Magnetic head having difference skew angles at different regions on magnetic recording disk

Patent metadata

Field	Value
Publication number	US-10600437-B2
Application number	US-201816111927-A
Country	US
Kind code	B2
Filing date	Aug 24, 2018
Priority date	Mar 22, 2018
Publication date	Mar 24, 2020
Grant date	Mar 24, 2020

Abstract

According to one embodiment, a magnetic disk device includes a disk including a first region and a second region different from the first region, a head that writes data on the disk and reads data from the disk, an actuator that positions the head on the disk, and a controller which positions the head by driving the actuator and writes data in the first region and the second region with the head, a skew angle of the head with respect to a circumferential direction of the disk varying within a first angle in the first region, and varying, in the second region, from a second angle larger than the first angle to a third angle larger than the first angle and the second angle.

First claim

What is claimed is:

1. A magnetic disk device comprising:
a disk including a first region and a second region different from the first region;
a head that writes data on the disk and reads data from the disk;
an actuator that positions the head on the disk; and
a controller which positions the head by driving the actuator and writes data in the first region and the second region with the head,
a skew angle of the head with respect to a circumferential direction of the disk varying within a first angle in the first region, and varying, in the second region, from a second angle larger than the first angle to a third angle larger than the first angle and the second angle,
the controller writes first data to be accessed at a first number of times in a first period in the first region, and writes second data to be accessed at a second number of times smaller than the first number of times in the first period in the second region.

2. The magnetic disk device according to claim 1 , wherein the third angle θtd(r) is an angle in a range of θs(r)−θth≤θtd(r)≤θs(r) at a radial position r of the disk, θs(r) is an skew angle at the radial position r, θth is an angle that ensures a quality of write/read processing, and when a difference angle θdf between the skew angle θs(r) at the radial position r and the third angle θtd(r) is an angle in a range of 0≤|θdf(r)|≤θth, the controller writes data at the third angle θtd(r) with respect to the circumferential direction at the radial position r.

3. The magnetic disk device according to claim 1 ,
wherein
the first data includes the first user data to be accessed at the first number of times in the first period, and
the second data include at least one of media cache data, system information, and the second user data to be accessed at the second number of times in the first period.

4. The magnetic disk device according to claim 1 , wherein the controller writes data in the second region so that at least one of a linear recording density and a track density is lower in the second region than in the first region.

5. A magnetic disk device comprising:
a disk including a first region and a second region different from the first region;
a head that writes data on the disk and reads data from the disk;
an actuator that positions the head on the disk; and
a controller which positions the head by driving the actuator and writes data in the first region and the second region with the head,
a skew angle of the head with respect to a circumferential direction of the disk varying within a first angle in the first region, and varying, in the second region, from a second angle larger than the first angle to a third angle larger than the first angle and the second angle;
wherein the controller writes data in a spiral shape and at a fourth angle with respect to the circumferential direction in the second region.

6. A magnetic disk device comprising:
a disk including a first region and a second region different from the first region;
a head that writes data on the disk and reads data from the disk;
an actuator that positions the head on the disk; and
a controller which positions the head by driving the actuator and writes data in the first region and the second region with the head,
a skew angle of the head with respect to a circumferential direction of the disk varying within a first angle in the first region, and varying, in the second region, from a second angle larger than the first angle to a third angle larger than the first angle and the second angle;
wherein the controller writes data in a spiral shape and according to the skew angle in the second region.

7. The magnetic disk device according to claim 6 , wherein the controller writes the first data so that a difference value between the skew angle and a fourth angle of the first data with respect to the circumferential direction is zero in the second region.

8. The magnetic disk device according to claim 6 , wherein the controller writes the first data so that a difference value between the skew angle and the fourth angle of the first data with respect to the circumferential direction is smaller than the second angle in the second region.

9. The magnetic disk device according to claim 6 , wherein the controller writes the first data so that a difference value between the skew angle and the fourth angle of the first data with respect to the circumferential direction is equal to the second angle in the second region.

Assignees

• Toshiba Kk
• Toshiba Electronic Devices & Storage Corp

Inventors

• Sudo Daisuke
• Sasamoto Tatsurou
• Hara Takeyori
• Takeo Akihiko
• Chokki Kazuo
• Nitta Tatsuo

Classifications

• G11B2020/1238

  track, i.e. the entire a spirally or concentrically arranged path on which the recording marks are located · CPC title

• G11B20/20

  for correction of skew for multitrack recording · CPC title

• G11B20/1217

  on discs · CPC title

• G11B5/59633

  Servo formatting (G11B5/59627, G11B5/59677, G11B5/59683, G11B5/59688 take precedence) · CPC title

• G11B5/54

  with provision for moving the head into or out of its operative position or across tracks · CPC title