# US 2008/0186629 A1 · Method of producing a magnetic disk device with servo data recorded on magnetic disk, head amplifier for magnetic disk device and disk device

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- Number: US 2008/0186629 A1
- Document ID: US20080186629A1
- Status: Published application
- Kind: A1
- Application number: 12/009,215
- Filed: 2008-01-16
- Published: 2008-08-07
- Earliest claimed: 2007-01-17
- Assignees: Hitachi Global Storage Technologies
- Inventors: Takehiko Hamaguchi; Yukiya Shimizu; Satoshi Ohki; Hideaki Maeda
- Web page: https://patentgrep.com/patent/US20080186629A1

## CPC

- G11B 5/59633: {Servo formatting (G11B5/59627, G11B5/59677, G11B5/59683, G11B5/59688 take precedence)}
- G11B 5/59666: {Self servo writing}
- G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R)

## Abstract

Embodiments of the present invention provide a method of producing a magnetic disk device in which a plurality of heads can appropriately record servo data on a magnetic disk. The method of producing the magnetic disk device according to one embodiment includes the steps of: attaching a magnetic disk, a plurality of heads and head amplifier circuit to the magnetic disk device; and recording the servo data input through the head amplifier circuit with the plurality of heads on the magnetic disk all at once; wherein the head amplifier circuit includes a plurality of amplifiers provided corresponding to the plurality of heads respectively and a plurality of registers which is provided corresponding to the plurality of amplifiers respectively and holds set values determining the amplification of the amplifiers, and the step of recording the servo data is conducted with the plurality of registers included in the head amplifier circuit individually set.

## Claims

### Claim 1

A method of producing a magnetic disk device with servo data recorded on a magnetic disk characterized by comprising the steps of:
attaching a magnetic disk, a plurality of heads, and head amplifier circuit to the magnetic disk device; and
recording the servo data input through the head amplifier circuit with the plurality of heads on the magnetic disk all at once; wherein
the head amplifier circuit includes a plurality of amplifiers which is provided corresponding to the plurality of heads respectively, amplifies and outputs recording current to the heads and the plurality of regulators which is provided corresponding to the plurality of amplifiers respectively and regulates the amplification of the amplifiers, and the step of recording the servo data is conducted with the plurality of regulators included in the head amplifier circuit individually set.

### Claim 2 (depends on 1)

The method of producing magnetic disk device with servo data recorded on a magnetic disk according to claim 1 characterized by further comprising:
a trial step of causing the plurality of heads to record data on the magnetic disk and reproduce the recorded data and determining the set values of the plurality of regulators included in the head amplifier circuit based on the obtained reproduced signals.

### Claim 3 (depends on 1)

The method of producing the magnetic disk device with servo data recorded on a magnetic disk according to claim 1, wherein
the head realizes the perpendicular magnetic recording system.

### Claim 4 (depends on 2)

The method of producing the magnetic disk device with servo data recorded on a magnetic disk according to claim 2, wherein
the head realizes the perpendicular magnetic recording system.

### Claim 5

A head amplifier circuit applied to a magnetic disk device equipped with a plurality of heads for magnetically recording data on a magnetic disk, the head amplifier circuit comprising:
a plurality of amplifiers which is provided corresponding to the plurality of heads respectively, amplifies and outputs recording current to the heads, and
a plurality of regulators which is provided corresponding to the plurality of amplifiers respectively and regulates the amplification of the amplifiers.

### Claim 6

A magnetic disk device comprising:
a magnetic disk;
a plurality of heads for magnetically recording data on the magnetic disk; and
a head amplifier circuit comprising:
a plurality of amplifiers which is provided corresponding to the plurality of heads respectively, amplifies and outputs recording current to the heads, and
a plurality of regulators which is provided corresponding to the plurality of amplifiers respectively and regulates the amplification of the amplifiers.

### Claim 7 (depends on 6)

The magnetic disk device of claim 6 wherein:
the plurality of heads record data on the magnetic disk and reproduce the recorded data and determining the set values of the plurality of regulators included in the head amplifier circuit based on obtained reproduced signals.

### Claim 8 (depends on 6)

The magnetic disk device of claim 6 wherein
servo data is recorded on a magnetic disk, and
wherein the head realizes the perpendicular magnetic recording system.

### Claim 9 (depends on 7)

The magnetic disk device of claim 7 wherein
servo data is recorded on a magnetic disk, and
wherein the head realizes the perpendicular magnetic recording system.