Magnetic disk device and control method of servo write

Patent metadata

Field	Value
Publication number	US-11011199-B2
Application number	US-202016752969-A
Country	US
Kind code	B2
Filing date	Jan 27, 2020
Priority date	Jun 14, 2019
Publication date	May 18, 2021
Grant date	May 18, 2021

Abstract

According to one embodiment, a magnetic disk device including a disk, a head, and a controller configured to, when writing a first servo sector, a second servo sector, and a third servo sector in the order described according to a second route varying in a radial direction of the disk with respect to a first route, adjust first timing used to write the second servo sector next to the first servo sector, and adjust second timing used to write the third servo sector next to the second servo sector.

First claim

What is claimed is:

1. A magnetic disk device comprising:
a disk;
a head configured to write data to the disk or read data from the disk; and
a controller configured to, when writing a first servo sector, a second servo sector, and a third servo sector in the order described according to a second route varying in a radial direction of the disk with respect to a first route and extending in a circumferential direction of the disk,
adjust first timing used to write the second servo sector next to the first servo sector in such a manner that a first servo interval between the first servo sector and the second servo sector on the second route corresponds to a first interval between the first servo sector and the second servo sector on the first route, and
adjust second timing used to write the third servo sector next to the second servo sector in such a manner that a second servo interval between the second servo sector and the third servo sector on the second route corresponds to a second interval between the second servo sector and the third servo sector on the first route.

2. The magnetic disk device of claim 1 , wherein the controller acquires the second route, the first servo interval, and the second servo interval from a table.

3. The magnetic disk device of claim 2 , wherein the table includes the second route, third servo intervals between servo sectors of a first servo track to be written according to the second route in such a manner that intervals between the servo sectors at the time when accessing is carried out according to the first route become equal, and fourth servo intervals between servo sectors of a second servo track to be written next to the first servo track according to the second route in such a manner that intervals of the servo sectors at the time when accessing is carried out according to the first route after writing servo sectors according to the second route next to the first servo track become equal.

4. The magnetic disk device of claim 3 , wherein the controller updates the fourth servo intervals during a seek of the head or in a background process.

5. The magnetic disk device of claim 2 , wherein the controller writes servo tracks according to the second route for each zone formed by dividing the disk in the radial direction, and records servo intervals measured with respect to the second route and the servo tracks as a table.

6. The magnetic disk device of claim 1 , wherein the first route is concentric with the disk.

7. The magnetic disk device of claim 6 , wherein the second route is sinusoidal.

8. The magnetic disk device of claim 6 , wherein the second route possesses a form of a triangular wave.

9. The magnetic disk device of claim 1 , wherein the first interval and the second interval are equal to each other.

10. The magnetic disk device of claim 1 , wherein the first servo interval and the second servo interval are different from each other.

11. A control method of servo write to be applied to a magnetic disk device including a disk, and a head configured to write data to the disk or read data from the disk, comprising:
adjusting, when writing a first servo sector, a second servo sector, and a third servo sector in the order described according to a second route varying in a radial direction of the disk with respect to a first route and extending in a circumferential direction of the disk, first timing used to write the second servo sector next to the first servo sector in such a manner that a first servo interval between the first servo sector and the second servo sector on the second route corresponds to a first interval between the first servo sector and the second servo sector on the first route;
and adjusting second timing used to write the third servo sector next to the second servo sector such a manner that a second servo interval between the second servo sector and the third servo sector on the second route corresponds to a second interval between the second servo sector and the third servo sector on the first route.

12. The control method of servo write of claim 11 , further comprising:
acquiring the second route, the first servo interval, and the second servo interval from a table.

13. The control method of servo write of claim 12 , wherein the table includes the second route, third servo intervals between servo sectors of a first servo track to be written according to the second route in such a manner that intervals between the servo sectors at the time when accessing is carried out according to the first route become equal, and fourth servo intervals between servo sectors of a second servo track to be written next to the first servo track according to the second route in such a manner that intervals of the servo sectors at the time when accessing is carried out according to the first route after writing servo sectors according to the second route next to the first servo track become equal.

14. The control method of servo write of claim 13 , further comprising:
updating the fourth servo intervals during a seek of the head or in a background process.

15. The control method of servo write of claim 12 , further comprising:
writing servo tracks according to the second route for each zone formed by dividing the disk in the radial direction, and recording servo intervals measured with respect to the second route and the servo tracks as a table.

16. The control method of servo write of claim 11 , wherein the first interval and the second interval are equal to each other.

17. The control method of servo write of claim 11 , wherein the first servo interval and the second servo interval are different from each other.

Assignees

• Toshiba Kk
• Toshiba Electronic Devices & Storage Corp

Inventors

• Sudo Daisuke
• Hara Takeyori

Classifications

• G11B5/59627 Primary

  Aligning for runout, eccentricity or offset compensation (G11B5/5534, G11B5/59677, G11B5/59688 take precedence) · CPC title

• G11B5/59655 Primary

  Sector, sample or burst servo format · CPC title

• G11B5/5547

  "Seek" control and circuits therefor (G11B5/5556 takes precedence) · CPC title

• G11B5/5508 Primary

  Control circuits therefor (G11B5/5513 takes precedence) · CPC title

• G11B21/106

  on disks · CPC title