Disk drive employing fly height calibration tracks to account for magnetic entropy and thermal decay
First Claim
1. A disk drive comprising:
- a disk comprising a plurality of tracks including a first fly height calibration track and a second fly height calibration track;
a head actuated over the disk;
a fly height actuator operable to control a fly height of the head in response to a fly height control signal; and
control circuitry operable to;
when a refresh event is detected, write calibration data to the second fly height calibration track;
after writing calibration data to the second fly height calibration track, read the first fly height calibration track in order to calibrate the fly height control signal applied to the fly height actuator; and
after calibrating the fly height control signal, read the second fly height calibration track in order to recalibrate the fly height control signal applied to the fly height actuator.
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Accused Products
Abstract
A disk drive is disclosed comprising a head actuated over a disk comprising a plurality of tracks including a first fly height calibration track and a second fly height calibration track. The disk drive further comprises a fly height actuator operable to control a fly height of the head in response to a fly height control signal. When a refresh event is detected, calibration data is written to the second fly height calibration track. After writing calibration data to the second fly height calibration track, the first fly height calibration track is read in order to calibrate the fly height control signal applied to the fly height actuator. After calibrating the fly height control signal, the second fly height calibration track is read in order to recalibrate the fly height control signal applied to the fly height actuator.
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Citations
20 Claims
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1. A disk drive comprising:
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a disk comprising a plurality of tracks including a first fly height calibration track and a second fly height calibration track; a head actuated over the disk; a fly height actuator operable to control a fly height of the head in response to a fly height control signal; and control circuitry operable to; when a refresh event is detected, write calibration data to the second fly height calibration track; after writing calibration data to the second fly height calibration track, read the first fly height calibration track in order to calibrate the fly height control signal applied to the fly height actuator; and after calibrating the fly height control signal, read the second fly height calibration track in order to recalibrate the fly height control signal applied to the fly height actuator. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of operating a disk drive comprising a head actuated over a disk comprising a plurality of tracks including a first fly height calibration track and a second fly height calibration track, and a fly height actuator operable to control a fly height of the head in response to a fly height control signal, the method comprising:
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when a refresh event is detected, writing calibration data to the second fly height calibration track; after writing calibration data to the second fly height calibration track, reading the first fly height calibration track in order to calibrate the fly height control signal applied to the fly height actuator; and after calibrating the fly height control signal, reading the second fly height calibration track in order to recalibrate the fly height control signal applied to the fly height actuator. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification