Propagation self servowrite using self-written spiral signals for in-process calibration
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorRichard M. Ehrlich
Life of this patent
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Abstract
The operation of propagation self servowrite can be improved by using spirals written upon the disk. The spirals can be used to reduce the DC drift of the propagation of the self servowrite. The writing of the spirals can be improved by using the back EMF signal for the VCM to control the velocity of the actuator during the writing of the spirals to produce a more consistent spiral shape. Additionally, back EMF crossings of the spindle can be used to space the spirals evenly about the disk.
Claims16
A disk drive comprising:
- an actuator including a write element and a read element;
- and
- a controller to produce control signals for the actuator, the controller writing spirals on a disk of the disk drive, and propagation self servowriting on the disk, the self-servowriting propagating servo wedges using previously written servo wedges, the spirals being used to adjust the self-servo writing.
A disk drive comprising:
- an actuator including a write element and a read element;
- and
- a controller to produce control signals for the actuator, the controller writing spirals on a disk of the disk drive, the spiral writing including controlling the velocity of the actuator unit during the writing of the spirals using the actuator back EMF as feedback, the controller using the spirals during self servowriting.
A disk drive comprising:
- an actuator including a write element and a read element;
- and
- a controller to produce control signals for the actuator, the controller writing spirals on a disk of the disk drive, the spiral writing including spacing the spirals using spindle back EMF zero-crossings, the controller using the spirals during self servowriting.
A method of servowriting a disk of a disk drive comprising:
- writing spirals on a disk;
- propagation self servowriting on the disk, the self-servowriting propagating servo wedges using previously written servo wedges, the spirals being used to adjust the self-servo writing.
Dependencies are inferred from the claim text.