Magnetic disk device and method of reordering process

Patent metadata

Field	Value
Publication number	US-11507315-B2
Application number	US-202017004281-A
Country	US
Kind code	B2
Filing date	Aug 27, 2020
Priority date	Nov 12, 2019
Publication date	Nov 22, 2022
Grant date	Nov 22, 2022

Abstract

According to one embodiment, a magnetic disk device includes a first disk, a second disk, a first head, a second head, a first actuator including the first head, a second actuator including the second head, a first arithmetic unit executing a first reordering process of a command stored in a first queue corresponding to the first actuator, and a second arithmetic unit executing a second reordering process of a command stored in a second queue corresponding to the second actuator, the first arithmetic unit executing the second reordering process, the second arithmetic unit executing the first reordering process.

First claim

What is claimed is:

1. A magnetic disk device, comprising:
a first disk;
a second disk;
a first head writing data to the first disk and reading data from the first disk;
a second head writing data to the second disk and reading data from the second disk;
a first actuator comprising the first head;
a second actuator comprising the second head;
a first arithmetic unit executing a first reordering process of a command stored in a first queue corresponding to the first actuator; and
a second arithmetic unit executing a second reordering process of a command stored in a second queue corresponding to the second actuator,
the first arithmetic unit executing the second reordering process,
the second arithmetic unit executing the first reordering process, wherein
the first arithmetic unit executes the second reordering process when a command number stored in the first queue is smaller than or equal to a first lower limit and a command number stored in the second queue is larger than or equal to a first upper limit, and
the second arithmetic unit executes the first reordering process when the command number stored in the second queue is smaller than or equal to a second lower limit and the command number stored in the first queue is larger than or equal to a second upper limit.

2. The magnetic disk device of claim 1 , wherein
the first arithmetic unit transfers first information for the first reordering process to the second arithmetic unit when the command number stored in the second queue is smaller than or equal to the second lower limit and the command number stored in the first queue is larger than or equal to the second upper limit, and
the second arithmetic unit transfers second information for the second reordering process to the first arithmetic unit when the command number stored in the first queue is smaller than or equal to the first lower limit and the command number stored in the second queue is larger than or equal to the first upper limit.

3. The magnetic disk device of claim 2 , wherein
the first information includes information on a position of a data sector of the first disk on which the first head is arranged, and information on positions of a plurality of data sectors of the first disk, which are specified by a plurality of commands stored in the first queue, respectively, and
the second information includes information on a position of a data sector of the second disk on which the second head is arranged, and information of positions of a plurality of data sectors of the second disk, which are specified by a plurality of commands stored in the second queue, respectively.

4. The magnetic disk device of claim 1 , wherein
the first lower limit is smaller than the first upper limit, and the second lower limit is smaller than the second upper limit.

5. The magnetic disk device of claim 1 , wherein
the command numbers stored in the first queue and the second queue are larger than or equal to zero.

6. A magnetic disk device, comprising:
a first disk;
a second disk;
a first head writing data to the first disk and reading data from the first disk;
a second head writing data to the second disk and reading data from the second disk;
a first actuator comprising the first head;
a second actuator comprising the second head;
a first arithmetic unit executing a first reordering process of a command stored in a first queue corresponding to the first actuator; and
a second arithmetic unit executing a second reordering process of a command stored in a second queue corresponding to the second actuator,
the first arithmetic unit executing the second reordering process,
the second arithmetic unit executing the first reordering process, wherein
based on a plurality of commands stored in the second queue, the first arithmetic unit calculates a plurality of first access costs equivalent to times to arrange the second head from positions of a plurality of data sectors that correspond to the plurality of commands stored in the second queue, respectively, to positions of a plurality of different data sectors that correspond to a plurality of different commands, respectively, of the plurality of commands stored in the second queue, and transfers the plurality of first access costs to the second arithmetic unit, and
the second arithmetic unit stores the plurality of commands in the second queue, calculates each of a plurality of second access costs equivalent to times to arrange the second head from a current position of a data sector of the second head to positions of a plurality of data sectors stored in the second queue, and selects a command to be next processed, based on the plurality of first access costs and the plurality of second access costs.

7. The magnetic disk device of claim 6 , wherein
the positions of the data sectors are represented by a combination of at least two of a cylinder number, a head number, a sector number, a position of the first disk or the second disk in a radial direction, and an angle of the first disk or the second disk.

8. The magnetic disk device of claim 6 , wherein
the first access costs include a plurality of seek times and a plurality of rotation await times to arrange the second head from positions of a plurality of data sectors that correspond to the plurality of commands stored in the second queue, respectively, to positions of a plurality of different data sectors that correspond to a plurality of different commands, respectively, of the plurality of commands stored in the second queue, and
the second access costs include a plurality of seek times and a plurality of rotation await times to arrange the second head from the current position of the data sector of the second head to positions of the plurality of data sectors that correspond to the plurality of commands stored in the second queue, respectively.

9. A magnetic disk device, comprising:
a first disk;
a second disk;
a first head writing data to the first disk and reading data from the first disk;
a second head writing data to the second disk and reading data from the second disk;
a first actuator comprising the first head;
a second actuator comprising the second head;
a first arithmetic unit executing a first reordering process of a command stored in a first queue corresponding to the first actuator; and
a second arithmetic unit executing a second reordering process of a command stored in a second queue corresponding to the second actuator,
the first arithmetic unit executing the second reordering process,
the second arithmetic unit executing the first reordering process, wherein
based on a first command and a second command stored in the second queue, the first arithmetic unit calculates a first access cost equivalent to a time to arrange the second head from a position of a first data sector specified by the first command to a position of a second data sector specified by the second command, and transfers the first access cost and the second access cost to the second arithmetic unit, and
the second arithmetic unit stores the first command and the second command in the second queue, calculates a third access cost equivalent to a time to arrange the second head from a position of a fourth data sector to the position of the first data sector, and a fourth access cost equivalent to a time to arrange the second head from the position of the fourth data sector to the position of the second data sector, calculates a fifth access cost obtained by adding the first access cost and the third access cost and a sixth access cost obtained by adding the second access cost and the fourth access cost, and subsequently processes a command corresponding to a smallest access cost, of the fifth access cost and th

Assignees

• Toshiba Kk
• Toshiba Electronic Devices & Storage Corp

Inventors

• Sudo Daisuke

Classifications

• G11B5/5578 Primary

  Multiple actuators addressing the same disk, e.g. to improve data rate or access rate · CPC title

• G06F3/0676 Primary

  Magnetic disk device · CPC title

• G11B5/012

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

• G06F3/0611

  in relation to response time · CPC title

• G06F3/0614

  Improving the reliability of storage systems · CPC title