Patent ID: 7016134

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 method comprising the steps of: (a) inserting a head positioning pin of an external spiral servo writer into the HDA, the head positioning pin for engaging the actuator arm; (b) using the external spiral servo writer to derive a radial location of the head; (c) actuating the head positioning pin in response to the radial location of the head in a closed loop system to rotate the actuator arm about the pivot in order to position the head radially over the disk while writing a plurality of spiral tracks, each spiral track comprising a high frequency signal interrupted at a predetermined interval by a sync mark; (d) removing the head positioning pin from the HDA; (e) using the head internal to the disk drive to read the spiral tracks to generate a read signal; (f) processing the read signal to detect the sync marks in the spiral tracks to synchronize a servo write clock; (g) processing the read signal to demodulate the high frequency signal in the spiral tracks to generate a position error signal used to maintain the head internal to the disk drive along a substantially circular target path; and (h) using the head internal to the disk drive and the servo write clock to write product servo sectors along the circular target path.