Multi-speed data storage device with media cache for high speed writes

Patent metadata

Field	Value
Publication number	US-10318173-B2
Application number	US-201615281857-A
Country	US
Kind code	B2
Filing date	Sep 30, 2016
Priority date	Sep 30, 2016
Publication date	Jun 11, 2019
Grant date	Jun 11, 2019

Abstract

Apparatus and method for managing data transfers in a data storage device with rotational media that can be rotated at different speeds. In some embodiments, a non-volatile main memory is formed on a rotatable medium accessed by a moveable data transducer. A media cache provides a non-volatile data storage area. A control circuit directs writes to the main memory as the medium is rotated at a first speed and directs reads from the main memory as the medium is rotated at a higher, second speed. Writes during the rotation of the medium at the second speed are directed to the media cache instead of to the main memory so that no data are written to the main memory at the second speed. The media cache may also be located on the medium or may be formed from solid-state semiconductor memory.

First claim

What is claimed is:

1. An apparatus comprising:
a rotatable data recording medium supported by a spindle motor to provide a main memory as a non-volatile data storage area, the spindle motor configured to provide constant angular velocity (CAV) rotation of the medium at different nominally constant speeds;
a read/write data transducer configured to write data to and read data from the main memory;
a media cache comprising a non-volatile data storage area; and
a control circuit configured to direct the rotation of the data recording medium at a first speed during write operations by the data transducer to write a first set of user data blocks to the main memory responsive to a first set of host access commands received from a host device while the data recording medium is rotated at the first speed, to direct the rotation of the data recording medium at a second speed greater than the first speed during read operations by the data transducer to read a second set of user data blocks from the main memory responsive to a second set of host access commands received from the host device, the control circuit further configured to direct the writing of a third set of user data blocks to the media cache instead of to the main memory responsive to a third set of host access commands received from the host device while the data recording medium is rotated at the second speed so that no user data blocks are written to the main memory at the second speed.

2. The apparatus of claim 1 , wherein the main memory comprises a first plurality of data tracks at a first radial location on the medium, and the media cache comprises a different, second plurality of data tracks at a different, second radial location on the medium.

3. The apparatus of claim 2 , wherein the first plurality of data tracks each have a first radial track pitch, and the second plurality of data tracks each have a second radial track pitch greater than the first radial track pitch to compensate for non-repeatable runout (NRRO) errors induced during the rotation of the medium at the second speed.

4. The apparatus of claim 2 , wherein the first plurality of data tracks have a first radial track density, and the second plurality of data tracks have a second radial track density less than the first radial track density.

5. The apparatus of claim 2 , wherein the user data are written to the first plurality of data tracks at a first data frequency, and the user data are written to the second plurality of data tracks at a lower second data frequency.

6. The apparatus of claim 1 , wherein the media cache comprises solid-state non-volatile semiconductor memory.

7. The apparatus of claim 1 , wherein the first speed is nominally 75% of the second speed.

8. The apparatus of claim 1 , wherein the control circuit transitions from the first speed to the second speed responsive to a mode select value supplied by a multi-device controller circuit in a multi-storage device environment.

9. The apparatus of claim 1 , wherein the first speed is nominally 5400 revolutions per minute (rpm) and the second speed is nominally 7200 rpm.

10. The apparatus of claim 1 , wherein the control circuit is further configured to subsequently transfer the user data written to the media cache at the second speed to the main memory while the medium rotates at the first speed.

11. A method comprising:
providing a data storage device having a media cache, a data storage medium rotatable at different selectable constant angular velocity (CAV) speeds and having a first plurality of data tracks to define a main memory, and a data read/write transducer configured to access the first plurality of data tracks in the main memory;
using the transducer to write a first set of user data blocks to the first plurality of data tracks in the main memory responsive to a first set of host access commands received from a host device during rotation of the medium at a first speed and to read a second set of user data blocks from the first plurality of data tracks in the main memory responsive to a second set of host access commands received from the host device, the medium accelerated to a second speed greater than the first speed prior to the reading of the second set of user data blocks responsive to the receipt of the second set of host access commands; and
writing a third set of user data blocks to the media cache instead of to the main memory responsive to a third set of host access commands received from the host device during rotation of the medium at the second speed so that no user data blocks are written to the main memory while the medium is rotated at the second speed; and
subsequently transferring the third set of user data blocks from the media cache to the main memory responsive to a deceleration of the medium from the second speed to the first speed.

12. The method of claim 11 , wherein the media cache is disposed on the medium as a second plurality of data tracks.

13. The method of claim 12 , wherein the second plurality of data tracks in the media cache have at least a selected one of a radial track width or a radial track pitch as compared to the first plurality of data tracks in the main memory.

14. The method of claim 12 , wherein the second plurality of data tracks are written at a lower frequency than the first plurality of data tracks in the main memory.

15. The method of claim 11 , wherein the media cache comprises solid-state non-volatile semiconductor memory.

16. The method of claim 11 , further comprising temporarily storing the third set of user data blocks in a buffer memory, providing a write complete status to the host device responsive to the third set of access commands, and transferring the third set of user data blocks from the buffer memory to the media cache after the write complete status is provided to the host device.

17. The method of claim 11 , further comprising rotating the medium at both the first and second speeds using a common source of power comprising a selected one of a battery or alternating current (AC) power.

18. A hard disc drive (HDD), comprising:
a rotatable data recording medium supported by a spindle motor to provide a main memory as a non-volatile data storage area comprising a first set of concentric data tracks at a first radial pitch and a media cache as a non-volatile data storage area comprising a second set of concentric data tracks at a second radial pitch greater than the first radial pitch;
a spindle motor control circuit coupled to the spindle motor and configured to rotate the medium at a first speed and a second speed greater than the first speed;
a read/write data transducer configured to write data to and read data from the main memory and the media cache; and
a controller circuit configured to direct the writing of a first set of user data blocks by the transducer to the main memory responsive to a first set of write commands received from a host device during the rotation of the medium at the first speed and to direct the writing of a second set of user data blocks by the transducer to the media cache responsive to a second set of write commands received from the host device during the rotation of the medium at the second speed.

19. The HDD of claim 18 , wherein the controller circuit is further configured to, responsive to receipt of a first set of read commands from the host, direct the spindle motor control circuit to accelerate the medium from the first speed to the second speed and to direct the transducer to read a third set of user data blocks from a selected one o

Assignees

• Seagate Technology Llc

Inventors

• Ooi Kian Keong
• Kan Utt Heng
• Bi Qiang
• Tan Chi Sern

Classifications

• G06F3/0656

  Data buffering arrangements · CPC title

• G06F3/068

  Hybrid storage device · CPC title

• G06F3/0611 Primary

  in relation to response time · CPC title

• G06F2212/222

  Non-volatile memory · CPC title

• G06F2212/224

  Disk storage · CPC title