Compensation for non-linearity in the servo writing process by program pattern delay
View Patent ↗Hard disk servo data is recorded on a stamper master or a hard disk with a timing offset that converts the arc described by the servo data writer's rotary actuator into the arc described by the disk drive's rotary actuator.
1. A method of recording servo data, comprising:
determining a geometric offset between an arc described by a rotary servo-data writer actuator and an arc described by a rotary disk drive actuator; and
adding to a servo writing signal a timing offset according to said geometric offset, the timing offset causing the writing of servo data in the arc of a disk drive rotary actuator.
2. A method of recording servo data, comprising:
determining a geometric offset between an arc described by a rotary servo-data writer actuator and an arc described by a rotary disk drive actuator; and
adding to a servo writing signal a timing offset according to said geometric offset, the timing offset causing the writing of servo data in the arc of a the disk drive rotary actuator
wherein the servo data is recorded on a master, from which a servo data stamper can be made.
3. The method according to claim 2 wherein the geometric offset is a function of radius.
4. The method according to claim 3 wherein the geometric offset is determined for each track.
5. The method according to claim 4 wherein the timing offset is the time necessary at the rotational velocity of the servo data writer to move the servo data writing location from the arc described by the servo data writer actuator to the arc described by the disk drive actuator.
6. The method of claim 1 wherein determining the geometric offset includes determining each arc's offset from a radius index.
7. A method of recording servo data, comprising:
determining a geometric offset between an arc described by an arc described by a rotary servo-data writer actuator and an arc described by a rotary disk drive actuator, comprising:
determining each arc's offset from a radius index; and
either adding the offset of servo-writer actuator arc from the radius index or subtracting it from th offset of the disk drive actuator arc from the radius index, the addition or subtraction depending upon whether the servo data is written in a clockwise or a counterclockwise direction; and
adding to a servo writing signal a timing offset according to said geometric offset, the timing offset causing the writing of servo data in the arc of a the disk drive rotary actuator.
8. A disk drive disk having one or more servo patterns written onto the disk according to claim 1 .
9. A disk drive disk having one or more servo patterns written onto the disk according to claim 7 .
10. A master for a servo data stamper having servo patterns recorded thereon according to the method of claim 1 .
11. A master for a servo data stamper having servo patterns recorded thereon according to the method of claim 7 .