Method and apparatus for detecting and remediating in response to insufficient or excessive HAMR optical power
First Claim
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1. A method comprising:
- determining high and low power levels applied via a laser used to record data to a heat-assisted recording medium using the laser, the high power level resulting in interference with an adjacent track and the low power level resulting in reduced reliability of the data recorded to the track;
determining, via a power sensor, an optical power level applied via the laser when recording a track to the heat-assisted recording medium; and
in response to the optical power level being at or below the low power level or at or above the high power level, taking remedial action to prevent loss of data on one or more of the track and the adjacent track, wherein the remedial action comprises one of;
adjusting a first counter of adjacent track writes associated with the adjacent track, the adjacent track being rewritten when the first counter exceeds a first threshold; and
adjusting a second counter of adjacent track writes associated with the track, the track being rewritten when the second counter exceeds a second threshold.
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Abstract
An optical power level applied via a laser when recording data to a track of a heat-assisted recording medium is determined. In response to the optical power level being too low or too high, remedial action is taken to prevent loss of data on one or more of the track and an adjacent track.
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Citations
19 Claims
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1. A method comprising:
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determining high and low power levels applied via a laser used to record data to a heat-assisted recording medium using the laser, the high power level resulting in interference with an adjacent track and the low power level resulting in reduced reliability of the data recorded to the track; determining, via a power sensor, an optical power level applied via the laser when recording a track to the heat-assisted recording medium; and in response to the optical power level being at or below the low power level or at or above the high power level, taking remedial action to prevent loss of data on one or more of the track and the adjacent track, wherein the remedial action comprises one of; adjusting a first counter of adjacent track writes associated with the adjacent track, the adjacent track being rewritten when the first counter exceeds a first threshold; and adjusting a second counter of adjacent track writes associated with the track, the track being rewritten when the second counter exceeds a second threshold. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An apparatus comprising:
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circuitry configured to read a signal from a power sensor that detects an optical power level applied via a laser when recording data to a track of a heat-assisted recording medium; and a controller coupled to the circuitry and configured to; determine a high power level that when applied to the laser during recording, results in interference with an adjacent track; determine a low power level that, when applied to the laser during recording, results in reduced reliability of the data; determine, via the power sensor, that the optical power when recording data to the track is at or below the low power level or at or above the high power level; and in response to the optical power level being at or below the low power level or at or above the high power level, take remedial action to prevent loss of data on one of the track or an adjacent track, wherein the remedial action comprises one of; adjusting a first counter of adjacent track writes associated with the adjacent track, the adjacent track being rewritten when the first counter exceeds a first threshold; and adjusting a second counter of adjacent track writes associated with the track, the track being rewritten when the second counter exceeds a second threshold. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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16. A method comprising:
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determine, via a power sensor optically coupled to a laser of a read/write head, that an optical power level has exceeded a first threshold by a power level delta when recording a target track to a heat-assisted recording medium; determining that side peaks of a dibit response of the target track have exceeded a second threshold, indicating the target track is written off-center and a direction thereof; determining a combined metric comprising the power level delta and the side peaks of the dibit response; and in response to the combined metric exceeding a remedial response threshold, rewrite one or more adjacent tracks adjacent to the target track to prevent loss of data on the one or more adjacent tracks due to adjacent track interference. - View Dependent Claims (17, 18, 19)
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Specification