Disk drive expediting defect scan when quality metric exceeds a more stringent threshold
AssigneeWestern Digital Technologies, Inc.
InventorMing Jin
Life of this patent
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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.
Claims14
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.
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:
- 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.
Dependencies are inferred from the claim text.