Write head offset for shingled magnetic recording (smr) disk drives

Patent metadata

Field	Value
Publication number	US-2016372143-A1
Application number	US-201514746744-A
Country	US
Kind code	A1
Filing date	Jun 22, 2015
Priority date	Jun 22, 2015
Publication date	Dec 22, 2016
Grant date	—

Abstract

Methods, systems, and apparatuses are described for provisioning storage devices. An example method includes determining a write status of an adjacent track that is adjacent to a target track of a shingled magnetic recording (SMR) disk drive. The method may further include determining an offset for a write head based on the write status of the adjacent track and positioning the write head according to the offset.

First claim

1 . A method for data storage, comprising:
determining a write status of an adjacent track that is adjacent to a target track of a shingled magnetic recording (SMR) disk drive; determining an offset for a write head based on the write status of the adjacent track, the offset comprising a physical repositioning of the write head; and positioning the write head according to the offset.

2 . The method of claim 1 , wherein determining the write status of the adjacent track further comprises:
determining the write status of the adjacent track from a track usage monitoring (TUM) table.

3 . The method of claim 1 , wherein positioning the write head further comprises:
shifting the write head according to the offset towards the adjacent track when the write status indicates the adjacent track is unused.

4 . The method of claim 1 , further comprising:
determining a track overlap between the adjacent track and the target track, wherein determining the offset is based at least in part on the track overlap.

5 . The method of claim 4 , wherein determining the offset further comprises:
determining half of a sum of the track overlap and two times an unadjusted on-cylinder limit (OCLIM).

6 . The method of claim 1 , wherein positioning the write head according to the offset further comprises:
positioning the write head by adding the offset to an unadjusted on-cylinder limit (OCLIM).

7 . The method of claim 1 , wherein the adjacent track is on an unshingled side of the target track.

8 . The method of claim 1 , wherein positioning the write head further comprises:
shifting a write center of a write head by the offset to an unshingled side of the target track, wherein the offset is equal to or less than an unadjusted on-cylinder limit (OCLIM).

9 . The method of claim 1 , wherein determining the offset further comprises:
setting the offset to zero when the adjacent track is on a shingled side of the target track.

10 . The method of claim 1 , further comprising:
receiving a write command to write data to the target track; writing to the target track using the write head positioned according to the offset; and updating a track usage monitoring (TUM) table based on the writing to the target track.

11 . An apparatus, comprising:
at least one processor; and memory coupled to the at least one processor, wherein the memory includes instructions that are executable by the at least one processor to:
determine a write status of an adjacent track that is adjacent to a target track of at least one data storage medium;
determine an offset for the write head based on the write status of the adjacent track, the offset comprising a physical repositioning of the write head; and
position the write head according to the offset.

12 . The apparatus of claim 11 , wherein the memory further includes instructions that are executable by the at least one processor to determine the write status of the adjacent track from a track usage monitoring (TUM) table.

13 . The apparatus of claim 11 , wherein the memory further includes instructions that are executable by the at least one processor to:
shift the write head according to the offset towards the adjacent track when the write status indicates the adjacent track is unused.

14 . The apparatus of claim 11 , wherein the memory further includes instructions that are executable by the at least one processor to:
determine a track overlap between the adjacent track and the target track, wherein determine the offset is based at least in part on the track overlap.

15 . The apparatus of claim 11 , wherein positioning the write head according to the offset further comprises:
position the write head by adding the offset to an unadjusted on-cylinder limit (OCLIM).

16 . The apparatus of claim 11 , wherein the memory further includes instructions that are executable by the at least one processor to:
receive a write command to write data to the target track; write to the target track using the write head positioned according to the offset; and update a track usage monitoring (TUM) table based on the writing to the target track.

17 . A system, comprising:
at least one data storage medium to store data in a shingled manner; a write head to write data to the data storage medium; at least one processor; and memory coupled to the at least one processor, wherein the memory includes instructions that are executable by the at least one processor to:
determine a write status of an adjacent track that is adjacent to a target track of the at least one data storage medium;
determine an offset for the write head based on the write status of the adjacent track, the offset comprising a physical repositioning of the write head; and
position the write head according to the offset.

18 . The system of claim 17 , further comprising:
a memory device to store a track usage monitoring (TUM) table that includes a write status for each track of the at least one data storage medium, wherein the memory further includes instructions that are executable by the at least one processor to determine the write status of the adjacent track from the TUM table.

19 . The system of claim 17 , wherein the memory further includes instructions that are executable by the at least one processor to:
shift the write head according to the offset towards the adjacent track when the write status indicates the adjacent track is unused.

20 . The system of claim 17 , wherein the memory further includes instructions that are executable by the at least one processor to:
determine a track overlap between the adjacent track and the target track, wherein determine the offset is based at least in part on the track overlap.

Assignees

• Seagate Technology Llc

Inventors

• Qiang Jian
• Liu Xiong

Classifications

• G11B20/10009

  Improvement or modification of read or write signals · CPC title

• G11B5/5526

  Control therefor; circuits, track configurations or relative disposition of servo-information transducers and servo-information tracks for control thereof (G11B5/556 takes precedence) · CPC title

• G11B5/012

  Recording on, or reproducing or erasing from, magnetic disks (G11B17/00, G11B19/00 take precedence) · CPC title

• G11B20/1217

  on discs · CPC title

• G11B2020/1238

  track, i.e. the entire a spirally or concentrically arranged path on which the recording marks are located · CPC title