Patent ID: 7339761
Filing Date: 2008-03-04
Classification: G11B

Abstract:
1. A method for wedge time shift calibration in a disk drive, the disk drive comprising a disk, a head actuated over the disk, and a spindle motor for rotating the disk at an operating speed in response to a spindle control current generated by a spindle control system, the disk having a plurality of spaced-apart embedded servo wedges that define a plurality of concentric data tracks, the method comprising the steps of: (a) seeking across the disk and measuring wedge-to-wedge times between servo wedges; (b) calculating a wedge-to-wedge time shift value using the wedge-to-wedge times; (c) determining whether the wedge-to-wedge time shift time value exceeds a predetermined threshold; (d) if the wedge-to-wedge time shift value exceeds the predetermined threshold, then identifying a wedge time shift zone; and (e) storing information for compensating for the identified wedge time shift zone during disk operations.