Patent ID: 9286159
Filing Date: 2016-03-15
CPC Classification: G06F,G11B,H03M

Claim Text:
1. A data storage device that stores data in tracks that include a plurality of sectors of data, the data storage device comprising: a first-level error correction system that writes track parity information on each track in a selected band of tracks, the track parity information being calculated using a first mathematical algorithm using data stored on one track and performs error correction using the track parity information on a selected track when the selected track is read; and wherein the first-level error correction system detects unreadable sectors in the selected track and wherein the first-level error correction includes generating modified track parity data using readable sectors and skipping unreadable sectors; and a second-level error correction system that writes track band parity information for the selected band of tracks, the track band parity information being calculated using a second mathematical algorithm using data stored on the selected band of tracks and performs error correction using the track band parity information on a selected track band when the selected track band is read; and wherein the second-level error correction system performs error correction after the first-level error correction has completed and the second-level error correction includes generating modified track band parity data using readable and corrected sectors supplied by the first-level error correction system.