Patent ID: 6490691
Filing Date: 2002-12-03
Classification: G11B

Abstract:
A disk drive comprising:a recording medium; at least one head for reading information from said recording medium; a signal filter for filtering a selected set of frequencies from an output from the head when the signal filter is turned on; switching means for the signal filter which allows the signal filter to be turned off or on; an error detection means for detecting an error occurring in a first region when read by the head with the signal filter turned on; and an error processing means for executing a plurality of error recovery procedures when an error is detected by said error detection means, one of the error recovery procedures including thermal asperity detection by turning off the signal filter and using a signal from the head which has not been filtered by the signal filter to determine whether the error is caused by a thermal asperity, and if the error is caused by a thermal asperity, assigning an alternate region for first region.