Directional write retry for shingled disk drive application
AssigneeWestern Digital Technologies, Inc.
InventorsEric J. Champion, James N. Malina
Life of this patent
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Abstract
Embodiments described herein include systems and methods for correcting for errors caused by disturbances to disk drives, such as disturbances due to shocks or vibrations incident on the drive. For example, systems and methods described herein advantageously correct for corruption to current data as well as previously written. Data may be rewritten in the current track that was being written to when the disturbance occurred, and may also be rewritten to one or more nearby previously written tracks, such as one or more adjacent tracks. According to some aspects, the direction of head deviation is used to select the appropriate corrective action.
Claims18
A method of performing error correction in a shingled disk drive, comprising:
- writing data to a disk in a first radial direction using a head, the head moving according to a predetermined trajectory;
- and
- by a controller of the disk drive:
- receiving a signal indicating that the head has deviated from its predetermined trajectory while writing a current data sector to a first track of the disk;
- in response to the signal, determining a direction in which the head deviated from the predetermined trajectory;
- and
- when it is determined that the head deviated in the first radial direction, rewriting the current data sector to a second track located adjacent to the first track in the first radial direction;
- and
- when it is determined that the head deviated in a second radial direction substantially opposite to the first radial direction:
- rewriting one or more corrupted data sectors from a third track to the first track, the third track located adjacent to the first track in the second radial direction;
- and
- rewriting one or more data sectors from the first track to the second track.
A shingled disk drive, comprising:
- a rotatable disk;
- a head configured to write data to the disk in a first radial direction and to move according to a predetermined trajectory;
- and
- a controller configured to:
- (a) receive a signal indicating that the head has deviated from its predetermined trajectory while writing a current data sector to a first track of the disk;
- (b) determine, in response to the signal, a direction in which the head deviated from the predetermined trajectory;
- (c) when it is determined that the head deviated in the first radial direction, rewriting the current data sector to a second track located adjacent to the first track in the first radial direction;
- and
- (d) when it is determined that the head deviated in a second radial direction substantially opposite to the first radial direction:
- rewriting one or more corrupted data sectors from a third track to the first track, the third track located adjacent to the first track in the second radial direction;
- and
- rewriting one or more data sectors from the first track to the second track.
Dependencies are inferred from the claim text.