Browse Prior Art Database

Packwriter Write Correction System

IP.com Disclosure Number: IPCOM000074432D
Original Publication Date: 1971-Apr-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 2 page(s) / 24K

Publishing Venue

IBM

Related People

Palmer, RS: AUTHOR [+2]

Abstract

The resultant signal detected by read head 11 above read track 12 (illustrated by dashed lines) midway between adjacent servo tracks 13 and 14 on a magnetic disk comprises signal components reflecting the polarity and duration of the servo signals written on tracks 13 and 14 by servo-write heads 15 and 16, respectively. If the disk contains a material irregularity 18 or defect near a magnetic transition between oppositely polarized portions of one of the servo tracks 13 and 14, then the corresponding read-track signal 12 will be diminished at that point. Accordingly, this angular position is detected and the angular position of the weak signal is stored in a memory, not shown. The servo track causing the weak signal is then rewritten with a servo signal modified at that angular position.

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Packwriter Write Correction System

The resultant signal detected by read head 11 above read track 12 (illustrated by dashed lines) midway between adjacent servo tracks 13 and 14 on a magnetic disk comprises signal components reflecting the polarity and duration of the servo signals written on tracks 13 and 14 by servo-write heads 15 and 16, respectively. If the disk contains a material irregularity 18 or defect near a magnetic transition between oppositely polarized portions of one of the servo tracks 13 and 14, then the corresponding read-track signal 12 will be diminished at that point. Accordingly, this angular position is detected and the angular position of the weak signal is stored in a memory, not shown. The servo track causing the weak signal is then rewritten with a servo signal modified at that angular position. To modify the servo signal, the length in the direction of motion of the recorded servo track is increased in the proximity of the transition, thereby producing a corresponding increase in the amplitude of the read-track signal and whereby a constant amplitude read signal is achieved. Accordingly, to decrease the amplitude the length is decreased.

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