Patent ID: 7212364
Filing Date: 2007-05-01
Classification: G11B

Abstract:
1. A method of writing product servo sectors to a disk of a disk drive, the disk drive comprising control circuitry and a head disk assembly (HDA) comprising the disk, an actuator arm, a head connected to a distal end of the actuator arm, and a voice coil motor for rotating the actuator arm about a pivot to position the head radially over the disk, the disk comprising a plurality of spiral tracks, wherein each spiral track comprises a high frequency signal interrupted at a predetermined interval by a sync mark, the method comprising the steps of: (a) using the head internal to the disk drive to read the spiral tracks to generate a read signal; (b) processing the read signal to detect a sync mark in a spiral track and generating an associated sync mark reliability metric, the sync mark reliability metric representing a probability that the sync mark was detected accurately; (c) generating a timing recovery measurement in response to the detected sync mark and the sync mark reliability metric; (d) synchronizing a servo write clock in response to the timing recovery measurement; (e) processing the read signal representing the high frequency signal in the spiral track to generate a position error signal (PES) used to maintain the head along a substantially circular target path; and (f) using the servo write clock and the head internal to the disk drive to write the product servo sectors along the circular target path.