Disk drive for detecting a polarity error of a magnetoresistive head by detecting a sync mark
AssigneeWestern Digital Technologies, Inc.
InventorsGrant S. Christiansen, Mark D. Hagen
Life of this patent
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Abstract
A disk drive is disclosed comprising a bias layer in a magnetoresistive (MR) head actuated over a disk having a plurality of data tracks, each data track comprising a plurality of sectors. A sync mark detector detects a sync mark pattern in a sector, wherein when the sync mark pattern is detected a sync mark detect signal and a polarity signal are generated. The polarity signal indicates when the polarity of the bias layer has deviated from a preferred polarity, wherein the polarity of the bias layer is realigned back toward the preferred polarity.
Claims6
A disk drive comprising:
- (a) a disk comprising a plurality of data tracks, each data track comprising a plurality of sectors, each sector comprising:
- a preamble field for storing a predetermined periodic data sequence;
- a sync field for storing a predetermined sync mark pattern;
- and
- a data field for storing data;
- (b) a magnetoresistive (MR) head comprising a MR read element having a bias layer magnetizable toward a preferred polarity, the MR head actuated radially over the disk for generating a read signal;
- (c) a sync mark detector, responsive to the read signal, for detecting the sync mark pattern, wherein when the sync mark pattern is detected the sync detector generates a sync mark detect signal and a polarity signal, the polarity signal indicative of a polarity of the bias layer;
- and
- (d) a means for modifying the polarity of the bias layer when the polarity signal indicates the polarity of the bias layer has deviated from the preferred polarity.
A method of compensating for a polarity error of a bias layer in a magnetoresistive (MR) head deployed in a disk drive, the bias layer magnetizable toward a preferred polarity, the disk drive comprising a disk having a plurality of data tracks, each data track comprising a plurality of sectors, each sector comprising a preamble field for storing a predetermined periodic data sequence, a sync field for storing a predetermined sync mark pattern, and a data field for storing data, the method comprising the steps of:
- (a) detecting the sync mark pattern in a read signal generated by the MR head;
- (b) when the sync mark pattern is detected, generating a sync mark detect signal and a polarity signal, the polarity signal indicative of a polarity of the bias layer;
- and
- (c) modifying the polarity of the bias layer when the polarity signal indicates the polarity of the bias layer has deviated from the preferred polarity.
Dependencies are inferred from the claim text.