Method and apparatus that modifies seeks to remediate inter-actuator coupling in a storage drive

Patent metadata

Field	Value
Publication number	US-10192576-B1
Application number	US-201715831919-A
Country	US
Kind code	B1
Filing date	Dec 5, 2017
Priority date	Dec 5, 2017
Publication date	Jan 29, 2019
Grant date	Jan 29, 2019

Abstract

A faulty tracking condition affecting a first head driven by a first actuator of a hard disk drive is determined. The faulty tracking condition is caused by a second actuator of the hard disk drive that is moving while the first actuator is performing a tracking operation. Responsive to the determination of the faulty tracking condition, seek forces of the second actuator that cause the faulty tracking condition affecting the first head are reduced. A controller verifies that similar faulty tracking conditions are reduced with the first head in response to the reduction in seek forces.

First claim

What is claimed is:

1. A method, comprising:
determining a faulty tracking condition affecting a first head driven by a first actuator of a hard disk drive, the faulty tracking condition caused by a second actuator of the hard disk drive that is moving while the first actuator is performing a tracking operation:
responsive to the determination of the faulty tracking condition, reducing seek forces of the second actuator that cause the faulty tracking condition affecting the first head; and
verifying that similar faulty tracking conditions are reduced with the first head responsive to the reduction in seek forces.

2. The method of claim 1 , wherein verifying that similar faulty tracking conditions are reduced with the first head comprises an open-loop control procedure that involves:
returning to normal operation after reducing the seek forces; and
determining, in response to a trigger, whether the similar faulty tracking conditions are reduced.

3. The method of claim 2 , wherein the determining whether the similar faulty tracking condition occurs is further in response to an elapsed time since a previous similar determination occurred exceeds a time threshold.

4. The method of claim 1 , wherein verifying that similar faulty tracking conditions are reduced with the first head comprises a closed-loop control procedure that involves:
actively monitoring a test operation or normal operation after reducing the seek forces; and
determining, in response the active monitoring, whether the similar faulty tracking condition occurs.

5. The method of claim 4 , wherein the closed-loop control procedure further involves iteratively changing a remedial action that reduces the seek forces and determining whether the similar faulty tracking conditions are reduced in response to the change.

6. The method of claim 1 , wherein reducing seek forces of the second actuator applied to the first actuator comprises rescheduling operations of the second actuator to mitigate the faulty tracking condition, the rescheduling reducing long seeks of the second actuator.

7. The method of claim 1 , wherein reducing the seek forces comprises reducing one of an acceleration and deceleration of the second actuator during seeks by the second actuator.

8. The method of claim 1 , wherein reducing the seek forces comprises reducing both of an acceleration and deceleration of the second actuator during seeks by the second actuator.

9. The method of claim 1 , wherein the reduction of the seek forces is scaled based on at least one of a magnitude and a type of the faulty tracking condition.

10. The method of claim 1 , wherein the determining of the faulty tracking condition comprises determining that an excessive number of seeks of the first actuator past an expected position have occurred.

11. The method of claim 1 , wherein the determining of the faulty tracking condition comprises determining that an excessive number of off-track write faults have occurred.

12. The method of claim 1 , wherein the determining of the faulty tracking condition comprises determining that an excessive time spent in susceptible mode by the first head has occurred.

13. The method of claim 1 , wherein the determining of the faulty tracking condition comprises determining a weighted combination of number of off-track write faults, number of seeks of the first actuator past an expected position, and time spent in susceptible mode by the first head.

14. A data storage drive comprising:
interface circuitry coupled to first and second actuators that drive respective first and second heads that read one or more disks; and
a controller coupled to the interface circuitry and operable to:
determine a faulty tracking condition affecting the first head caused by the second actuator moving while the first actuator is performing a tracking operation:
responsive to the determination of the faulty tracking condition, reduce seek forces of the second actuator that cause the faulty tracking condition affecting the first head; and
verify that similar faulty tracking conditions are reduced with the first head responsive to the reduction in seek forces of a hard disk drive, the faulty tracking condition caused by a second actuator.

15. The data storage drive of claim 14 , wherein the determining of the faulty tracking condition comprises determining any combination of a number of off-track write faults, a number of seeks of the first actuator past an expected position, and a time spent in susceptible mode by the first head.

16. The data storage drive of claim 14 , wherein reduction of the seek forces comprises any combination of rescheduling operations of the second actuator to reduce long seeks, reducing an acceleration and of the second actuator during seeks, and reducing a deceleration of the second actuator during the seeks.

Assignees

• Seagate Technology Llc

Inventors

• Gaertner Mark Allen
• Kharisov Evgeny
• Wernow Josiah Natan

Classifications

• G06F3/0676

  Magnetic disk device · CPC title

• G11B5/5578

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

• G11B5/5547 Primary

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

• G11B5/54

  with provision for moving the head into or out of its operative position or across tracks · CPC title

• G11B5/4813

  Mounting or aligning of arm assemblies, e.g. actuator arm supported by bearings, multiple arm assemblies, arm stacks or multiple heads on single arm (G11B5/484 takes precedence) · CPC title