Disk drive expediting defect scan when quality metric exceeds a more stringent threshold
First Claim
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1. A disk drive comprising:
- a disk comprising a plurality of data tracks;
a head actuated over the disk; and
control circuitry operable to;
read data from one of the data tracks to generate a read signal;
generate a quality metric in response to the read signal;
when the quality metric exceeds a first threshold, detect a defect in at least part of the data track; and
when the quality metric exceeds a second threshold different than the first threshold;
reread the data track to regenerate the quality metric; and
when the quality metric exceeds the second threshold at least twice, detect the defect.
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Abstract
A disk drive is disclosed comprising a head actuated over a disk comprising a plurality of data tracks. Data is read from one of the data tracks to generate a read signal, and a quality metric is generated in response to the read signal. When the quality metric exceeds a first threshold, a defect is detected in at least part of the data track. When the quality metric exceeds a second threshold different than the first threshold, the data track is reread to regenerate the quality metric, and when the quality metric exceeds the second threshold at least twice, the defect is detected.
239 Citations
14 Claims
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1. A disk drive comprising:
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a disk comprising a plurality of data tracks; a head actuated over the disk; and control circuitry operable to; read data from one of the data tracks to generate a read signal; generate a quality metric in response to the read signal; when the quality metric exceeds a first threshold, detect a defect in at least part of the data track; and when the quality metric exceeds a second threshold different than the first threshold; reread the data track to regenerate the quality metric; and when the quality metric exceeds the second threshold at least twice, detect the defect. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method of operating a disk drive, the disk drive comprising a head actuated over a disk comprising a plurality of data tracks, the method comprising:
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reading data from one of the data tracks to generate a read signal; generating a quality metric in response to the read signal; when the quality metric exceeds a first threshold, detecting a defect in at least part of the data track; and when the quality metric exceeds a second threshold different than the first threshold; rereading the data track to regenerate the quality metric; and when the quality metric exceeds the second threshold at least twice, detecting the defect. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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Specification