Maxtor Corporation

Stmicroelectronics S.r.l.

Quantum Corporation

Bahjat Zafer

Kelly K Fitzpatrick

Peter A McEwen

John J McEwen, Legal Representative

Ara Patapoutian

Pauline Bolte

James Fitzpatrick

Ke Han

Kevin Dean Fisher

Angelo Dati

Pierandrea Savo

Steve Aronson

Steve Stupp

Jennifer Stander

Ezio Iacazio

Automatically optimizing and programming features of a disk drive read channel for a selected partial response (PR) target. This enables flexible PR targets to be used in the read channel. The flexible PR targets can have arbitrary coefficients, and the channel features (parameters, functions and algorithms) that are dependent on the flexible PR targets are automatically adapted and programmed in hardware or firmware. With flexible PR targets, the read channel can support longitudinal and perpendicular recording without compromising performance.

Flexible partial response targets for data detectors

A method for detecting signals affected by intersymbol interference provides for a path memory in the form of a trellis admitting survivor paths comprising a first and a second stage. The first stage includes a shift register exchange with a given number of states and a given length &#x3bb;. The first stage outputs a first state Son the survivor path for the best state A, and a second state Son the survivor path for another state B. The second stage is configured as a two-state shift register exchange having a respective memory length &#x39b;, including respective first and second registers. In the respective first and second registers the survivor paths are stored leading to a respective first &#x3c3;and second &#x3c3;state, whereby the respective first register contains the backend of the best survivor path, while the respective second register contains the backend of an alternative survivor path.

Trellis-based detection process and system

A media noise optimized (MNO) detector for a read channel compensates for pattern dependent media noise, and compensates for nonlinearities from many sources such as residual MR nonlinearity, residual nonlinear transition shift, partial erasure, write-induced nonlinearity, and steady-state mis-equalization. The MNO detector is implemented by adjusting a conventional Viterbi detector branch metric so that the channel output value (ideal value) can be a nonlinear function of the state/branch bits, and the branch metric scaling factor is a function of the state/branch. For a given state/branch, the ideal value is the mean of analog-to-digital converter samples for the pattern corresponding to the state/branch, and the branch metric scaling factor is proportional to the noise variance for the pattern corresponding to that state/branch.

Media noise optimized detector for magnetic recording

A methodology for designing an implementing high rate RLL codes is optimized for application to 10-bit ECC symbols, and provides rate 20/21, rate 50/51, rate 90/91 and other modulation code rates for use in magnetic recording channels. A relatively small subcode encoding&mdash;one easy to implement&mdash;is applied to a portion of the input stream, and the resulting base codeword is partitioned into nibbles that, in turn, are interleaved among the unencoded ECC symbols. Code constraints on the subcode word nibbles depend upon the values of adjacent unencoded symbols. The resulting codes provide excellent density and error propagation performance.

High rate runlength limited codes for 10-bit ECC symbols

A discrete-time filtering method for identifying defects in a magnetic medium, comprising the steps of: reading data signals from at least a portion of the medium; sampling the data signals to generate discrete time sample data; processing the sample data in a discrete time filter to detect deviation of the signal corresponding to media defects; and comparing the deviation of the signal to one or more threshold values to identify corresponding defect types on the recording medium. The filter can be configured to have an impulse response substantially matched to deviation of the signal corresponding to media defects.

Method and system for detection recording media defacts

A method and apparatus for encoding a sequence of 32 bit digital data words into a sequence of 33 bit code words in consonance with predetermined minimum zero run length (d) and predetermined maximum zero run length (k) for recording upon a magnetic medium within a magnetic recording channel is disclosed. The method comprises steps of dividing each data word into eight data nibbles, determining whether any data nibble contains all zeros. If no code violation, mapping the eight data nibbles to seven code nibbles and to four bits of a five bit code sub-word and setting a fifth control bit to one. If one or more code violations are present, embedding code violation locations within at least the five bit code sub-word and other code nibbles if necessary and remapping data nibbles ordinarily directed to the code sub-word and nibble locations to code locations otherwise containing the data nibbles determined to be code violations.

Rate 32/33 (D&equals;0, K&equals;6) run length limited modulation code having optimized error propagation

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Sunnyvale, CA, United States of America

Bahjat Zafer