IP Library Granted Patent US 8,755,136
Granted Patent B1
US 8,755,136 · App. 13/450,290 · Granted Jun 17, 2014

Systems and methods for storage device read/write head malfunction detection

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Quick Facts
Patent No.
US 8,755,136
App. No.
13/450,290
Granted
Jun 17, 2014
Kind
B1
Abstract

In various embodiments, systems and methods to detect signal irregularity caused by defects in the read/write head element are disclosed. In some embodiments, an exemplary system comprises a memory and a processor. The processor is coupled to the memory and is configured to implement a filter module and a detector module. The filter module is configured to generate a test waveform based on data read from a medium by a storage device head to be tested. The detector module is configured to generate a signal quality value based on a property of at least a portion of the test waveform, compare the signal quality value to an event threshold, and generate an event indicator based on the comparison, the event indicator indicating possible instability of the storage device head.

Claims (90)

1. A system comprising:

a memory,

a processor, coupled with the memory, the processor configured to implement:

a filter module configured to generate a test waveform based on data read from a medium by a storage device head to be tested;

a detector module configured to:

generate a signal quality value based on a property of at least a portion of the test waveform,

compare the signal quality value to an event threshold, and

generate an event indicator based on the comparison, the event indicator indicating possible instability of the storage device head; and

an accumulator module configured to aggregate the event indicator with other event indicators to generate an aggregate indicator.

2. The system of claim 1 , wherein the accumulator module is further configured to compare the aggregate indicator to an instability threshold.

3. The system of claim 2 , wherein the processor is further to implement a notification module configured to provide a notification regarding instability of the storage device head based on the comparison of the aggregate indicator to the instability threshold.

4. The system of claim 2 , wherein the processor is further configured to change a bias voltage across the storage device head based on the comparison of the aggregate indicator to the instability threshold.

5. The system of claim 1 , wherein the detector module is further configured to generate the signal quality value based on the property of the at least the portion of the test waveform by averaging over time the property of the at least the portion of the test waveform.

6. The system of claim 1 , wherein the property of the at least the portion of the test waveform comprises amplitude.

7. The system of claim 1 , the data comprises a predetermined pattern of the data written on the medium.

8. The system of claim 7 , wherein the predetermined pattern comprises data written to the medium at a 2T frequency.

9. The system of claim 1 , wherein the detector module is further configured to detect changes of consistency within the at least the portion of the test waveform.

10. The system of claim 1 , further comprising a storage device controller configured to stress the storage device head to be tested during writing of a predetermined pattern to the medium or to stress the storage device head to be tested during a read-back of the data from the medium.

11. A method comprising:

reading, by a storage device head to be tested, data from a medium;

generating a test waveform based on the data read from the medium;

determining a signal quality value based on a property of at least a portion of the test waveform;

comparing the signal quality value to an event threshold;

generating an event indicator based on the comparison, the event indicator indicating possible instability of the storage device head; and

aggregating the event indicator with other event indicators to generate an aggregate indicator.

12. The method of claim 11 , further comprising comparing the aggregate indicator to an instability threshold.

13. The method of claim 12 , further comprising providing a notification regarding instability of the storage device head based on the comparison of the aggregate indicator to the instability threshold.

14. The method of claim 12 , further comprising changing a bias voltage across the storage device head based on the comparison of the aggregate indicator to the instability threshold.

15. The method of claim 11 , wherein generating the signal quality value based on the property of the at least the portion of the test waveform comprises averaging over time the property of the at least the portion of the test waveform.

16. The method of claim 11 , wherein determining the signal quality value is based on the property of the at least the portion of the test waveform comprises averaging amplitudes of one or more sections of the test waveform.

17. The method of claim 11 , wherein the data comprises a predetermined pattern written to the medium.

18. The method of claim 17 , wherein the predetermined pattern comprises the data written to the medium at a 2T frequency.

19. The method of claim 11 , further comprising receiving a predetermined window threshold and identifying the test waveform as a subsection of a larger waveform associated with the data read from the medium based on the predetermined window threshold.

20. The method of claim 11 , wherein comparing the signal quality value to the event threshold comprises detecting changes of consistency within the at least the portion of the test waveform.

21. The method of claim 11 , further comprising stressing the storage device head at the time of or before reading the data from the medium.

22. A system comprising:

a storage device head to be tested configured to read data from a medium;

a means for generating a test waveform based on the data read from the medium;

a means for generating a signal quality value based on a property of at least a portion of the test waveform;

a means for comparing the signal quality value to an event threshold;

a means for generating an event indicator based on the comparison, the event indicator indicating possible instability of the storage device head;

a means for storing the event indicator, and

a means for aggregating the event indicator with other event indicators to generate an aggregate indicator.

23. A system comprising:

a memory,

a processor, coupled with the memory, the processor configured to implement:

a filter module configured to generate a test waveform based on data read from a medium by a storage device head to be tested;

a detector module configured to:

generate a signal quality value based on a property of at least a portion of the test waveform by averaging over time the property of the at least the portion of the test waveform,

compare the signal quality value to an event threshold,

 generate an event indicator based on the comparison, the event indicator indicating possible instability of the storage device head, and

generate the signal quality value based on the property of the at least the portion of the test waveform by averaging over time the property of the at least the portion of the test waveform.

24. The system of claim 23 , wherein the processor is further to implement an accumulator module configured to aggregate the event indicator with other event indicators to generate an aggregate indicator.

25. The system of claim 24 , wherein the accumulator module is further configured to compare the aggregate indicator to an instability threshold.

26. The system of claim 25 , wherein the processor is further to implement a notification module configured to provide a notification regarding instability of the storage device head based on the comparison of the aggregate indicator to the instability threshold.

27. The system of claim 25 , wherein the processor is further configured to change a bias voltage across the storage device head based on the comparison of the aggregate indicator to the instability threshold.

28. A method comprising:

reading, by a storage device head to be tested, data from a medium;

generating a test waveform based on the data read from the medium;

determining a signal quality value based on a property of at least a portion of the test waveform by at least averaging over time the property of the at least the portion of the test waveform;

comparing the signal quality value to an event threshold; and

generating an event indicator based on the comparison, the event indicator indicating possible instability of the storage device head.

29. The method of claim 28 , further comprising aggregating the event indicator with other event indicators to generate an aggregate indicator.

30. The method of claim 29 , further comprising comparing the aggregate indicator to an instability threshold.

31. The method of claim 30 , further comprising providing a notification regarding instability of the storage device head based on the comparison of the aggregate indicator to the instability threshold.

32. The method of claim 30 , further comprising changing a bias voltage across the storage device head based on the comparison of the aggregate indicator to the instability threshold.

33. A system comprising:

a memory,

a processor, coupled with the memory, the processor configured to implement:

a filter module configured to receive a predetermined window threshold and identify a test waveform as a subsection of a larger waveform associated with data read from a medium by a storage device head to be tested based on the predetermined window threshold; and

a detector module configured to:

generate a signal quality value based on a property of at least a portion of the test waveform,

compare the signal quality value to an event threshold, and

generate an event indicator based on the comparison, the event indicator indicating possible instability of the storage device head.

34. The system of claim 33 , wherein the processor is further to implement an accumulator module configured to aggregate the event indicator with other event indicators to generate an aggregate indicator.

35. The system of claim 34 , wherein the accumulator module is further configured to compare the aggregate indicator to an instability threshold.

36. The system of claim 35 , wherein the processor is further to implement a notification module configured to provide a notification regarding instability of the storage device head based on the comparison of the aggregate indicator to the instability threshold.

37. The system of claim 35 , wherein the processor is further configured to change a bias voltage across the storage device head based on the comparison of the aggregate indicator to the instability threshold.

38. The system of claim 33 , wherein the detector module is further configured to generate the signal quality value based on the property of the at least the portion of the test waveform by averaging over time the property of the at least the portion of the test waveform.

39. A method comprising:

reading, by a storage device head to be tested, data from a medium;

receiving a predetermined window threshold and identifying a test waveform as a subsection of a larger waveform associated with the data read from the medium based on the predetermined window threshold;

determining a signal quality value based on a property of at least a portion of the test waveform;

comparing the signal quality value to an event threshold; and

generating an event indicator based on the comparison, the event indicator indicating possible instability of the storage device head.

40. The method of claim 39 , further comprising aggregating the event indicator with other event indicators to generate an aggregate indicator.

41. The method of claim 40 , further comprising comparing the aggregate indicator to an instability threshold.

42. The method of claim 41 , further comprising providing a notification regarding instability of the storage device head based on the comparison of the aggregate indicator to the instability threshold.

43. The method of claim 41 , further comprising changing a bias voltage across the storage device head based on the comparison of the aggregate indicator to the instability threshold.

44. The method of claim 39 , wherein generating the signal quality value based on the property of the at least the portion of the test waveform comprises averaging over time the property of the at least the portion of the test waveform.

Assignments (8)
PATENT COLLATERAL AGREEMENT - DDTL LOAN AGREEMENT Recorded Aug 21, 2023
From: WESTERN DIGITAL TECHNOLOGIES, INC.
To: JPMORGAN CHASE BANK, N.A.
Reel/Frame 067045/0156 →
PATENT COLLATERAL AGREEMENT - A&R LOAN AGREEMENT Recorded Aug 21, 2023
From: WESTERN DIGITAL TECHNOLOGIES, INC.
To: JPMORGAN CHASE BANK, N.A.
Reel/Frame 064715/0001 →
RELEASE OF SECURITY INTEREST AT REEL 038744 FRAME 0481 Recorded Feb 8, 2022
From: JPMORGAN CHASE BANK, N.A.
To: WESTERN DIGITAL TECHNOLOGIES, INC.
Reel/Frame 058982/0556 →
RELEASE OF SECURITY INTEREST Recorded Mar 5, 2018
From: U.S. BANK NATIONAL ASSOCIATION, AS COLLATERAL AGENT
To: WESTERN DIGITAL TECHNOLOGIES, INC.
Reel/Frame 045501/0714 →
SECURITY AGREEMENT Recorded May 17, 2016
From: WESTERN DIGITAL TECHNOLOGIES, INC.
To: JPMORGAN CHASE BANK, N.A., AS COLLATERAL AGENT
Reel/Frame 038744/0481 →
SECURITY AGREEMENT Recorded May 17, 2016
From: WESTERN DIGITAL TECHNOLOGIES, INC.
To: U.S. BANK NATIONAL ASSOCIATION, AS COLLATERAL AGENT
Reel/Frame 038744/0281 →
SECURITY AGREEMENT Recorded May 17, 2016
From: WESTERN DIGITAL TECHNOLOGIES, INC.
To: JPMORGAN CHASE BANK, N.A., AS COLLATERAL AGENT
Reel/Frame 038722/0229 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Apr 18, 2012
From: NG, KIAN WAI; JUNG, KAMERON K.; CHEN, JINGHUAN
To: WESTERN DIGITAL TECHNOLOGIES, INC.
Reel/Frame 028068/0619 →