Patent ID: 7433143

Claim:
A method of writing product servo sectors to a disk of a disk drive to define a plurality of data tracks, the disk drive comprising control circuitry and a head disk assembly (HDA) comprising the disk, an actuator arm, a head coupled 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) writing a first plurality of spiral tracks having a first slope to a first disk surface, wherein each spiral track comprises a high frequency signal interrupted at a predetermined interval by a sync mark; (b) writing a second plurality of spiral tracks having a second slope substantially steeper than the first slope to a second disk surface, wherein each spiral track comprises a high frequency signal interrupted at a predetermined interval by a sync mark; (c) using the head internal to the disk drive to read the spiral tracks to generate a read signal; (d) processing the read signal to detect the sync marks in the spiral tracks to synchronize a servo write clock; (e) 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 first target circular path; and (f) using the head internal to the disk drive and the servo write clock to write product servo sectors along the first target circular path; wherein the steeper slope of the second plurality of spiral tracks causes a track density of the data tracks to be lower on the second disk surface compared to the track density of the data tracks on the first disk surface.