Seagate Technology Incorporated

Other

Edmun ChianSong Seng

UttHeng Kan

AikChuan Lim

Xiong Liu

Det Hau Wu

Lin Nah Lim

DetHau Wu

KianKeong Ooi

Qiang Bi

BengWee Quak

WingKong Chiang

Jimmy Pang

WeiMing Yeow

KayHee Tang

Stephen KowChiew Kuan

TaiVie Chiang

Ricardo SoonLian Lim

LinNah Lim

Edward Charles Gage

Tim Rausch

MingZhong Ding

Stanton MacDonough Keeler

ChoonKiat Lim

Minjie Ma

Utt Heng Kan

Bin Liu

Patrick TaiHeng Wong

Aik Chuan Lim

Kay Hee Tang

Curtis Michael Pleiss

Victor WengKhin Chew

Jeffrey Soon Beng Sim

NanLing Goh

Det Hua Wu

Patrick TaiHeng

MingZhong Dong

Ac Lim

HonYeong Mak

A cross-track profile of a known good test track on a recording medium is read during operation of a data storage device. Two or more center locations of the test track are determined at two or more different amplitude levels via a read transducer. A health condition of the read transducer is determined by comparing the two or more center locations of the test track with one another.

Health check for read/write head

A storage medium format is provided having a first band of a plurality of consecutive data storage tracks having user data stored thereto, a second band of a plurality of consecutive data storage tracks having other user data stored thereto, and a guard track medially disposed therebetween the first band and the second band and having system data stored thereto.

Data storage medium having system data stored in a guard band between zones of consecutive data storage tracks

A method to map defects is provided. A select data track of a storage medium is scanned for a defect. At least one data wedge affected by the defect on the select data track is identified. Each data wedge includes available area for writing user data defined between two servo wedges that include position information. The at least one affected data wedge is identified as unusuable.

Mapping defects on a data wedge basis

A method is provided. The method includes determining that a data sector included in a select data track is in error, the data sector in error includes at least one identified data wedge. The at least one defective data wedge in the data sector in error is located. The method also includes moving the at least one defective data wedge by utilizing at least one spare wedge on the select data track.

Defect reallocation for data tracks having large sector size

A multistage decoder circuit has an error reduction stage that includes an adaptation circuit. The adaptation circuit provides adaptable error reduction as a function of bit error rate. The multistage decoder circuit has an energization control circuit that couples to the adaptation circuit. The energization control circuit controls an energization of the adaptation circuit as a function of actual or expected channel quality.

Decoder with energization control circuit

A method of recovering data on a storage medium is provided. A first error correction scheme is performed on a high risk region of the storage medium. A second error correction scheme is performed on a remaining portion of the storage medium.

Maintaining data integrity in a data storage system

Apparatus and methods are disclosed that regulate head fly height so as to compensate for variation in height of a disk surface. An exemplary apparatus includes a circuit that detects disk height variation in response to variation in the gain of a variable gain amplifier, within an automatic gain control loop, that amplifies a read signal as the head reads from the disk surface. The circuit regulates the head fly height so as to compensate for the detected variation in disk height.

Fly height compensation using read gain control loop

A data recording apparatus includes a surface having a plurality of data tracks with leading track portions. A head moves along head paths over the data tracks to provide data access. The data access has a reduced reliability along a limited number of the leading track portions. Trailing path additions follow the head paths for the limited number of leading track portions. The trailing path additions providing overlapping data access for the limited number of leading track portions.

Overlapping data track access

A data storage medium and data storage system with improved efficiency of formatting are provided. One illustrative embodiment of the present invention pertains to a data storage medium. The data storage medium includes a first zone having servo information written with a first frequency, a second zone having servo information written with a second frequency, and a guard band disposed between the first zone and the second zone. The use of different frequencies in different zones contributes to optimizing the properties of the data storage medium, and the guard band contributes to optimizing the usage of the different zones.

Data storage medium with optimized servo format

A computer process establishes data frequencies for recording data in zones of a zone bit recording medium in a disc drive. At least three data points are identified for each zone correlating data frequencies and corresponding bit error rates, and a slope of a curve between each two data points is calculated. The slopes are averaged, and the data frequency is calculated based on the average slope. If a difference between the average and default slopes exceeds a first threshold value, or if a spread of the slopes exceeds a second threshold value, the data frequency is calculated based on the average slope and the default slope. In one embodiment, each of the three data points is generated by recording data in the zone at each of three selected data frequencies, reading the recorded data, and calculating bit error rates based on the recorded and read data.

Calculation of data frequencies in recording media

An enhanced interleave type error correction method is provided in which decoding of an enhanced interleave block is done. Subsequently the decoding may be done by decoding the estimated codewords multiple times using a single error correction code. In addition, a decoder and a digital communication system for implementing the enhanced interleave type error correction method are provided.

Enhanced interleave type error correction method and apparatus

Systems and methods are provided through which a time domain equalized signal-to-noise-ratio (ESNR) of an electronic device is determined by executing ESNR determining firmware in the electronic device. The ESNR is used to perform rejection/acceptance testing of the electronic device during manufacturing of the device, and/or to perform read channel tuning and optimization. In one embodiment, determination of the ESNR includes both phase level retry and global level retry.

System and method to determine the time domain equalized signal-to-noise ratio of a mass storage device

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

An apparatus and method of predicting functional capability of a data storage device having a plurality of information tracks, comprising performing a DC erase on three adjacent information tracks, writing a predetermined bit pattern on a middle track of the three adjacent information tracks, providing a first signal from the bit pattern to a variable gain amplifier to generate a first value of the variable gain amplifier, performing DC erases on the information tracks adjacent the middle track, reading the bit pattern from the middle track to provide a second signal to the variable gain amplifier to generate a second value of the variable gain amplifier, and operating on the first and second values of the variable gain amplifier to provide a track mis-registration value for use with a predetermined threshold value to determine the functional capability of the data storage device.

Track mis-registration measurement for a disc drive

A method and apparatus for obtaining optimum parameter values for a read channel employed in a disc drive storage system are provided in which data having a known pattern is written on a disc surface of the disc drive storage system. The data written on the disc surface is then read to obtain a readback signal. The readback signal is passed through the read channel. A readback signal response is obtained at an output test point of the read channel. The readback signal response at the output test point is compared with a target response of the read channel at the output test point. The comparison is carried out using frequency spectral analysis. At least one parameter of the read channel is adjusted if the readback signal response substantially differs from the target response.

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Singapore, Singapore

Edmun ChianSong Seng