Disk drive comprising slanted line servo burst sets offset radially
View Patent ↗A disk drive is disclosed comprising a disk having servo data defining a plurality of servo tracks. The servo data comprises a preamble, and a plurality of slanted line servo bursts recorded at a tilt angle with respect to the preamble. The slanted line servo bursts comprises a first plurality of slanted line servo bursts and a second plurality of slanted line servo bursts, wherein the second plurality of slanted line servo bursts are offset radially from the first plurality of slanted line servo bursts. A position error signal (PES) is generated in response to a phase difference when reading the preamble and the slanted line servo bursts.
1. A disk drive comprising:
a disk comprising servo data defining a plurality of servo tracks, wherein the servo data comprises:
a preamble comprising a varying length across a radius of the disk; and
a plurality of slanted line servo bursts recorded at a tilt angle with respect to the preamble, wherein:
the slanted line servo bursts comprises a first plurality of slanted line servo bursts and a second plurality of slanted line servo bursts; and
the second plurality of slanted line servo bursts are offset radially from the first plurality of slanted line servo bursts by a fraction of a servo track;
a head actuated radially over the disk for generating a read signal; and
control circuitry operable to:
generate a preamble read signal when the head passes over the servo data preamble;
generate a burst read signal when the head passes over at least one of the slanted line servo bursts;
generate a position error signal (PES) in response to a phase difference between the preamble read signal and the burst read signal; and
position the head in response to the PES.
2. The disk drive as recited in claim 1 , wherein the second plurality of slanted line servo bursts are offset by a half track pitch of a servo track.
3. The disk drive as recited in claim 1 , wherein the servo data is recorded on the disk by fabricating magnetic slants and non-magnetic grooves.
4. The disk drive as recited in claim 1 , wherein the servo data is recorded on the disk by stamping a servo pattern on the disk using a master stamping disk.
5. A method of writing servo data to define a plurality of servo tracks on a disk of a disk drive comprising:
recording a preamble; and
recording a plurality of slanted line servo bursts at a tilt angle with respect to the preamble, wherein:
the slanted line servo bursts comprises a first plurality of slanted line servo bursts and a second plurality of slanted line servo bursts; and
the second plurality of slanted line servo bursts are offset radially from the first plurality of slanted line servo bursts by a fraction of a servo track.
6. The method as recited in claim 5 , wherein the second plurality of slanted line servo bursts are offset by a half track pitch of a servo track.
7. The method as recited in claim 5 , wherein the servo data is recorded on the disk by fabricating magnetic slants and non-magnetic grooves.
8. The method as recited in claim 5 , wherein the servo data is recorded on the disk by stamping a servo pattern on the disk using a master stamping disk.
9. A disk for use in a disk drive, the disk comprising servo data defining a plurality of servo tracks, the servo data comprising:
a preamble comprising a varying length across a radius of the disk; and
a plurality of slanted line servo bursts recorded at a tilt angle with respect to the preamble, wherein:
the slanted line servo bursts comprises a first plurality of slanted line servo bursts and a second plurality of slanted line servo bursts; and
the second plurality of slanted line servo bursts are offset radially from the first plurality of slanted line servo bursts by a fraction of a servo track.
10. The disk as recited in claim 9 , wherein the second plurality of slanted line servo bursts are offset by a half track pitch of a servo track.
11. The disk as recited in claim 9 , wherein the servo data is recorded on the disk by fabricating magnetic slants and non-magnetic grooves.
12. The disk as recited in claim 9 , wherein the servo data is recorded on the disk by stamping a servo pattern on the disk using a master stamping disk.