Patent ID: 7929238

Claim:
A disk drive comprising: a disk comprising a plurality of servo sectors defining a plurality of servo tracks, wherein: each servo sector comprises a servo sync mark; the servo tracks form a plurality of servo zones; and a servo data rate of the servo sectors in a first servo zone is different than a servo data rate of the servo sectors in a second servo zone; a head actuated radially over the disk for generating a read signal; and control circuitry operable to: generate a fixed rate clock; generate a disk locked clock synchronized to the servo data rate of the servo zone the head is over; use the disk locked clock to generate a servo timing window relative to a circumferential location of the head and the servo sectors; seek the head from the first servo zone to the second servo zone; and switch to the fixed rate clock to generate the servo timing window while the head transitions from the first servo zone to the second servo zone.