Efficient scheduling of data storage disc input/output

Patent metadata

Field	Value
Publication number	US-12182444-B2
Application number	US-202217703303-A
Country	US
Kind code	B2
Filing date	Mar 24, 2022
Priority date	Mar 24, 2022
Publication date	Dec 31, 2024
Grant date	Dec 31, 2024

Abstract

A method includes creating a table with a plurality of cells indicative of intersections of tracks and wedges on a data storage disc surface. The method also includes storing disc pending command information for different disc pending commands in corresponding different cells of the plurality of cells according to locations for the different disc pending commands on the data storage disc surface. The method further includes searching the table for one or more next disc pending commands of the different disc pending commands to schedule for execution.

First claim

What is claimed is:

1. A method comprising:
creating a table with a plurality of cells indicative of intersections of tracks and wedges on a data storage disc surface;
storing disc pending command information for different disc pending commands in corresponding different cells of the plurality of cells according to locations for the different disc pending commands on the data storage disc surface;
linking at least one of rows or columns that are occupied by command extents of the disc pending command information;
searching the table for one or more next disc pending commands of the different disc pending commands to schedule for execution; and
accelerating the search using the linked at least one of rows or columns,
wherein accelerating the search comprises skipping at least one of the rows or the columns that are not occupied by any command extents.

2. The method of claim 1 , and wherein searching the table for one or more next disc pending commands of the different disc pending commands to schedule for execution comprises:
identifying a head location cell of the plurality of cells corresponding to a current location of a head over the data storage disc surface;
generating a first search window that includes first cells of the plurality of cells that are within a first column of the table at a first predetermined distance from the head location cell;
determining whether any of the disc pending command information is within the first search window; and
when none of the disc pending command information is within the first search window or when any of the disc pending command information in the first search window is not applicable for one or more predetermined search conditions, generating a second search window that includes second cells of the plurality of cells that are within a second column of the table at a second predetermined distance from the head location cell, the second predetermined distance being greater than the first predetermined distance, and the second cells being greater in number than the first cells.

3. The method of claim 1 , and wherein searching the table for one or more next disc pending commands of the different disc pending commands to schedule for execution comprises:
identifying a head location cell of the plurality of cells corresponding to a current location of a head over the data storage disc surface;
generating a first search window that includes first cells of the plurality of cells that are within a first row of the table at a first predetermined distance from the head location cell;
determining whether any of the disc pending command information is within the first search window; and
when none of the disc pending command information is within the first search window or when any of the disc pending command information in the first search window is not applicable for one or more predetermined search conditions, generating a second search window that includes second cells of the plurality of cells that are within a second row of the table at a second predetermined distance from the head location cell, the second predetermined distance being greater than the first predetermined distance, and the second cells being greater in number than the first cells.

4. The method of claim 1 , wherein starting extents of the command extents are linked in wedge or cylinder order.

5. The method of claim 1 , and further comprising deleting starting extents for any disc pending command from both the disc pending command table and existing links of the linked at least one of rows or columns when the disc pending command is completed.

6. The method of claim 5 , and further comprising adding starting extents for new disc pending commands to be scheduled to the disc pending command table and inserting the starting extents for the new disc pending commands into existing links of the linked at least one of rows or columns.

7. A data storage system comprising:
at least one data storage disc comprising at least one data storage surface;
at least one head configured to interact with the at least one data storage surface;
a memory comprising a table with a plurality of cells indicative of intersections of tracks and wedges on the at least one data storage surface; and
a controller, communicatively coupled to the at least one head and the memory, the controller configured to:
store disc pending command information for different disc pending commands in corresponding different cells of the plurality of cells according to locations for the different disc pending commands on the at least one data storage surface;
link at least one of rows or columns that are occupied by command extents of the disc pending command information;
search the table for one or more next disc pending commands of the different disc pending commands to schedule for execution by the at least one head;
accelerate the search using the linked at least one of rows or columns; and
accelerate the search by skipping at least one of the rows or the columns that are not occupied by any command extents.

8. The data storage system of claim 7 , and wherein the controller is further configured to search the table for the one or more next disc pending commands of the different disc pending commands to schedule for execution by the at least one head by:
identifying a head location cell of the plurality of cells corresponding to a current location of the at least one head over the at least one data storage surface;
generating a first search window that includes first cells of the plurality of cells that are within a first column of the table at a first predetermined distance from the head location cell;
determining whether any of the disc pending command information is within the first search window; and
when none of the disc pending command information is within the first search window or when any of the disc pending command information in the first search window is not applicable for one or more predetermined search conditions, generating a second search window that includes second cells of the plurality of cells that are within a second column of the table at a second predetermined distance from the head location cell, the second predetermined distance being greater than the first predetermined distance, and the second cells being greater in number than the first cells.

9. The data storage system of claim 7 , and wherein the controller is further configured to search the table for the one or more next disc pending commands of the different disc pending commands to schedule for execution by the at least one head by:
identifying a head location cell of the plurality of cells corresponding to a current location of the at least one head over the at least one data storage surface;
generating a first search window that includes first cells of the plurality of cells that are within a first row of the table at a first predetermined distance from the head location cell;
determining whether any of the disc pending command information is within the first search window; and
when none of the disc pending command information is within the first search window or when any of the disc pending command information in the first search window is not applicable for one or more predetermined search conditions, generating a second search window that includes second cells of the plurality of cells that are within a second row of the table at a second predetermined distance from the head location cell, the second predetermined distance being greater than the first predetermined distance, and the second cells being greater in number than the first cells.

10. The data storage device of claim 7 , wherein the controller is further configured to link s

Assignees

• Seagate Technology Llc

Inventors

• Kulkarni Ajay Narayan
• Fnu Ronny
• Tiotantra Harry
• Gaertner Mark A

Classifications

• G06F3/0611

  in relation to response time · CPC title

• G06F3/0604

  Improving or facilitating administration, e.g. storage management · CPC title

• G06F3/0674

  Disk device · CPC title

• G06F3/0656

  Data buffering arrangements · CPC title

• G06F3/0659 Primary

  Command handling arrangements, e.g. command buffers, queues, command scheduling · CPC title