Patent ID: 6266199
Filing Date: 2001-07-24
Classification: G11B

Abstract:
A method of monitoring a read signal amplitude and detecting physical damage in a magnetic disk drive comprising the steps of:reading data, written on a data track of a magnetic recording disk, with an MR element of a read head to provide a read signal;monitoring the amplitude of the read signal in response to the data written on the data track;comparing the monitored amplitude of the read signal with a first fixed amplitude level;continuing to read data written on the data track if the amplitude of the read signal is greater than or equal to the first fixed amplitude level;flagging a location on the data track if the amplitude of the read signal at the location on the data track is less than the first fixed amplitude level;rewriting the data at the flagged location on the data track using a write head;reading the rewritten data at the flagged location on the data track with the MR element of the read head;monitoring the amplitude of the read signal in response to the rewritten data at the flagged location on the data track;comparing the monitored amplitude of the read signal in response to the rewritten data with a second fixed amplitude level;continuing to read data written on the data track if the amplitude of the read signal is greater than or equal to the second fixed amplitude level;flagging a location on the data track with a damage flag if the amplitude of the read signal at the location on the data track is less than the second fixed amplitude level; andrewriting the data at the location having the damage flag at a new location on the magnetic recording disk.