Disk drive calibrating a laser write power for heat assisted magnetic recording
AssigneeWestern Digital Technologies, Inc.
InventorMichael Alex
Life of this patent
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Abstract
A disk drive is disclosed comprising a head actuated over a disk, wherein the head comprises a laser for heating the disk while writing data to the disk. The disk drive receives write commands, and increases a power of the laser to a write power for heating the disk while writing data to the disk. A calibration interval is adjusted based on the power applied to the laser over time, and the write power is calibrated at the calibration interval.
Claims20
A disk drive comprising:
- a disk;
- a head actuated over the disk, wherein the head comprises a laser for heating the disk while writing data to the disk;
- and
- control circuitry operable to:
- receive write commands;
- increase a power of the laser to a write power for heating the disk while writing data to the disk;
- measure a duration that the power is applied to the laser;
- adjust a calibration interval based on the duration;
- and
- calibrate the write power at the calibration interval.
A disk drive comprising:
- a disk;
- a head actuated over the disk, wherein the head comprises a laser for heating the disk while writing data to the disk;
- and
- control circuitry operable to:
- calibrate a first write power for the laser;
- execute a plurality of write operations using the first write power;
- after executing the plurality of write operations, recalibrate the write power for the laser by:
- increasing the write power to higher than the first write power and measuring a quality metric;
- and
- when the quality metric indicates degrading performance at the higher write power, decreasing the write power to lower than the first write power;
- and
- when the quality metric indicates degrading performance at the lower write power, reset the write power to the first write power, and calibrate at least one other component of the disk drive.
A method of operating a disk drive, the disk drive comprising a head actuated over a disk, wherein the head comprises a laser for heating the disk while writing data to the disk, the method comprising:
- receiving write commands;
- increasing a power of the laser to a write power for heating the disk while writing data to the disk;
- measuring a duration that the power is applied to the laser;
- adjusting a calibration interval based on the duration;
- and
- calibrating the write power at the calibration interval.
A method of operating a disk drive, the disk drive comprising a head actuated over a disk, wherein the head comprises a laser for heating the disk while writing data to the disk, the method comprising:
- calibrating a first write power for the laser;
- executing a plurality of write operations using the first write power;
- after executing the plurality of write operations, recalibrating the write power for the laser by:
- increasing the write power to higher than the first write power and measuring a quality metric;
- and
- when the quality metric indicates degrading performance at the higher write power, decreasing the write power to lower than the first write power;
- and
- when the quality metric indicates degrading performance at the lower write power, resetting the write power to the first write power, and calibrating at least one other component of the disk drive.
Dependencies are inferred from the claim text.