Disk drive with information encoded in the position error signal fields

A data storage device comprising:

• a disk with a plurality of position error signals (PES) recorded thereon, the PES including at least first and second PES groups with the second PES group being radially offset from the first PES group;
• means for rotating the disk;
• a read head which is positionable over the disk when rotating so that a PES induces a waveform in the read head when the read head passes a PES;
• a PES data detector which receives the waveform from the read head and outputs a plurality of data bits corresponding to the waveform;
• at least first and second pattern registers for storing the plurality of data bits corresponding to a waveform;
• timing controller for selecting the first pattern register to receive the plurality of data bits for each PES in a first PES group and for selecting the second pattern register for each PES in a second PES group, the PES in first group passing the read head a time which is not equal to a time that the PES in the second PES group passes the read head;
• and
• a PES data processor for extracting track location information from the plurality of data bits in first or second registers, the PES data processor including a syndrome calculator and an error corrector.

A data storage device comprising:

• a disk with a plurality of position error signals (PES) recorded thereon, the PES including at least first and second PES groups with the second PES group being offset from the first PES group;
• a read head which is positionable over the disk when rotating so that a PES induces a waveform in the read head when the read head passes over a PES;
• a PES data detector which receives the waveform from the read head and outputs a plurality of data bits corresponding to the waveform based on the magnetic transitions in the waveform;
• and
• a PES data processor for extracting track location information from the plurality of data bits comprising:
• a bit-vector extractor for partitioning the plurality of data bits into a plurality of bit-vectors;
• a mapper which outputs a corresponding symbol in a predetermined table, for each bit-vector in the table, and for each bit-vector not in the table, outputs a selected symbol, the symbols having fewer bits than the bit-vector;
• a syndrome calculator which uses the symbols from the mapper to compute error correction syndromes;
• and
• an error register which records PES data processing errors.