Servo writing a disk drive by integrating a spiral track read signal
AssigneeWestern Digital Technologies, Inc.
InventorsTehri S. Lee, Siri S. Weerasooriya
Life of this patent
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Abstract
A method of writing product servo sectors to a disk of a disk drive is disclosed. The disk comprises a plurality of spiral tracks, wherein each spiral track comprises a high frequency signal interrupted by a sync mark at a sync mark interval. The head internal to the disk drive is used to read the spiral tracks to generate a read signal. The read signal is integrated to generate a ramp signal, wherein a position error signal is generated from the ramp signal. The position error signal is used to maintain the head internal to the disk drive along a servo track while writing product servo sectors along the servo track.
Claims14
A method of writing product servo sectors to a disk of a disk drive, the disk drive comprising control circuitry and a head disk assembly (HDA) comprising the disk, an actuator arm, a head coupled to a distal end of the actuator arm, and a voice coil motor for rotating the actuator arm about a pivot to position the head radially over the disk, the disk comprising a plurality of spiral tracks, wherein each spiral track comprises a high frequency signal interrupted by a sync mark at a sync mark interval, the method comprising the steps of:
- (a) using the head internal to the disk drive to read the spiral tracks to generate a read signal;
- (b) integrating the read signal to generate a ramp signal representing a spiral track crossing;
- (c) generating a position error signal in response to the ramp signal, wherein the position error signal is generated relative to a difference between a target amplitude at the reference point of the ramp signal and an actual amplitude of the ramp signal when the target sync mark is detected;
- (d) using the position error signal to maintain the head internal to the disk drive along a servo track while writing product servo sectors along the servo track.
A disk drive comprising:
- (a) a disk comprising a plurality of spiral tracks, wherein each spiral track comprises a high frequency signal interrupted by a sync mark at a sync mark interval;
- (b) a head actuated over the disk;
- and
- (c) control circuitry for writing a plurality of product servo sectors to the disk to define a plurality of radially spaced, concentric data tracks by:
- using the head internal to the disk drive to read the spiral tracks to generate a read signal;
- integrating the read signal to generate a ramp signal representing a spiral track crossing;
- generating a position error signal in response to the ramp signal, wherein the control circuitry generates the position error signal relative to a difference between a target amplitude at the reference point of the ramp signal and an actual amplitude of the ramp signal when the target sync mark is detected;
- using the position error signal to maintain the head internal to the disk drive along a servo track while writing product servo sectors along the servo track.
Dependencies are inferred from the claim text.