US 8,619,383 B1Granted

Disk drive with dynamic head fly height back-off

AssigneeWestern Digital Technologies, Inc.

InventorsKameron K. Jung, Jame Show Leiong Hii

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Abstract

A disk drive is disclosed comprising a first disk surface comprising multiple zones, each comprising multiple tracks, a first head actuated radially over the first disk surface to write data to and read data from the first disk surface, and control circuitry coupled to the head. The control circuitry sets the first head to a first fly height over a first zone, writes a data pattern on a first track in the first zone, reads the data pattern to determine a first value of a first metric, writes a first frequency pattern on the first track, determines an initial amplitude of the first frequency pattern, writes a second frequency pattern over the first frequency pattern, determines a first value of a second metric for the first frequency pattern, and determines a first fly height value for the first zone by utilizing the first values of the first and second metrics.

Claims24

Dependent claims

A disk drive comprising:

a first disk surface comprising a plurality of zones, each zone comprising a plurality of tracks;
a first head actuated radially over the first disk surface to write data to the first disk surface and read data from the first disk surface;
and
control circuitry coupled to the first head, the control circuitry operable to:
(a) set the first head to a first fly height over a first zone of the first disk surface;
(b) write a data pattern on a first track in the first zone of the first disk surface;
(c) read the data pattern to determine a first value of a first metric;
(d) erase the data pattern after reading the data pattern;
(e) write a first frequency pattern on the first track in the first zone of the first disk surface;
(f) determine an initial amplitude of the first frequency pattern;
(g) write a second frequency pattern over the first frequency pattern;
(h) determine a first value of a second metric for the first frequency pattern;
and
(i) determine a first fly height value for the first zone of the first disk surface by utilizing the first value of the first metric and the first value of the second metric.

11 more elements

A method of operating a disk drive, the disk drive comprising a first disk surface, the first disk surface comprising a plurality of zones, each zone comprising a plurality of tracks, a first head actuated radially over the first disk surface to write data to the first disk surface and read data from the first disk surface, the method comprising:

(a) setting the first head to a first fly height over a first zone of the first disk surface;
(b) writing a data pattern on a first track in the first zone of the first disk surface;
(c) reading the data pattern to determine a first value of a first metric;
(d) erasing the data pattern after reading the data pattern
(e) writing a first frequency pattern on the first track in the first zone of the first disk surface;
(f) determining an initial amplitude of the first frequency pattern;
(g) writing a second frequency pattern over the first frequency pattern;
(h) determining a first value of a second metric for the first frequency pattern;
and
(i) determining a first fly height value for the first zone of the first disk surface by utilizing the first value of the first metric and first value of the second metric.

7 more elements

Dependencies are inferred from the claim text.