Patent ID: 7136244

Claim:
A disk drive comprising: (a) a disk comprising a plurality of tracks, each track comprising a plurality of data sectors; (b) a head actuated radially over the disk, the head for generating a read signal while reading data from at least one of the data sectors; (c) a sampling device for sampling the read signal to generate read signal sample values; (d) a sequence detector for detecting an estimated data sequence from the read signal sample values; (e) a buffer; (f) a disk controller for processing a read command received from a host computer by: positioning the head over a selected data sector to generate a first read signal; sampling the first read signal to generate a first sequence of read signal sample values; detecting a first estimated data sequence using the sequence detector from the first sequence of read signal sample values; storing in the buffer the first estimated data sequence; if a read error occurs: repositioning the head over the selected data sector to generate a second read signal; sampling the second read signal to generate a second sequence of read signal sample values; detecting a second estimated data sequence using the sequence detector from the second sequence of read signal sample values; averaging the second estimated data sequence with the first estimated data sequence stored in the buffer to generate an averaged estimated data sequence; storing the averaged estimated data sequence in the buffer; and processing the averaged estimated data sequence stored in the buffer to recover the selected data sector.