Patent ID: 7522365

Claim:
A magnetic storage system, comprising: a disk having a surface provided with a plurality of tracks for storing data; a head for generating an analog signal when reading data from the disk; a read channel for providing digital data based on the analog signal generated by the head; and a main controller configured to: cause the head to read a data block of a selected track of the plurality of tracks at each of a plurality of fixed offsets from a center of the selected track; sample a gain in the read channel a plurality of times while the head is reading the data block at each of the plurality of fixed offsets to obtain a plurality of gain samples for each of the plurality of fixed offsets; determine whether the data block was written off-track based on at least one of the plurality of gain samples for at least one of the plurality of fixed offsets; and determine, in the event that the main controller determines that the data block was written off-track, whether an offset of the data block from the center of the selected track is constant based on at least one of the plurality of gain samples for at least one of the plurality of fixed offsets.