Patent ID: 6992848

Claim:
A method of writing product servo bursts 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 periodically writing a plurality of reference servo bursts to the disk along a plurality of substantially spiral paths to form a plurality of spiral reference patterns; (d) removing the head positioning pin from the HDA; and (e) using the head internal to the disk drive to read the reference servo bursts in the spiral reference patterns in order to write the product servo bursts to the disk, thereby defining a plurality of radially spaced, concentric data tracks.