Western Digital Technologies, Inc.

Thao Hieu Banh

Chun Sei Tsai

Derrick E Burton

Carl E Barlow

Dean V Dang

Tom S Chan

Tom Sai-Cheung Chan

Alexander Babinski

Colin W Morgan

Hien T Chu

Steven L Webb

Chirag C Patel

Ammar A Zayed

Wenli Zhu

Jaedeog Cho

Michael J Therrien

A data storage device is disclosed comprising a head actuated over a disk, wherein the head comprises a fly height actuator (FHA) configured to adjust a fly height of the head over the disk. A temperature of the data storage device is measured, and the FHA is controlled as a function of the measured temperature. A first quality metric of the data storage device is measured, and when the first quality metric falls below a threshold, the FHA control as a function of the measured temperature is disabled and the FHA is controlled to decrease the fly height of the head.

Data storage device controlling head fly height based on temperature

A data storage device is disclosed comprising a first head actuated over a first disk surface, and a second head actuated over a second disk surface. During a first revolution of the disk surfaces, a first set of servo sectors are written to the first disk surface and a second set of servo sectors are written to the second disk surface, wherein the first set of servo sectors are circumferentially offset from the second set of servo sectors. During a second revolution of the disk surfaces, at least one of the servo sectors in the first set is read from the first disk surface and at least one of the servo sectors in the second set is read from the second disk surface to control a position of the first head over the first disk surface.

Data storage device bank writing servo sectors for interleaved servo control processing

A data storage device is disclosed comprising a non-volatile memory (NVM). During a read operation, a sequence of signal samples is generated representing codewords stored in the NVM. The signal samples are buffered to generate buffered signal samples. The buffered signal samples are processed at a first frequency to detect a data sequence, and a bottleneck condition is detected associated with processing the buffered signal samples at the first frequency. When the bottleneck condition is detected, the buffered signal samples are processed at a second frequency higher than the first frequency to detect the data sequence.

Data storage device increasing sequence detector clock frequency when bottleneck condition is detected

A data storage device is disclosed comprising a disk comprising a plurality of data tracks each comprising a plurality of data sectors, and a head actuated over the disk. A first frequency preamble is written to a first data sector of a first data track and a second frequency preamble is written to a second data sector of a second data track, wherein the first frequency is different from the second frequency and the first data track is adjacent to the second data track.

Data storage device employing different frequency preambles in adjacent data tracks

A data storage device is disclosed comprising a head actuated over a disk. The head is positioned at a first radial location over the disk and at least part of a codeword on the disk is read to generate first signal samples. A first quality metric is generated for the first signal samples. The head is positioned at a second radial location over the disk different from the first radial location and at least part of the codeword is read to generate second signal samples. A second quality metric is generated for the second signal samples. A first subset of the first signal samples is combined with a second subset of the second signal samples based on the first and second quality metrics to generate a combined set of signal samples. An attempt is made to decode the codeword based on the combined set of signal samples.

Data storage device executing retry operation by buffering signal samples at different radial offsets

A data storage device is disclosed comprising a head actuated over a disk comprising a plurality of data tracks. Data is encoded into a first number of codewords, and the first number of codewords are interleave written to a first segment of a first data track. Data is encoded into a second number of codewords, and the second number of codewords are interleave written to a second segment of the first data track. The first number of codewords is different than the second number of codewords, and a size of the first segment is different than a size of the second segment.

Data storage device employing variable size interleave written track segments

A data storage device is disclosed comprising a head actuated over a disk comprising a plurality of tracks. A defect scan of at least one of the tracks is executed, and a log entry is generated when a defect is detected. After the defect scan, a verify operation is executed for at least two of the detected defects. A number of times the verify operation detects a false defect is counted, and whether the head is defective is determined based at least partly on the count.

Data storage device screening heads by verifying defects after defect scan

An apparatus includes: a media; a head over the media; a read channel, coupled to the head, configured to extract data from the media; control circuitry, coupled to the read channel, configured to execute a read command; and wherein the read channel is further configured to: generate, based on extracting the data from the media, a data condition indicator, and provide, for use by the control circuitry, the data and the data condition indicator.

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Lake Forest, CA, United States of America

Thao Hieu Banh