Patent ID: 7502195

Claim:
A method of writing M spiral tracks (i=1 to M) to a disk of a disk drive, the method comprising: positioning a head over a first radial location; writing a first concentric reference track at the first radial location, the first concentric reference track comprising N concentric servo sectors; prior to writing one of the spiral tracks: positioning the head over the first concentric reference track, reading the concentric servo sectors in the first concentric reference track, and generating a position error signal first_PES 0 (n) for each servo sector (n=1 to N) representing an offset from the first radial location; positioning the head over the first concentric reference track and reading the first concentric reference track; generating a position error signal first_PES i (j) for at least one of the servo sectors j in the first concentric reference track, wherein the first_PES i (j) represents an offset of the head from the first radial location, and the servo sector j corresponds to a circumferential location of the spiral track; generating a distance delta D_Δ relative to a difference between the first_PES 0 (j) and the first_PES i (j), wherein at least one of a starting radial location and a velocity profile is adjusted in response to the distance delta D_Δ; and writing the spiral track to the disk using the starting radial location and the velocity profile.