Method and apparatus for writing servo information on a recording medium

Patent metadata

Field	Value
Publication number	US-9275654-B2
Application number	US-201514827822-A
Country	US
Kind code	B2
Filing date	Aug 17, 2015
Priority date	Feb 17, 2012
Publication date	Mar 1, 2016
Grant date	Mar 1, 2016

Abstract

A servo system for writing servo information on a recording medium of a hard disk drive and for determining head position based on the servo information with a tracking accuracy, the servo system including a first magnetic head and a servo writer. The servo writer is configured to write the servo information on the recording medium by forming, using the first magnetic head, a first servo pattern comprising a servo burst pattern on a segment of a first track of a first layer of the recording medium; and by forming a second servo pattern comprising addressing information on a segment of a second track of a second layer of the recording medium. The second track is arranged half a width of the first track from the first track to increase the tracking accuracy of the servo system.

First claim

What is claimed is:

1. A servo system for writing servo information on a recording medium of a hard disk drive and for determining head position based on the servo information with a tracking accuracy, the servo system comprising:
a first magnetic head; and
a servo writer configured to write the servo information on the recording medium of the hard disk drive by:
forming, using the first magnetic head, a first servo pattern comprising a servo burst pattern on a segment of a first track of a first layer of the recording medium of the hard disk drive; and
forming a second servo pattern comprising addressing information on a segment of a second track of a second layer of the recording medium of the hard disk drive,
wherein the second track is arranged half a width of the first track from the first track; and
wherein arranging the second track half the width of the first track from the first track increases the tracking accuracy of the servo system.

2. The servo system of claim 1 , wherein the servo writer is further configured to:
form a third servo pattern comprising a subsequent servo burst pattern on a segment of a third track of the first layer of the recording medium,
wherein the third track is arranged from the second track by half a width of the second track.

3. The servo system of claim 2 , wherein the second track is between the first track and the third track.

4. The servo system of claim 2 , wherein:
the servo burst pattern is of a first frequency; and
the subsequent servo burst pattern is of a second frequency.

5. The servo system of claim 2 , wherein the servo burst pattern and the subsequent servo burst pattern is of a single frequency.

6. The servo system of claim 1 , wherein the addressing information comprises automatic gain control (AGC), sector address mark (SAM), and GrayCode.

7. The servo system of claim 1 , wherein the second layer is arranged over the first layer.

8. The servo system of claim 1 , wherein the servo writer is further configured to form an intermediate servo pattern comprising the addressing information on a subsequent segment of the first track of the first layer of the recording medium.

9. The servo system of claim 8 , wherein the servo writer is further configured to:
form the first servo pattern comprising the servo burst pattern on the segment of the first track of the first layer of the recording medium during a writing pass of the first magnetic head; and
form the intermediate servo pattern comprising the addressing information on the subsequent segment of the first track of the first layer of the recording medium during the writing pass of the first magnetic head.

10. The servo system of claim 9 , wherein the first magnetic head includes a wide head.

11. The servo system of claim 9 , wherein the servo writer is further configured to form the second servo pattern comprising addressing information on the segment of the second track of the second layer of the recording medium during a subsequent writing pass of a second magnetic head.

12. The servo system of claim 11 , wherein the second magnetic head includes a head other than a wide head.

13. The servo system of claim 11 , wherein the servo writer is further configured to use the intermediate servo pattern formed on the subsequent segment of the first track of the first layer of the recording medium as a reference during the writing pass when forming the second servo pattern on the segment of the second track of the second layer during the subsequent writing pass.

14. The servo system of claim 11 , wherein the intermediate servo pattern formed on the subsequent segment of the first track of the first layer of the recording medium during the writing pass is distorted when forming the second servo pattern on the segment of the second track of the second layer during the subsequent writing pass.

15. The servo system of claim 1 , wherein the second layer is arranged over the first layer, and wherein the servo writer is further configured to form the second servo pattern comprising addressing information on a portion of the first layer below the segment of the second track of the second layer.

16. The servo system of claim 15 , wherein the servo writer is further configured to form in a single writing pass, the first servo pattern comprising the servo burst pattern on the segment of the first track of the first layer, the second servo pattern comprising addressing information on the segment of the first track of the first layer, and the second servo pattern comprising addressing information on the segment of the second track of the second layer.

17. The servo system of claim 16 , wherein the servo writer is further configured to perform the single writing pass using the first magnetic head, and wherein the first magnetic head includes a wide head.

Assignees

• Marvell Int Ltd

Inventors

• Wong Chiew Leong
• Alexopoulos Pantelis
• Yuan Zhimin
• Ong Chun Lian

Classifications

• G11B5/012 Primary

  Recording on, or reproducing or erasing from, magnetic disks (G11B17/00, G11B19/00 take precedence) · CPC title

• G11B5/59638

  Servo formatting apparatuses, e.g. servo-writers · CPC title

• G11B5/5965

  Embedded servo format (G11B5/59655 takes precedence) · CPC title

• G11B5/59655

  Sector, sample or burst servo format · CPC title

• G11B5/82

  Disk carriers · CPC title