything to the contrary contained in the
              Agreement, for purposes of calculating the rates referred to in
              this subsection, Borrower's convertible subordinated debt shall
              not be included as part of its Consolidated Debt.";

              7.    SECTION 6.01., AFFIRMATIVE COVENANTS., (b) Notices and
Information.,(i), (c), page 24: delete "$1,000,000" wherever it appears and
replace with "$10,000,000";

              8.    SECTION 6.02., NEGATIVE COVENANTS., (d) Consolidated
Tangible Net Worth., line 7, page 27: insert the following between
"Subsidiaries" and "adjusted"

                    "(other than equity investments by the Borrower in its
                    Consolidated Subsidiaries or equity investments by the
                    Borrower's Consolidated Subsidiaries in the Borrower)";

              9.    SECTION 6.02., NEGATIVE COVENANTS., (e) Domestic
Unrestricted Cash Balances., page 27: delete this section and its header in
their entirety;

              10.   SECTION 6.02., NEGATIVE COVENANTS., (f) Liens, Etc., (g)
Debt., (h) Dividends, Etc., (i) Consolidation, Merger or Acquisition., A) Loans,
Investments, Secondary Liabilities., and (k) Asset Sales., pages 27 through 30,
inclusive: reletter as

                    (e) Liens, Etc., (f) Debt., (g) Dividends, Etc., (h)
                    Consolidation, Merger or Acquisition., (i) Loans,
                    Investments, Secondary Liabilities. , and A) Asset Sales.


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              11.   SECTION 6.02., NEGATIVE COVENANTS., (f) Debt., (iv), page
28: delete "$35,000,000" wherever it appears and replace with "$100,000,000" and
delete "$20,000,000" and replace with "$50,000,000";

              12.   SECTION 6.02., NEGATIVE COVENANTS., (g) Dividends., page 28,
lines 10 through 13, inclusive: delete "repurchase up to 500,000 shares of stock
per fiscal year of Borrower on the open market to meet employee stock option
plan requirements for Dastek employees; and (iv) make repurchases of employee
stock and/or employee stock options which in the aggregate do not exceed
$500,000 per fiscal year" and replace with

                    "repurchase stock of Borrower in an amount not to exceed
                    $15,000,000 in any calendar year";

              13.   SECTION 6.02., NEGATIVE COVENANTS., (j) Asset Sales., (i),
page 30: delete "12.5%" and replace with "20%";

              14.   SECTION 6.02., NEGATIVE COVENANTS., (I) Domestic Assets of
Borrower and its Consolidated Subsidiaries., page 30: delete this section and
its header in their entirety;

              15.   SECTION 6.02., NEGATIVE COVENANTS., page 30: add a new "(k)"
as follows

              "(k)" Debt Service Coverage Ratio. Permit earnings before interest
              plus taxes plus depreciation plus amortization ("EBITDA") divided
              by interest expense plus scheduled principal payments plus
              $15,000,000 to be less than 2.0 to 1.0 at any time during the term
              of the Agreement. This ratio will be calculated on a rolling prior
              four quarter basis.";

              16.   SECTION 7.01., EVENTS OF DEFAULT.(h), page 32: delete this
subsection in its entirety;

              17.   SECTION 7.01., EVENTS OF DEFAULT., subsections (i) and (j),
pages 32 and 33, inclusive: reletter as "(h)" and "(i)", respectively;

              18.   SECTION 7.01., EVENTS OF DEFAULT., subsection (i), lines 2
through 4, inclusive, page 33: delete "or against any guarantor (at such time or
times as there are any outstandings under the Borrowings which were the subject
of any guarantee executed by such guarantor),";

              19.   SECTION 9.02., NOTICES, ETC., line 9, page 37: delete "or
VII";

              20.   SECTION 9.07., EFFECTIVENESS; BINDING EFFECT; GOVERNING
LAW., line 8, page 39: delete "$35,000,000" and replace with "$95,000,000";
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              21.   Signature page, page 41: change the Borrower's zip code from
"95124" to "95035",

              22.   Signature page, page 41: change Standard Chartered Bank's
address from "707 Wilshire Boulevard, Los Angeles, California 90017, Attention:
Rita Raychaudhuri" to "7 World Trade Center, New York, New York 10048,
Attention: Peter Dodds";

              23.   Delete Exhibit A and replace with the attached;

              24.   Delete Exhibit 1 and replace with the attached;

              25.   Delete Exhibit 4 and replace with the attached; and

              26.   Borrower shall pay to the Agent a sum not to exceed $5,000
simultaneously with its execution of this Second Amendment to reimburse the
Agent for its attorney's fees in conjunction with the preparation and
negotiation of this Second Amendment.

              27.   Borrower hereby represents and warrants to the Banks and the
Agent that (a) the representations and warranties contained in the Agreement are
true in all material respects on and as of the date of this Second Amendment,
(b) no event has occurred and is continuing which constitutes an Event of
Default or Potential Event of Default, and (c) the documents previously
delivered to the Agent and the Banks pursuant to clauses (ii), (iii) and (v) of
Section 4.01 (a) remain in full force and effect.

              28.   Except as specifically amended pursuant to the foregoing
paragraphs of this Second Amendment, all recitals, representations, warranties,
covenants, undertakings, promises, indemnities, terms, conditions and provisions
of the Agreement shall remain in full force and effect and shall be and remain
unaffected by this Second Amendment.

              29.   This Second Amendment shall become effective when the Agent
(which shall promptly distribute such information to each of the Banks) shall
have received all of the following:

              (a)   Counterparts of this Second Amendment signed by the
Borrower, the Banks and the Agent.

              (b)   The Revolving Notes in the form attached hereto as Exhibit A
duly signed by an authorized officer of the Borrower in favor of each of the
Banks. Such promissory notes shall constitute the Revolving Notes as defined in
and for the purpose of the Agreement and shall be deemed to have amended and
restated the Revolving Notes previously executed and delivered by the Borrower
under the Agreement.
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              30.   This Amendment may be signed in any number of counterparts,
each of which shall be an original, with the same effect as if the signatures
thereto and hereto were upon the same instrument. This Second Amendment and the
Agreement constitute the entire agreement and understanding among the parties
hereto and supersedes any and all prior agreements and understandings, oral or
written, relating to the subject matter hereof.

              31.   This Amendment shall be governed by, and construed and
enforced in accordance with, the internal laws of the State of California
without regard to principles of conflicts of laws.

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

              IN WITNESS WHEREOF, the parties hereto have duly executed this
Second Amendment as of the day and year first hereinabove written.


FIRST INTERSTATE BANK OF CALIFORNIA,        KOMAG, INCORPORATED,
as the Agent                                as Borrower
and as a Bank

By:                                         By:
    --------------------------------           ---------------------------------


Title:                                      Title:
      ------------------------------              ------------------------------

                                            Address:
                                            275 South Hillview Drive
                                            Milpitas, CA 95035

                                            Attention:   David H .Allen
                                                         Treasurer

Address:
South Bay Regional Corporate
177 Park Center Plaza
San Jose, CA 95113

Attention:   Erik B. Larsen
             Vice President


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COMERICA BANK - CALIFORNIA                  ABN-AMRO BANK, N.V.
as a Bank                                   as a Bank
                                            By:  ABN AMRO North America,
                                                   Inc. , as agent

By:                                         By:
    ------------------------------             ---------------------------------

Its:                                        Its:
    ------------------------------              --------------------------------

Address:                                    Address:
333 West Santa Clara Street                 101 California Street, Suite 4550
San Jose, CA 95113                          San Francisco, CA 94111-5812

Attention:   Lori S. Edwards                Attention:   Robin S. Yim
             First Vice President                        Vice President


STANDARD CHARTERED BANK
as a Bank

By:
   -------------------------------

Its:
    ------------------------------
Address:
7 World Trade Center
New York, NY 10048

Attention:   Peter Dodds
             Vice President


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