FIRST AMENDMENT TO LEASE

This first amendment to lease  ("Amendment")  is made this 15th day of November,
1995 by and between  Great Oaks  Interests,  a  California  Limited  partnership
having an address at 10600 N. De Anza Blvd.,  Suite 200,  Cupertino,  California
95014  ("Landlord") and Komag  Incorporated,  a Delaware  corporation having its
principal place of business at 275 S. Hillview Drive Milpitas,  California 95035
("Tenant").

                                   WITNESSETH

WHEREAS  Landlord  and Tenant  entered  into a lease  dated  August 4, 1995 (the
"Lease") for the building at 1705  Automation  Parkway to be constructed on that
certain  13.54  acre site on the south  side of  Automation  Parkway in San Jose
("Premises"); and

WHEREAS effective the date of this Amendment, Landlord and Tenant wish to modify
the Lease to (i) limit  Landlord's  obligation to reimburse Tenant for the costs
of  constructing  the Building  Shell,  (ii) the change the timing of Landlord's
reimbursement  to Tenant  of such  costs,  (iii) to set  forth the final  square
footage of the Building, and (iv) to set forth the final Base Monthly Rent;

NOW, THEREFORE,  in order to effect the intent of the parties as set forth above
and for good and valuable consideration exchanged between the parties, the Lease
is amended as follows:

1. Landlord and Tenant have agreed that  Landlord's  obligation to pay the costs
associated  with the  construction  of the  Building  Shell  shall be limited as
provided  herein.  Total  Project Costs (as defined in Exhibit "B" of the Lease)
shall  be  fixed  at  the  sum  of   Fourteen   Million   and   No/100   Dollars
($14,000,000.00).  This amount has been determined with reference to Exhibit "B"
of the Lease as follows:

  Project Cost Item                          Amount

  (i)    Land cost                         $5,036,913 (13.54 acres, $8.54 psf)
  (v)    Interest                            $537,518 (1 year - 9.75%)
  (vi)   Loan fees                           $231,000 (1.75% of $13,200,000)
  (vii)  Real estate taxes:                  $123,331 (1 year - land only)
  (ix)   Lease commission:                   $597,849 ($3.00 psf)
         Total                             $6,526,611
  Total to be paid to Tenant               $7,473,389
  for items (ii), (iii), (viii) & (x)

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Landlord  shall pay the loan  fees,  real  estate  taxes  and  lease  commission
directly  to the party owed as such  amounts  become  due.  In lieu of  Landlord
making  progress  payments to Tenant  during the  construction  of the  Building
Shell,  Landlord  shall pay Tenant on the  Commencement  Date,  the sum of Seven
Million Four Hundred Seventy Three Thousand Three Hundred Eighty Nine and No/100
Dollars  ($7,473,389)  to reimburse  Tenant for  Landlord's  agreed share of the
balance of the costs to construct the Building  Shell.  Tenant agrees to pay, at
Tenant's expense,  any additional costs necessary to complete the Building Shell
in substantial conformance with the building shell plans attached as Exhibit "C"
to the Lease.

2. Base  Monthly  Rent has been  determined  based on the formula  contained  in
Exhibit  "B," the Total  Project  Costs of  $14,000,000  and the best  available
financing rate of 8% interest, 20 year amortization to be the sum of One Hundred
Forty Thousand Five Hundred Twenty One and 93/100 Dollars ($140,521.93).

3. Final  square  footage of the Building is agreed by Landlord and Tenant to be
199,293 square feet.

4. All  defined  terms shall have the same  meanings as in the Lease,  except as
otherwise stated in this Amendment.

5.  Except as hereby  amended,  the Lease and all of the  terms,  covenants  and
conditions  thereof shall remain unmodified and in full force and effect. In the
event of any conflict or inconsistency  between the terms and provisions of this
Amendment and the terms and provisions of the Lease, the terms and provisions of
this Amendment shall prevail.

IN WITNESS WHEREOF, the parties hereto have set their hands to this Amendment as
of the day and date first above written.

Landlord                                  Tenant
Great Oaks Interests,                     Komag Incorporated,
a California limited partnership          a Delaware corporation


By:  ___________________________          By: _____________________________
Its:  General Partner                     Its: VP & CFO


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