RECONSTRUCTION OF SYNDROMES FOR BI-LEVEL ON-THE-FLY ERROR CORRECTION IN DISK DRIVE SYSTEMS

摘要

A method and apparatus for reconstructing syndromes in a disk drive system. In thepresent invention, two levels (403, 406) of handling data errors are provided. A first attempt(403) at correcting errors is performed by a dedicated error correction hardware circuit (fig.6). The error correction is based on a syndrome which was generated as a function of thedata and ECC bits. An ECC code is selected such that the syndrome produces a cyclicallyrepeating pattern when processed in the correction hardware circuit. If the correction hardwarecircuit is unable to correct the error, the original syndrone value is reconstructed (405) byprocessing the syndrome a number of times until corresponds to the original value. Thereconstructed syndrome is then used (406) by a processor under firmware control to handlethe persisting errors.