Servo writing substantially linear servo wedges to reduce overwrite effect in perpendicular magnetic recording
View Patent ↗A disk drive is disclosed comprising a disk having a plurality of servo sectors forming a plurality of substantially linear servo wedges extending from an outer diameter of the disk to an inner diameter of the disk, wherein each servo sector is written using perpendicular magnetic recording. The disk drive further comprises a head coupled to a distal end of an actuator arm that is rotated by a rotary actuator about a pivot in order to actuate the head radially over the disk in a substantially arcuate path.
1. A disk drive comprising:
(a) a disk comprising a plurality of servo sectors forming a plurality of substantially linear servo wedges extending from an outer diameter of the disk to an inner diameter of the disk, wherein each servo sector is written using perpendicular magnetic recording;
(b) an actuator arm;
(c) a head coupled to a distal end of the actuator arm;
(d) a rotary actuator for rotating the actuator arm about a pivot in order to actuate the head radially over the disk in a substantially arcuate path; and wherein each servo sector comprises a servo sync mark and the disk drive further comprises control circuitry for: (a1) generating a sync mark detection window commensurate with the head approaching a servo sync mark; and (b) adjusting the sync mark detection window relative to a radial location of the head with respect to the disk.
2. The disk drive as recited in claim 1 , wherein:
(a) the control circuitry performs a seek operation to seek the head from a current track to a target track; and
(b) the control circuitry adjusts the sync mark detection window by computing a sync window offset in response to the current track and the target track.
3. A method of detecting a servo sync mark in a servo sector recorded on a disk of a disk drive, the disk drive comprising a disk having a plurality of servo sectors forming a plurality of substantially linear servo wedges extending from an outer diameter of the disk to an inner diameter of the disk, a rotary actuator for rotating an actuator arm about a pivot in order to actuate a head over the disk in a substantially arcuate path, the method comprising the steps of:
(a) generating a sync mark detection window commensurate with the head approaching a servo sync mark of a servo sector in one of the substantially linear servo wedges; and
(b) adjusting the sync mark detection window relative to a radial location of the head with respect to the disk.
4. The method as recited in claim 3 , wherein the step of adjusting the sync mark detection window comprises the step of computing a sync window offset in response to a current track the head is currently over and a target track of a seek operation.