# US 12,014,757 B2 · Magnetic disk device

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- Number: US 12,014,757 B2
- Document ID: US12014757B2
- Status: Granted
- Kind: B2
- Application number: 18/169,407
- Filed: 2023-02-15
- Published: 2024-03-21
- Granted: 2024-06-18
- Earliest claimed: 2022-09-16
- Assignees: Kabushiki Kaisha Toshiba; Toshiba Electronic Devices & Storage Corporation
- Applicants: Kabushiki Kaisha Toshiba; Toshiba Electronic Devices & Storage Corporation
- Inventors: Shinichi Kobatake; Toru Watanabe; Masami Yamane
- Web page: https://patentgrep.com/patent/US12014757B2

## CPC

- G11B 5/5547: {"Seek" control and circuits therefor (G11B5/5556 takes precedence)}
- G11B 5/012: Recording on, or reproducing or erasing from, magnetic disks (G11B17/00, G11B19/00 take precedence)
- G11B 19/28: Speed controlling, regulating, or indicating (G11B19/24 takes precedence)
- 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

According to one embodiment, a disk device includes a rotatable magnetic disk, an actuator which supports and moves a head, a ramp which holds the head at an unloaded position, a motor which rotates the magnetic disk, and a controller which performs a load operation and a seek operation. When a radial travel speed of the head during the load operation is referred to as Vr1, a circumferential travel speed of the head is referred to as Vt1, a radial travel speed of the head during the seek operation is referred to as Vrs, and a circumferential travel speed is referred to as Vts, the controller controls at least one of the radial travel speed of the head and number of revolutions of the magnetic disk to satisfy a relationship (Vr1/Vt1)<(Vrs/Vts).

## Claims

### Claim 1

A disk device comprising:
a rotatable magnetic disk;
an actuator which supports and moves a head in a radial direction of the magnetic disk;
a ramp which holds the head at an unloaded position on an outer circumferential side of the magnetic disk;
a motor which rotates the magnetic disk; and
a controller which performs a load operation of loading the head from the ramp onto the magnetic disk and a whole surface seek operation of moving the head from an outermost circumference to an innermost circumference of the magnetic disk after loading, at an activation of the disk device, and which when a radial travel speed of the head during the load operation is referred to as Vr1, a circumferential travel speed of the head based on rotation of the magnetic disk during the load operation is referred to as Vt1, a radial travel speed of the head during the whole surface seek operation is referred to as Vrs, and a circumferential travel speed of the head during the whole surface seek operation is referred to as Vts, controls at least one of the radial travel speed of the head and number of revolutions of the magnetic disk to satisfy a relationship (Vr1/Vt1)<(Vrs/Vts).

### Claim 2 (depends on 1)

The disk device of claim 1, wherein
the controller sets the circumferential travel speed Vts of the head during the whole surface seek operation to be slower than the circumferential travel speed Vt1 of the head during the load operation to satisfy the relationship (Vr1/Vt1)<(Vrs/Vts).

### Claim 3 (depends on 2)

The disk device of claim 2, wherein
the controller reduces the number of revolutions of the motor to make the circumferential travel speed Vts slower.

### Claim 4 (depends on 1)

The disk device of claim 1, wherein
the controller sets the radial travel speed Vrs of the head during the whole surface seek operation to be faster than the radial travel speed Vr1 of the head during the load operation to satisfy the relationship (Vr1/Vt1)<(Vrs/Vts).

### Claim 5 (depends on 1)

The disk device of claim 1, wherein
the controller sets the circumferential travel speed Vts of the head during the whole surface seek operation to be slower than the circumferential travel speed Vt1 of the head during the load operation, and sets the radial travel speed Vrs of the head during the whole surface seek operation to be faster than the radial travel speed Vr1 of the head during the load operation to satisfy the relationship (Vr1/Vt1)<(Vrs/Vts).

### Claim 6 (depends on 1)

The disk device of claim 1, wherein
the controller moves the head on a whole surface of the magnetic disk from an outer circumference to an inner circumference in a state in which the relationship (Vr1/Vt1)<(Vrs/Vts) is satisfied, during the whole surface seek operation.