Magnetic disk device and method for adjusting head flying height in magnetic disk device
AssigneesKabushiki Kaisha Toshiba, Toshiba Electronic Devices & Storage Corporation
InventorKazuhito Ichihara
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Abstract
According to an embodiment, the method for adjusting a head flying height in a magnetic disk device including a disk, a head that writes or reads data along tracks of the disk, and a heater provided near the head includes: determining a threshold of the head flying height; calculating a statistic from the chronological data of the head flying height; and adjusting the head flying height if the statistic exceeds the threshold.
Claims20
A method for adjusting a head flying height in a magnetic disk device including a disk, heads that write or read data to or from tracks of the disk, and a heater provided near each of the heads, the method comprising:
- determining a threshold of the head flying height;
- calculating a statistic from chronological data of the head flying height;
- and
- adjusting the head flying height if the statistic exceeds the threshold, wherein the statistic includes at least one kind of generalized mean of absolute value of deviations in the chronological data of the head flying height.
A method for adjusting a head flying height in a magnetic disk device including a disk, heads that write or read data to or from tracks of the disk, and a heater provided near each of the heads, the method comprising:
- determining a threshold of the head flying height;
- calculating a statistic from chronological data of the head flying height;
- and
- adjusting the head flying height if the statistic exceeds the threshold, wherein the threshold includes a flying upper limit value that is a value obtained by subtracting a margin of 0 nm or larger from an upper limit value of the head flying height at which the head is able to write or read data.
A magnetic disk device comprising:
- a disk;
- heads that write or read data to or from tracks of the disk;
- a heater provided near each of the heads;
- a head amplifier connected to the heads and the heater, exchanging signals with the heads and supplying power to the heater;
- and
- a controller connected to the head amplifier that measures a head flying height, determines a threshold of the head flying height, and calculates a statistic from chronological data of the head flying height,
- wherein the head amplifier adjusts the head flying height if the statistic exceeds the threshold, and wherein the threshold includes a flying upper limit value that is a value obtained by subtracting a margin of 0 nm or larger from an upper limit value of the head flying height at which the head is able to write or read data.
Dependencies are inferred from the claim text.