-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
 MFgwCgYEVQgBAQICAf8DSgAwRwJAW2sNKK9AVtBzYZmr6aGjlWyK3XmZv3dTINen
 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 LEsv+U0JFnqRzzTHF0ISfKMH+FORf2nyktp6VG+YvsDrCo40yMeJvGYZWVhwuNkL
 CRVCE/tWxC5Svz5xi4/GOA==

<SEC-DOCUMENT>0001179110-03-008619.txt : 20031009
<SEC-HEADER>0001179110-03-008619.hdr.sgml : 20031009
<ACCEPTANCE-DATETIME>20031009132841
ACCESSION NUMBER:		0001179110-03-008619
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20031007
FILED AS OF DATE:		20031009

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			JDS CAPITAL LP
		CENTRAL INDEX KEY:			0001264533
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-16852
		FILM NUMBER:		03934716

	BUSINESS ADDRESS:	
		STREET 1:		780 THIRD AVENUE
		STREET 2:		45TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10017
		BUSINESS PHONE:		2128339921

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			J&G LLC
		CENTRAL INDEX KEY:			0001264540
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-16852
		FILM NUMBER:		03934715

	BUSINESS ADDRESS:	
		STREET 1:		780 THIRD AVENUE
		STREET 2:		45TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10017
		BUSINESS PHONE:		2128339921

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			JDS CAPITAL MANAGEMENT LLP
		CENTRAL INDEX KEY:			0001264541
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-16852
		FILM NUMBER:		03934717

	BUSINESS ADDRESS:	
		STREET 1:		780 THIRD AVENUE
		STREET 2:		45TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10017
		BUSINESS PHONE:		2128339921

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			SAMBERG JOSEPH D
		CENTRAL INDEX KEY:			0001264542
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-16852
		FILM NUMBER:		03934713

	BUSINESS ADDRESS:	
		STREET 1:		780 THIRD AVENUE
		STREET 2:		45TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10017
		BUSINESS PHONE:		2128339921

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			KOMAG INC /DE/
		CENTRAL INDEX KEY:			0000813347
		STANDARD INDUSTRIAL CLASSIFICATION:	MAGNETIC & OPTICAL RECORDING MEDIA [3695]
		IRS NUMBER:				942914864
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0102

	BUSINESS ADDRESS:	
		STREET 1:		1710 AUTOMATION PWY
		CITY:			SAN JOSE
		STATE:			CA
		ZIP:			95131
		BUSINESS PHONE:		4085762000

	MAIL ADDRESS:	
		STREET 1:		1710 AUTOMATION PWY
		CITY:			SAN JOSE
		STATE:			CA
		ZIP:			95131
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>FORM 4 -
<TEXT>
<XML>
<ownershipDocument>
    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>
<periodOfReport>2003-10-07</periodOfReport>
<notSubjectToSection16>0</notSubjectToSection16>
    <issuer>
        <issuerCik>0000813347</issuerCik>
        <issuerName>KOMAG INC /DE/</issuerName>
        <issuerTradingSymbol>KOMG</issuerTradingSymbol>
</issuer>
<reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001264533</rptOwnerCik>
            <rptOwnerName>JDS CAPITAL LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>780 THIRD AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>45TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10017</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>0</isDirector>
<isOfficer>0</isOfficer>
<isTenPercentOwner>1</isTenPercentOwner>
<isOther>0</isOther>
<officerTitle></officerTitle>
<otherText></otherText>
</reportingOwnerRelationship>
</reportingOwner>
<reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001264540</rptOwnerCik>
            <rptOwnerName>J&amp;G LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>780 THIRD AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>45TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10017</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>0</isDirector>
<isOfficer>0</isOfficer>
<isTenPercentOwner>1</isTenPercentOwner>
<isOther>0</isOther>
<officerTitle></officerTitle>
<otherText></otherText>
</reportingOwnerRelationship>
</reportingOwner>
<reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001264541</rptOwnerCik>
            <rptOwnerName>JDS CAPITAL MANAGEMENT LLP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>780 THIRD AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>45TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10017</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>0</isDirector>
<isOfficer>0</isOfficer>
<isTenPercentOwner>1</isTenPercentOwner>
<isOther>0</isOther>
<officerTitle></officerTitle>
<otherText></otherText>
</reportingOwnerRelationship>
</reportingOwner>
<reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001264542</rptOwnerCik>
            <rptOwnerName>SAMBERG JOSEPH D</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>780 THIRD AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>45TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10017</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>0</isDirector>
<isOfficer>0</isOfficer>
<isTenPercentOwner>1</isTenPercentOwner>
<isOther>0</isOther>
<officerTitle></officerTitle>
<otherText></otherText>
</reportingOwnerRelationship>
</reportingOwner>
<nonDerivativeTable><nonDerivativeTransaction><securityTitle><value>Common Stock</value>
</securityTitle>
<transactionDate><value>2003-10-07</value>
</transactionDate>
<transactionCoding><transactionFormType>4</transactionFormType>
<transactionCode>S</transactionCode>
<equitySwapInvolved>0</equitySwapInvolved>
</transactionCoding>
<transactionAmounts><transactionShares><value>6000</value>
</transactionShares>
<transactionPricePerShare><value>19.35</value>
</transactionPricePerShare>
<transactionAcquiredDisposedCode><value>A</value>
</transactionAcquiredDisposedCode>
</transactionAmounts>
<postTransactionAmounts><sharesOwnedFollowingTransaction><value>2869946</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature><directOrIndirectOwnership><value>I</value>
</directOrIndirectOwnership>
<natureOfOwnership><value>See footnote.</value>
<footnoteId id="F1"></footnoteId>
</natureOfOwnership>
</ownershipNature>
</nonDerivativeTransaction>
<nonDerivativeTransaction><securityTitle><value>Common Stock</value>
</securityTitle>
<transactionDate><value>2003-10-07</value>
</transactionDate>
<transactionCoding><transactionFormType>4</transactionFormType>
<transactionCode>S</transactionCode>
<equitySwapInvolved>0</equitySwapInvolved>
</transactionCoding>
<transactionAmounts><transactionShares><value>38200</value>
</transactionShares>
<transactionPricePerShare><value>19.188</value>
</transactionPricePerShare>
<transactionAcquiredDisposedCode><value>A</value>
</transactionAcquiredDisposedCode>
</transactionAmounts>
<postTransactionAmounts><sharesOwnedFollowingTransaction><value>2831746</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature><directOrIndirectOwnership><value>I</value>
</directOrIndirectOwnership>
<natureOfOwnership><value>See footnote.</value>
<footnoteId id="F1"></footnoteId>
</natureOfOwnership>
</ownershipNature>
</nonDerivativeTransaction>
<nonDerivativeTransaction><securityTitle><value>Common Stock</value>
</securityTitle>
<transactionDate><value>2003-10-08</value>
</transactionDate>
<transactionCoding><transactionFormType>4</transactionFormType>
<transactionCode>S</transactionCode>
<equitySwapInvolved>0</equitySwapInvolved>
</transactionCoding>
<transactionAmounts><transactionShares><value>81120</value>
</transactionShares>
<transactionPricePerShare><value>19.3536</value>
</transactionPricePerShare>
<transactionAcquiredDisposedCode><value>A</value>
</transactionAcquiredDisposedCode>
</transactionAmounts>
<postTransactionAmounts><sharesOwnedFollowingTransaction><value>2750626</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature><directOrIndirectOwnership><value>I</value>
</directOrIndirectOwnership>
<natureOfOwnership><value>See footnote.</value>
<footnoteId id="F1"></footnoteId>
</natureOfOwnership>
</ownershipNature>
</nonDerivativeTransaction>
</nonDerivativeTable>
<derivativeTable></derivativeTable>
<footnotes><footnote id="F1">These securities are being filed as part of a group consisting of JDS Capital, L.P., J&amp;G, LLC, JDS Capital Management, LLC and Joseph D. Samberg. These securities are owned directly by JDS Capital, L.P., J&amp;G, LLC and Joseph D. Samberg. These securities may be deemed to be owned indirectly by JDS Capital Management, LLC, as the general partner of JDS Capital, L.P., and by Joseph D. Samberg, as the managing member of each of JDS Capital Management, LLC and J&amp;G, LLC. As of the date hereof, of the 2,750,626 shares of Common Stock owned directly and indirectly by this group, JDS Capital, L.P. directly owns 2,078,258 shares of Common Stock, J&amp;G, LLC directly owns 101,010 shares of Common Stock and Joseph D. Samberg directly owns 571,358 shares of Common Stock. The 125,320 shares of Common Stock disposed of were owned directly by JDS Capital, L.P.</footnote>
</footnotes>
<ownerSignature><signatureName>/s/ Joseph D. Samberg, managing member of JDS Capital Management, LLC, general partner of JDS Capital, L.P. </signatureName>
<signatureDate>2003-10-09</signatureDate>
</ownerSignature>
<ownerSignature><signatureName>/s/ Joseph D Samberg, managing member of J&amp;G, LLC</signatureName>
<signatureDate>2003-10-09</signatureDate>
</ownerSignature>
<ownerSignature><signatureName>/s/ Joseph D. Samberg, managing member of JDS Capital Management, LLC</signatureName>
<signatureDate>2003-10-09</signatureDate>
</ownerSignature>
<ownerSignature><signatureName>/s/ Joseph D. Samberg</signatureName>
<signatureDate>2003-10-09</signatureDate>
</ownerSignature>
</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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