Patent ID: 6943978

Claim:
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 high frequency signal in the spiral tracks to generate a position error signal used to maintain the head along a substantially circular target path; (b) using the head internal to the disk drive to read the sync marks in the spiral tracks to generate a spiral sync mark detect signal; (c) generating a coarse timing recovery measurement in response to the spiral sync mark detect signal; (d) generating a fine timing recovery measurement in response to the high frequency signal in the spiral tracks; (e) synchronizing a servo write clock in response to the coarse timing recovery measurement and the fine timing recovery measurement; 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.