Inventors:
Robert L. Berry - Johnson City NY
Brandt C. Centerwall - Chenango Forks NY
Stephen G. Luning - San Jose CA
Forrest L. Wade - Tucson AZ
Assignee:
IBM Corporation - Armonk NY
International Classification:
G11B 712
Abstract:
A systematic method for detecting which head in a multiple head storage device contains errors and may be misaligned, and correcting for misalignment so that the data can be recovered. The apparatus includes a data buffer for storing a block of interleaved data read from the multiple head storage device, status bits, error detection circuitry for determining from the interleaved data, which if any of the heads is misaligned and for setting the status bits, data recovery control logic responsive to the status bits for sending control signals to the multiple head storage device for causing the misaligned head to move its position by small increments and to read data until the status bits indicate that the misaligned head has become aligned, and circuitry responsive to the status bits for writing data from the newly realigned head over the data which was read when that head was misaligned. The method includes steps of reading a block of interleaved data from a multiple head storage device and sending that data to a data buffer; detecting the existence of a misaligned head in determining which head is misaligned; generating error detection signals which indicate which head is misaligned; setting status bits in response to the error detection signals and sending control signals to the multiple head storage device to move the misaligned head by small increments and to read data from the misaligned head. The steps are repeated until the status bits indicate that the misaligned head has become realigned.