Patent ID: 7916416

Claim:
A disk drive comprising: a disk comprising servo data defining a plurality of servo tracks, wherein the servo data comprises: a preamble comprising a varying length across a radius of the disk; and a plurality of slanted line servo bursts recorded at a tilt angle with respect to the preamble, wherein the tilt angle varies across the radius of the disk commensurate with the varying length of the preamble; a head actuated radially over the disk for generating a read signal; and control circuitry operable to: generate a preamble read signal when the head passes over the preamble; generate a burst read signal when the head passes over at least one of the slanted line servo bursts; generate a position error signal (PES) in response to a phase difference between the preamble read signal and the burst read signal; and position the head in response to the PES, wherein: the burst read signal comprises a periodic signal; the burst read signal comprises a burst length representing a period of the periodic signal; the burst length varies across the radius of the disk commensurate with the varying length of the preamble; the tilt angle varies across the radius of the disk according to: a tan(BL/BTP) where BL represents the burst length and BTP represents a track pitch of the slanted line servo bursts.