Serpentine seeks during data storage device idle periods

Patent metadata

Field	Value
Publication number	US-9852754-B1
Application number	US-201615281770-A
Country	US
Kind code	B1
Filing date	Sep 30, 2016
Priority date	Aug 9, 2016
Publication date	Dec 26, 2017
Grant date	Dec 26, 2017

Abstract

Apparatus and method for managing a data storage device during extended idle conditions of the data storage device in which host access commands are not being received or serviced. In some embodiments, upon detection of an idle condition, a control circuit identifies a selected data transducer of the data storage device and a corresponding initial radial position of the data transducer with respect to an associated rotatable data recording surface. The control circuit performs a serpentine seek operation during the idle condition to gradually advance the selected data transducer in a selected radial direction across the data recording surface beginning at the initial radial position and ending at a final radial position. The serpentine seek operation prevents the transducer from being maintained in a stationary position during the idle condition, reducing the likelihood of damage through thermal asperity contact events, lubrication disturb, wear, etc.

First claim

What is claimed is:

1. A method comprising:
detecting an idle condition for a data storage device comprising passage of a selected, uninterrupted amount of time since execution of a most recently received host access command by the data storage device;
identifying a selected data transducer of the data storage device and a corresponding initial radial position of the data transducer with respect to an associated rotatable data recording surface of the data storage device; and
performing a serpentine seek operation during the idle condition to gradually advance the selected data transducer in a selected radial direction across the data recording surface beginning at the initial radial position and ending at a final radial position, the data recording surface rotating at least 100 times while the data transducer is moving in the selected radial direction during the serpentine seek operation, the serpentine seek operation comprising a continuous velocity controlled seek of the data transducer during which the data transducer is accelerated away from the initial radial position, maintained at a maximum velocity, and decelerated to the final radial position.

2. The method of claim 1 , wherein the maximum velocity is less than 5% of a maximum velocity used by the data storage device during seeks carried out to service host access commands.

3. The method of claim 1 , further comprising a subsequent step of exiting the idle condition responsive to receipt of a host access command from the host device, and moving the data transducer to a destination track to service the host access command.

4. The method of claim 1 , wherein the initial radial position comprises a selected data track to which user data was written or from which user data was read using the data transducer during execution of the most recently received host access command, and the serpentine seek operation begins at the selected data track and ends at a destination track on the rotatable data recording surface.

5. The method of claim 1 , further comprising dividing the rotatable data recording surface into at least a first zone and a second zone, each of the first and second zones comprising a plurality of data tracks, determining the initial radial position is in a selected one of the first or second zones, and providing the selected radial direction to advance the data transducer toward the remaining one of the first or second zones.

6. The method of claim 1 , wherein the data transducer is a first data transducer and the data recording surface is a first data recording surface, the data storage device comprises a second data transducer adjacent a second data recording surface and nominally aligned with the first data transducer, and wherein the method further comprises, at the conclusion of the serpentine seek operation, performing a head switch operation to switch from the first data transducer to the second data transducer while maintaining the first data transducer at the final radial position, using the location of the second data transducer adjacent the second data recording surface as a second initial radial position, and performing a second serpentine seek operation to advance the second data transducer from the second initial radial position to a second final radial position on the second data recording surface in a second radial direction opposite the selected radial direction.

7. The method of claim 1 , wherein the rotatable data recording surface has a midpoint comprising a radial position that is nominally halfway between an innermost extent of the data recording surface and an outermost extent of the data recording surface, the initial radial position is on a first side of the midpoint, and the final radial position in on an opposing second side of the midpoint.

8. The method of claim 1 , wherein the serpentine seek operation requires at least one full second to transition the selected data transducer from the initial radial position to the final radial position.

9. A data storage device comprising:
a rotatable data recording surface divided into at least first and second concentric zones, the first zone adjacent an outermost diameter (OD) of the data recording surface and the second zone adjacent an innermost diameter (ID) of the data recording surface;
a data transducer configured to be positioned adjacent data tracks within each of the first and second zones to write data thereto and read data therefrom; and
a control circuit configured to detect an idle condition passage of a selected, uninterrupted amount of time since execution of a most recently received host access command by the data storage device, identify an initial radial position of the data transducer including a selected one of the first or second zones adjacent which the data transducer is disposed, and to perform a serpentine seek operation during the idle condition to gradually advance the data transducer from the initial radial position to a final radial position located in the remaining one of the first or second zones, the serpentine seek operation requiring at least one full second of elapsed time during which the transducer is moved away from the initial radial position and toward the final radial position, the serpentine seek operation comprising a succession of relatively short seeks each moving the data transducer from a different initial data track to different destination data track on the data recording surface between the initial radial position and the final radial position, the discrete serpentine seek operation including a relatively short dwell time on each of the different destination data tracks between successive pairs of the relatively short seeks so that the data transducer remains on each of the different destination tracks less than a full revolution of the data recording surface.

10. The data storage device of claim 9 , wherein the data recording surface rotates at least 100 times while the data transducer is moving in the selected radial direction during the serpentine seek operation.

11. The data storage device of claim 9 , wherein the data transducer reads servo data from spaced apart servo fields on each of the destination tracks and does not read user data from any user data sectors between adjacent pairs of the servo fields on each of the destination tracks.

12. The data storage device of claim 9 , wherein the initial radial position comprises a selected data track to which user data was written or from which user data was read using the data transducer during execution of the most recently received host access command, and the serpentine seek operation begins at the selected data track and ends at a destination track on the rotatable data recording surface.

13. The data storage device of claim 9 , wherein the data transducer is a first data transducer and the data recording surface is a first data recording surface, the data storage device further comprising a second data transducer adjacent a second data recording surface and nominally aligned with the first data transducer, and wherein the control circuit is further configured to, at the conclusion of the serpentine seek operation, perform a head switch operation to switch from the first data transducer to the second data transducer while maintaining the first data transducer at the final radial position, use the location of the second data transducer adjacent the second data recording surface as a second initial radial position, and perform a second serpentine seek operation to advance the second data transducer from the second initial radial position to a second final radial position on the second data recording surface in a second radial direction

Assignees

• Seagate Technology Llc

Inventors

• Martin Richard E
• Kataria Abhay T
• Purani Dipeshkumar J
• Herr Richard A
• Le Alexander T
• Sequeira Sandeep D
• Yang Lingzhi
• Shan Ximin
• Al Saif Salman

Classifications

• G11B5/5547 Primary

  "Seek" control and circuits therefor (G11B5/5556 takes precedence) · CPC title

• G11B5/40

  Protective measures on heads, e.g. against excessive temperature  (G11B5/31 takes precedence; protection against wear G11B5/255  {; protective structure of the head: see under structures, e.g. G11B5/3106}) · CPC title