Western Digital Corporation

Texas Instruments Corporation

Joanne Wu

Carl Bonke

Trinh C Bui

Stanley Chang

Phong Tran

Patrick J Lee

Marc E Acosta

Kang Xiao

Dong Cho

Stephen Finch

Patrick Conley

Mark J Blair

James Schaffner

The present invention provides a method and apparatus for providing position detection using a unique binary sequence encoded in indexing bits stored in servo wedges. The present invention generates a unique binary sequence (UBS) code and stores the bits of such a code in the indexing bits of the servo wedges. The bits are read from the servo wedges and used to provide unique identification of head position. Each servo wedge and each data field can be uniquely identified, even servo wedges and data fields under different heads. The present invention may be used to provide initial position detection, position verification during normal operation, and position verification upon head switching. When used for position verification, the present invention uses a confidence block to determine the confidence level with which the head is believed to be correctly positioned. One or more programmable thresholds may be used to qualify operations such as reading information from a disk, writing information to a disk, or seeking a location on a disk. If these thresholds are not met for the corresponding operations, the initial position detection capability of the present invention may be used to provide position recovery.

Position detection scheme for headerless disk controller

A disk drive having error detection and correction capability includes a dedicated finite field processor for performing corrections and for generating software syndromes for miscorrection detection. The processor operates over a finite field under program control and performs parallel finite field multiplication and addition operations in a single execution cycle.

Disk drive with embedded finite field processor for error correction

An intelligent disk drive employing a controller which performs high speed error correction and miscorrection detection using a finite field processor. The error correction code is defined over a finite field and the error detection code is defined over an extension field of the finite field. The finite field processor performs calculation over both the finite field and extension field to provide high speed error correction and correction validation.

Disk drive with fast error correction validation

An intelligent disk drive having error detection and correction capability employs an embedded error correction controller with a pipelined architecture for performing error correction under program control. The pipelined architecture provides parallel operand fetching and instruction execution for high speed operations during error correction.

Disk drive with pipelined embedded ECC/EDC controller which provides

An intelligent disk drive includes a controller which embeds user data address information into error correction code check symbols written to the data storage disk. The address information is not written to disk, but address errors are detected by decoding the error correction code check symbols during read operations. Disk space is saved while maintaining robust address error detection.

Disk drive with error code embedded sector identification

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Joanne Wu