Patent ID: 8432629

Claim:
A disk drive comprising: a disk comprising a plurality of spiral tracks, each spiral track comprising a high frequency signal interrupted at a predetermined interval by a sync mark; a head actuated over the disk; and control circuitry operable to: use the head to read the spiral tracks to generate a read signal representing spiral track crossings; first open a first sync frame in response to a first frame offset during a first revolution of the disk, wherein the first sync frame corresponds to the head approaching a first sync mark in a first spiral track crossing; generate a first sync frame position error signal (PES) representing a difference between a target framing of the first sync frame around the first sync mark and a detected framing of the first sync frame around the first sync mark; adjust the first frame offset in response to the first sync frame PES; and second open the first sync frame in response to the adjusted first frame offset during a second revolution of the disk.