Method and apparatus for error detection
AssigneeSeagate Technology LLC
InventorsClifton James Williamson, Peter Igorevich Vasiliev
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Abstract
The present invention is an error detection and correction scheme that enables the use of Horner's algorithm for the computation of EDC syndromes from the computed error pattern. Specifically, “transformed” EDC syndromes are computed during the read back of data and parity from the medium. The transformed syndromes are values of the polynomial whose coefficients occur in reverse order from that of the EDC codeword polynomial. In essence, by reversing the order of the coefficients, the Chien search processes the terms in descending order which is the right direction for Horner evaluation.
Claims30
A method of detecting errors in transferred data comprising steps of:
- receiving the transferred data having an error detection code appended to user data;
- calculating a transformed error detection code syndrome;
- calculating a recomputed error detection code syndrome;
- comparing the recomputed transformed error detection code syndrome to the transformed error detection code syndrome;
- and
- if the recomputed transformed error detection code syndrome corresponds to the transformed error detection code syndrome, transferring the data to a host.
A decoder comprising;
- a transformed error detection code (EDC) syndrome generator receiving transferred data and producing a transformed error detection code syndrome;
- a recomputed transformed error detection syndrome generator operable to generate a transformed error detection code syndrome associated with a computed correction pattern in the transferred data;
- and
- a comparator coupled to the transformed EDC syndrome generator and the recomputed transformed error detection syndrome generator operable to compare the transformed error detection code syndrome to the recomputed transformed errordetection code syndrome.
A data storage device comprising:
- an error correction module in the device operable to correct errors in retrieved data retrieved from a data storage medium;
- and
- means for determining whether the retrieved data has been miscorrected without recomputing an error detection code syndrome from the corrected data.
A method of detecting an error in error correction code (ECC) encoded data comprising steps of:
- receiving ECC encoded data;
- transforming the data in a transformed error detection code (EDC) syndrome generator into a transformed error detection code syndrome;
- receiving the ECC encoded data in a recomputed transformed error detection syndrome generator;
- generating a recomputed transformed error detection syndrome associated with a computed correction pattern in the ECC encoded data;
- and
- comparing the transformed EDC syndrome with the recomputed transformed error detection syndrome.
A data communication system comprising:a data carrying medium;
- a data transfer mechanism operably connected to the data carrying medium receiving data from the medium and sending data to the medium;
- and
- an error correction module connected to the mechanism operable to correct errors in data received from the medium;
- and
- means for determining whether received data has been miscorrected without recomputing an error detection code (EDC) syndrome from the corrected data.
Dependencies are inferred from the claim text.