Soft error recovery system and method

• US 5,530,705 A
• Filed: 02/08/1995
• Issued: 06/25/1996
• Est. Priority Date: 02/08/1995
• Status: Expired due to Term

• Current Assignee: HGST Netherlands B.V. (Western Digital Corporation)
• Original Assignee: International Business Machines Corporation
• Inventors: Malone, Daniel J. Sr.
• Primary Examiner(s): Beausoliel, Jr., Robert W.
• Assistant Examiner(s): Chung, Phung M.
• Application Number:
  US08/385,283
• Time in Patent Office: 503 Days
• Field of Search: 371/5.1, 371/47.1, 371/5.5, 371/21.4, 371/21.1, 371/15.1, 360/62, 360/26, 360/36, 360/38, 360/47, 360/53, 365/201
• US Class Current: 714/704
• CPC Class Codes: G11B 20/1816 Testing
• CPC Class Codes: G11B 27/36 Monitoring, i.e. supervising the progress of recording or reproducing for digital recording G11B20/00 and s.gr.; for monitoring, testing or measuring of TV recorders of the type covered by H04N5/76 and subgroups, see H04N17/06

Abstract

A method for reducing errors in data read from a disk drive comprises the steps of: determining errors in data read from a transducer in the disk drive; correcting the errors in data through the use of error correction circuitry; maintaining a metric of the errors in data that are read from the transducer; and when the metric reaches a threshold value, applying a toggle procedure to the transducer in an attempt to improve the transducer'"'"'s performance. The method further contemplates periodically applying a toggle procedure to the transducer in an attempt to reduce the errors in data, in addition to the application of a toggle procedure when the threshold value is reached.

Claims

1. A method for reducing errors in data read from a disk drive, said method comprising the steps of:

a. determining errors in data read from a transducer in said disk drive;

b. correcting said errors in data;

c. maintaining a metric of said errors in data read from said transducer which are corrected;

d. when said metric reaches a threshold value that is less than a metric which indicates an uncorrectable error state, applying a toggle procedure to said transducer in an attempt to reduce said errors in data;

e. moving said transducer to a disk area so as to enable a writing of data without impacting other usable data; and

f. applying at least a write excitation to said transducer.

2. The method as recited in claim 1, wherein said transducer is a thin film inductive transducer or a ferrite transducer and said

write excitation is followed by a read of data written by said write excitation.

3. The method as recited in claim 1, wherein said transducer is a magnetoresistive transducer having an applied bias current, said magnetoresistive transducer having separate read and write elements,

wherein said write excitation is applied to said write element of said transducer.

4. The method as recited in claim 1, comprising a further substep b1:

1. periodically applying a toggle procedure to said transducer in an attempt to reduce said errors in data.

5. The method as recited in claim 1, wherein said toggle procedure is applied to all transducers in said disk drive.

6. A method for reducing errors in data read from a disk drive by a magnetoresistive transducer having an applied bias current, said magnetoresistive transducer having separate read and write elements, said method comprising the steps of;

a. determining errors in data read from a transducer in said disk drive;

b. correcting said errors in data;

c. maintaining a metric of said errors in data read from said transducer which are corrected;

d . when said metric reaches a threshold value that is less than a metric which indicates an uncorrectable error state, applying a toggle procedure to said transducer in an attempt to reduce said errors in data, said toggle procedure altering said applied bias current to said transducer.

7. A system for reducing errors in data read from a disk drive, said system comprising:

error detection means for determining errors in data read from a transducer in said disk drive;

error correction means coupled to said error detection means for correcting said errors in data; and

processor means for maintaining a metric of said errors in data read from said transducer that are corrected and when said metric reaches a threshold value that is less than a metric which indicates an uncorrectable error state, causing a toggle procedure to be applied to said transducer in an attempt to reduce said errors in data, said processor means additionally, periodically causing said toggle procedure to be applied to said transducer in an attempt to reduce said errors in data.

8. The system as recited in claim 7, wherein said processor means applies said toggle procedure to all transducers in said disk drive.