Quantum Corporation

Stanley M Chang

Lisa Fredrickson

Clifford M Gold

Shih Mo

According to the invention, a data integrity code including logical block address ('LBA') and circuit implementation are provided. The code and implementing circuitry are utilized to enable data block LBA verification during a block transfer and retrieval process. The preferred data integrity code has embedded LBA information and also serves as a crosscheck code used to detect miscorrection by an error correction code ('ECC'). In a preferred disk drive embodiment, data integrity block ('DIB') is provided to verify that the LBA value associated with a given data block in a host interface matches the value associated with that same data block in a buffer memory and in a data sequencer. In a preferred method of use, data integrity/cross-check redundancy with LBA is appended to data blocks transmitted to a buffer memory and verified after the data block has been transferred from the buffer. After verification, the LBA is preferably written to the storage medium together with its associated data block to enable later LBA verification for blocks recovered from the storage medium. The LBA may also be verified when the data block is transferred back to a host from the buffer memory.

Data integrity and cross-check code with logical block address

A method and apparatus for reconstructing syndromes in a disk drive system. In the present invention, two levels of handling data errors are provided. The first attempt at correcting errors is performed by a dedicated error correction hardware. The error correction is based on a syndrome which was generated as a function of the data and ECC bits. An ECC code is selected such that the resulting syndromes produces a repeating, cyclical pattern. If the hardware correction circuit is unable to correct the error, the original syndrome value is reconstructed by processing the syndrome a number of times to where its current value in the next cycle corresponds to the original value in a previous cycle. This reconstructed syndrome is then used by the processor to handle the persisting error under firmware control.

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Irvine, CA, United States of America

Stanley M Chang