Western Digital Corporation

Quantum Corporation

Trinh C Bui

Carl Bonke

Joanne Wu

Stanley Chang

Phong Tran

Patrick J Lee

Marc E Acosta

Clifford M Gold

William R Akin, Jr

Bryan John Mee

Hoa V Luong

Hang Diem Nguyen

Minnie Uppuluri

George Li

Steve Paul

A method of coordinating access to a data buffer including a plurality of data blocks, using a buffer list with a plurality of entries corresponding to the data blocks. Each buffer list entry includes: (i) a status code for indicating the status of data in the corresponding data block, and (ii) a partial address common to both the next buffer list entry and a data block corresponding to said next buffer list entry. A status code is selected from a cyclical set of sequential status codes having a period of N, the status codes sequentially, and alternately, representing the most recent history of a data block, including: (i) full status, indicating data in the data block has been retrieved from the storage device or is to be stored to the storage device, or (ii) empty status, indicating data transferred out of the data block to a host or to the storage device. A store flag maintains a status code representing empty status, and a retrieve flag maintains a status code representing full status. When storing data into the data buffer, locating a desired buffer list entry list with an empty status code by traversing the buffer list, calculating the address of each entry using the partial address in the previous entry, until the desired entry is found. The address of the data block corresponding to the found entry is calculated and data is stored in the data block when the status code of the entry matches the store flag status code. The found entry status code is advanced once, and if the entry is last in the buffer list the store flag status code is advanced twice. Similarly, when retrieving data from the data buffer, locating a desired entry in the buffer list with a full status code by traversing the buffer list, calculating the address of each entry using the partial address in the previous entry, until the desired entry is found. The address of the data block corresponding to the found entry is calculated and data is retrieved from the data block when the status code of the entry matches the retrieve flag status code. The found entry status code is advanced once, and if the entry is last in the buffer list the retrieve flag status code is advanced twice.

Buffer management and system coordination method

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

Apparatus and method for detecting occurrence of a non-pulse interval of predetermined length between a beginning pulse and an ending pulse as included within a sequence comprising a unique timing mark within a stream of pulses supplied from a source with a state machine. The method of the state machine includes the the steps of:

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Trinh C Bui