Two-dimensional magnetic recording device capable of positioning the head based on reading of first and second readers

Patent metadata

Field	Value
Publication number	US-10872630-B2
Application number	US-201916560438-A
Country	US
Kind code	B2
Filing date	Sep 4, 2019
Priority date	Dec 27, 2018
Publication date	Dec 22, 2020
Grant date	Dec 22, 2020

Abstract

According to one embodiment, a magnetic disk device includes a disk including a plurality of servo data items, a head including a write head which writes data to the disk, and a first read head and a second read head which read data from the disk, and a controller configured to position the head based on a first signal in which write data positioned between the servo data items of the disk is read by the first read head, and a second signal in which the write data is read by the second read head separated from the first read head in a radial direction of the disk.

First claim

What is claimed is:

1. A magnetic disk drive, comprising:
a disk comprising a plurality of servo data items;
a head comprising a write head which writes data to the disk, and a first read head and a second read head which read data from the disk; and
a controller configured to position the head based on a first signal in which write data positioned between the servo data items of the disk is read by the first read head, and a second signal in which the write data is read by the second read head separated from the first read head in a radial direction of the disk, wherein
the controller positions the head based on a size of the first signal and a size of the second signal, and shifts the head in a first direction from the first read head towards the second read head in the radial direction in a case where the size of the first signal decreases and the size of the second signal increases.

2. The magnetic disk drive according to claim 1 ,
wherein the controller detects the size of the first signal by performing Fourier transformation with respect to the first signal, and detects the size of the second signal by performing Fourier transformation with respect to the second signal.

3. The magnetic disk drive according to claim 1 ,
wherein a first width of the first read head in the radial direction is larger than a second width of the second read head in the radial direction.

4. The magnetic disk drive according to claim 3 ,
wherein in a case where the size of the second signal decreases without changing the size of the first signal, the controller shifts the head in a second direction from the second read head towards the first read head in the radial direction.

5. The magnetic disk drive according to claim 3 ,
wherein in a case where the size of the second signal increases without changing the size of the first signal, the controller shifts the head in a second direction from the first read head towards the second read head in the radial direction.

6. The magnetic disk drive according to claim 3 ,
wherein the first width is identical to a width of the write head in the radial direction.

7. A read processing method applied to a magnetic disk drive which comprises a disk comprising a plurality of servo data items, and a head comprising a write head which writes data with respect to the disk, and a first read head and a second read head which read data from the disk, the method comprising:
positioning the head based on a first signal in which write data positioned between the servo data items of the disk is read by the first read head, and a second signal in which the write data is read by the second read head separated from the first read head in a radial direction of the disk;
positioning the head based on a size of the first signal and a size of the second signal; and
in a case where the size of the first signal decreases, and the size of the second signal increases, shifting the head in a first direction from the first read head towards the second read head in the radial direction.

8. The read processing method according to claim 7 , further comprising:
detecting the size of the first signal by performing Fourier transformation with respect to the first signal, and detects the size of the second signal by performing Fourier transformation with respect to the second signal.

9. The read processing method according to claim 7 ,
wherein a first width of the first read head in the radial direction is larger than a second width of the second read head in the radial direction.

10. The read processing method according to claim 9 , further comprising:
in a case where the size of the second signal decreases without changing the size of the first signal, shifting the head in a second direction from the second read head towards the first read head in the radial direction.

11. The read processing method according to claim 9 , further comprising:
in a case where the size of the second signal increases without changing the size of the first signal, shifting the head in a second direction from the first read head towards the second read head in the radial direction.

12. The read processing method according to claim 9 ,
wherein the first width is identical to a width of the write head in the radial direction.

13. A magnetic disk drive, comprising:
a disk comprising a plurality of servo data items;
a head comprising a write head which writes data to the disk, and a first read head and a second read head which read data from the disk; and
a controller configured to position the head based on a first signal in which write data positioned between the servo data items of the disk is read by the first read head, and a second signal in which the write data is read by the second read head separated from the first read head in a radial direction of the disk, wherein
in a case where the size of the first signal decreases, and the size of the second signal decreases, the controller shifts the head in a second direction from the second read head towards the first read head in the radial direction.

Assignees

• Toshiba Kk
• Toshiba Electronic Devices & Storage Corp

Inventors

• Maeto Nobuhiro
• Hara Takeyori
• Kawabe Takayuki

Classifications

• G11B5/59627 Primary

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

• G11B5/59638

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

• G11B5/59633

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

• G11B5/0275

  Boundary displacement recording · CPC title

• G11B5/2654 Primary

  for recording or erasing · CPC title