Seagate Technology Incorporated

Utt Heng Kan

Edmun Chian Song Seng

Kah Liang Gan

Det Hau Wu

Lin Nah Lim

Jose Mari Corral Toribio

Nan Ling Goh

Luh Chyuan Lau

Meng Suan June Lee

Xiong Liu

Timothy Richard Feldman

Wei Zhang

Qiang Bi

Jian Qiang

Kian Keong Ooi

Choon Kiat Lim

Edmun ChianSong Seng

Harry Tiotantra

Ban Hok Goh

AikChuan Lim

Peter S Harllee, Iii

Aik Chuan Lim

Wen Xiang Xie

James Lai Kein Chang

Kay Hee Tang

DetHau Wu

ChoonWei Ng

Chi Sern Tan

Winahyu Aji Bimas

Poh Seng Lim

Yam Pheng Tham

A method includes writing first data to a first track of a magnetic recording medium of a storage device. First parity sectors corresponding to the first data are written. The first parity sectors have a first size. Second parity sectors corresponding to the first data are written. The second parity sectors have a second size. Second data is written to a second track of the magnetic recording medium. The second track is adjacent to the first track. It is determined whether an unrecoverable data error has occurred on the second track. After writing to the second track and determining that no unrecoverable data error has occurred, the first and second parity sectors corresponding to the first data are released.

Mode hop mitigation solutions in a heat-assisted magnetic recording head

A method involves determining bit aspect ratios for interlaced tracks written to a magnetic recording medium. The interlaced tracks include top tracks that are written partially overlapping with bottom tracks. Isolated test tracks are written at first different bit aspect ratios to determine a top bit aspect ratio that achieves a first target areal density for the isolated test tracks. Test tracks are written at second different bit aspect ratios to determine a bottom bit aspect ratio that achieves a second target areal density for the test tracks. Top test tracks of the test tracks are written at the top bit aspect ratio. The top and bottom bit aspect ratios are selected to subsequently write partially-overlapping tracks on the magnetic recording medium.

Determining bit aspect ratios for partially-overlapping magnetic recording tracks

Apparatus and method for managing data transfers in a data storage device with rotational media that can be rotated at different speeds. In some embodiments, a non-volatile main memory is formed on a rotatable medium accessed by a moveable data transducer. A media cache provides a non-volatile data storage area. A control circuit directs writes to the main memory as the medium is rotated at a first speed and directs reads from the main memory as the medium is rotated at a higher, second speed. Writes during the rotation of the medium at the second speed are directed to the media cache instead of to the main memory so that no data are written to the main memory at the second speed. The media cache may also be located on the medium or may be formed from solid-state semiconductor memory.

Multi-speed data storage device with media cache for high speed writes

A method involves determining bit aspect ratios for interlaced tracks written to a magnetic recording medium. The interlaced tracks include top tracks that are written partially overlapping and interlaced with bottom tracks. Isolated test tracks are written at first different bit aspect ratios to determine a top bit aspect ratio that achieves a first target areal density for the isolated test tracks. Interlaced test tracks are written at second different bit aspect ratios to determine a bottom bit aspect ratio that achieves a second target areal density for the interlaced test tracks. Top test tracks of the interlaced test tracks are written at the top bit aspect ratio. The top and bottom bit aspect ratios are selected to subsequently write interlaced tracks on the magnetic recording medium.

Determining bit aspect ratios for interlaced magnetic recording tracks

Systems and methods are disclosed for performing band rewrites on shingled storage media based on error scan counts. In one embodiment, a device may comprise a data storage medium including a first band and a processor. The first band may include a plurality of tracks storing data in a shingled manner where a first track at least partially overlaps a second track. The processor may be configured to receive a write command directed to the first band, increment a first rewrite count of the first band based on the write command, and when the first rewrite count exceeds a first rewrite threshold, perform a read-modify-write (RMW) operation for all of the first band. In some embodiments, a device may maintain write counts for sections of a band, and perform RMW operations on less than all of the band.

Band rewrites based on error scan counts

A channel adjustment control adjusts a channel to reduce bit error rate in a disc drive. Variable gain register settings are read and compared to filter characteristics to provide an operational boost register setting for an adjustable gain amplifier in the channel. An operational pole register setting is provided based on the operational boost register setting and known parameters of the adjustable low pass filter. Low and high frequency data patterns are applied while the channel adjustment control reads the variable gain register settings.

Adjustment of pole frequency and boost settings of a filter in a channel

A method of and apparatus for generating a reader-to-writer offset for a head positioned over a track on a disc in a disc drive having a plurality of tracks is disclosed. A reader and a writer are mounted on the head in a non-overlapping manner with a gap between the reader and the writer, which is known as the reader-to-writer offset. A disc drive controller is operably connected to the reader and the writer. The disc drive controller determines the reader-to-writer offset of the head for each track by computing the difference between a first head position x1 and a second head position x2. The first head position x1 is an optimal head position for writing information on the track and the second head position x2 is a midpoint of an off-track capability (OTC) of the head. The OTC is a portion of a track pitch over which the reader is expected to read information that is free of an incorrigible bit error such that the writer-to-reader track misregistration (TMR) is minimized as the head is radially displaced the reader-to-writer offset to read information written on the track or to write information on the track.

Optimal reader-to-writer offset measurement of a head in a disc drive for reduced track misregistration

A method for compensating digital samples of an asymmetric read signal is presented. The method involves reading a digital sample of an asymmetric read signal V(t) ( ), generating a compensated sample at least when the digital sample requires compensation ( ), and outputting either the digital sample ( ) or the compensated sample ( ). Also presented is an asymmetry correction block ( ) of a read channel ( ) of a disc drive ( ) that includes an input ( ), a level detector ( ), a compensator ( ), and an output ( ). The level detector ( ) and the compensator ( ) receive the digital sample through the input ( ). The level detector ( ) determines whether the digital sample requires compensation. The compensator ( ) generates a compensated sample at least when the digital sample requires compensation. The output ( ) selectively outputs either the digital sample or the compensated sample.

Method and apparatus for correcting digital asymmetric read signals

A system for low acoustic noise spindle motor commutation is disclosed. The system contains a control device that generates commutation control signals which cause spindle motor drivers to source or sink current through windings of a spindle motor. The windings create electromagnetic fields which induce rotational movement in a spindle motor rotor. Low acoustic noise snubber devices are coupled to each winding and are dynamically configurable by the control device to provide low spindle motor driver charging current upon initial application of power to the spindle motor, and reduced acoustic noise and back EMF-generated current and voltage surges at the spindle motor driver during spindle motor commutation.

System and method for low acoustic noise spindle motor commutation

Growing community of inventors

Singapore, Singapore

Utt Heng Kan