Samsung Electronics Co., Ltd.

Western Digital Technologies, Inc.

Tom S Chan

Derrick E Burton

Thao Hieu Banh

Yunxiang Wu

Chun Sei Tsai

Carl E Barlow

Colin W Morgan

Tung Thanh Nguyen

Bipinchandra V Gami

Yih Hurng Jung

Kwong-Tat Chan

Michael J Therrien

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 disk drive is disclosed comprising a disk having a plurality of tracks, wherein each track comprises a plurality of data sectors. A head is actuated radially over the disk for generating a read signal. A first read of a data sector is performed while adjusting an amplitude of the read signal in response to a gain control setting. When an error occurs while attempting to first read the data sector, a first jog value is generated in response to the gain control setting. The head is served over the data sector in response to the first jog value, and a second read of the data sector is performed.

Disk drive executing retry operation after adjusting jog value in response to gain control

A method for determining a flying height of a head of a hard disk drive. The disk drive includes a pre-amplifier and an automatic gain control ('AGC') circuit that are connected to the head. The method includes determining a first automatic gain control value based on AGC values at two delta pre-amplifier gain settings. A second automatic gain control value is determined based on AGC values at two different flying heights. A difference between the flying heights can be determined from the first and second automatic gain control values. If one of the flying heights is set to 0 the difference in gain values is equal to the flying height of the head.

Fly on demand in situ clearance measurement concept in hard disk drive

A method for writing servo information onto a disk of a hard disk drive with a servo writer. The method includes writing a plurality of spiral servo signals with a head. The spiral servo signals are used to write servo patterns using at least one timing window. The timing window is adjusted using a position error signal generated from the spiral servo signals. The adjusted timing window is then used to write servo patterns onto the disk. Adjusting the timing window compensates for irregularities in the spiral servo signals.

Window timing adjustment for spiral bursts

A method for providing data to determine an optimal track per inch ('TPI') density for a head of a hard disk drive. The method utilizes a VGA control signal that is used in an automatic gain control loop of the disk drive. First VGA values are stored during a routine where a head reads the disk at different offset positions across an N track. The head is then moved to an offset position of an adjacent track N+1 and then erases at least a portion of the N+1 track. Second VGA values are then stored as the head again reads the N track at different offset positions of the track. This process is repeated for a plurality of different TPI values. The effective head width is determined from the second VGA values are plotted relative to different TPI values. An optimum TPI value can be determined from this plot.

Growing community of inventors

San Marino, CA, United States of America

Tom S Chan