Method and system for accurate self-servowriting with normalization in a disk drive

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United States of America Patent

PATENT NO 6469859
SERIAL NO

09198730

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Abstract

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An accurate and time-efficient method and system for self-servowriting wherein at least one reference value used to position the transducer is updated for some, but not all, of the tracks to be written. The reference value(s) is dependent upon a predefined indicium of transducer position, such as the amplitude of the readback signal obtained from a written track when the transducer is positioned on the track. In a first embodiment, updating of the reference value(s) is performed at every Nth track written, where N is a fixed number or range of numbers determined by an expected track-to-track variation of the indicium. The servowriting system may be designed to dynamically increase or decrease N during servowriting in response to actual variations in the indicium. According to a second embodiment, updating is only performed when needed, e.g. when the variation of the measured indicium between two written tracks (not necessarily adjacent tracks) exceeds a predefined threshold value. For systems employing dual-element heads, servowriting accuracy is enhanced by performing a read head adjustment prior to updating of the reference values.

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Patent Owner(s)

  • HITACHI GLOBAL STORAGE TECHNOLOGIES NETHERLANDS B.V.

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Inventor(s)

Inventor Name Address # of filed Patents Total Citations
Chainer, Timothy Mahopac, NY 7 221
Schultz, Mark Delorman Elmsford, NY 47 713
Webb, Bucknell Chapman Ossinging, NY 25 407
Yarmchuk, Edward John Mahopac, NY 33 736

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