Patent ID: 8611037
Filing Date: 2013-12-17
Classification: G11B

Abstract:
1. A magnetic disk drive comprising: a magnetic disk comprising a plurality of substantially concentric tracks and which is rotated by a spindle motor, each of the plurality of tracks comprising a plurality of servo frames with servo burst data and repeatable runout correction data written thereto, wherein the repeatable runout correction data is used to correct an repeatable error in the servo burst data synchronizing with rotation of the magnetic disk, comprises a pattern repeated at a predetermined period, and is written so that beginning of write is delayed by a time corresponding to a correction amount with respect to a base point corresponding to a synchronization timing position in the servo frame; a detector configured to detect a phase delay amount corresponding to a time elapsed until the repeated pattern is read from the servo frame by a magnetic head, with respect to the synchronization timing position; a converter configured to convert the detected phase delay amount into a correction amount corresponding to the phase delay amount; and a correction module configured to correct, based on the correction amount resulting from the conversion, a demodulated value of servo burst data read from the servo frame by the magnetic head.