Dynamic magnetic information storage or retrieval – Automatic control of a recorder mechanism – Controlling the head
Patent
1996-07-09
1999-02-23
Hindi, Nabil
Dynamic magnetic information storage or retrieval
Automatic control of a recorder mechanism
Controlling the head
360 7705, 360 7804, G11B 5012
Patent
active
058750649
ABSTRACT:
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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Chainer Timothy
Schultz Mark Delorman
Webb Bucknell Chapman
Yarmchuk Edward John
Foerster Ingrid M.
Hindi Nabil
International Business Machines - Corporation
Lee Monica D.
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