Avoiding debris accumulation on tape drive

Patent metadata

Field	Value
Publication number	US-9934816-B1
Application number	US-201715425062-A
Country	US
Kind code	B1
Filing date	Feb 6, 2017
Priority date	Feb 6, 2017
Publication date	Apr 3, 2018
Grant date	Apr 3, 2018

Abstract

For avoiding debris accumulation on a tape drive, a processor records a position error signal (PES) value and cumulative head turnaround count for each region of a plurality of regions of a magnetic tape. The processor further selects a first region in which to reverse travel of the magnetic tape relative to a tape head. In response to determining one of the PES value for the first region does not exceed a PES threshold and the cumulative head turnaround count for the first region does not exceed a count threshold, the processor reverses travel of the magnetic tape at the first region. In response to determining the PES value for the first region exceeds the PES threshold and the cumulative head turnaround count for the first region exceeds the count threshold, the processor selects a second region at which to reverse travel of the magnetic tape.

First claim

What is claimed is:

1. An apparatus comprising:
a processor;
a memory storing code executable by the processor to perform:
recording a position error signal (PES) value and cumulative head turnaround count for each region of a plurality of regions of a magnetic tape;
selecting a first region in which to reverse travel of the magnetic tape relative to a tape head;
in response to determining one of the PES value for the first region does not exceed a PES threshold and the cumulative head turnaround count for the first region does not exceed a count threshold, reversing travel of the magnetic tape at the first region and determining a turnaround position within the first region as a function of the cumulative head turnaround count for the first region; and
in response to determining the PES value for the first region exceeds the PES threshold and the cumulative head turnaround count for the first region exceeds the count threshold, selecting a second region at which to reverse travel of the magnetic tape.

2. The apparatus of claim 1 , the processor further determining a turnaround position within the first region that is not within a separation interval of previous turnaround positions.

3. The apparatus of claim 1 , wherein the second region is adjacent the first region.

4. The apparatus of claim 1 , wherein the second region is a region within a selection interval of the first region with one of a lowest PES value and a lowest cumulative head turnaround count.

5. The apparatus of claim 1 , wherein the PES value for each region is recorded each time the tape head passes the region.

6. The apparatus of claim 1 , wherein the cumulative head turnaround count for each region is incremented each time the magnetic tape is reversed with the tape head within the region.

7. The apparatus of claim 1 , wherein the PES value is a PES standard deviation.

8. A method for controlling a tape drive head comprising:
recording, by use of a processor, a position error signal (PES) value and cumulative head turnaround count for each region of a plurality of regions of a magnetic tape;
selecting a first region in which to reverse travel of the magnetic tape relative to a tape head;
in response to determining one of the PES value for the first region does not exceed a PES threshold and the cumulative head turnaround count for the first region does not exceed a count threshold, reversing travel of the magnetic tape at the first region and determining a turnaround position within the first region as a function of the cumulative head turnaround count for the first region; and
in response to determining the PES value for the first region exceeds the PES threshold and the cumulative head turnaround count for the first region exceeds the count threshold, selecting a second region at which to reverse travel of the magnetic tape.

9. The method of claim 8 , the method further comprising determining a turnaround position within the first region that is not within a separation interval of previous turnaround positions.

10. The method of claim 8 , wherein the second region is adjacent the first region.

11. The method of claim 8 , wherein the second region is a region within a selection interval of the first region with one of a lowest PES value and a lowest cumulative head turnaround count.

12. The method of claim 8 , wherein the PES value for each region is recorded each time the tape head passes the region.

13. The method of claim 8 , wherein the cumulative head turnaround count for each region is incremented each time the magnetic tape is reversed with the tape head within the region.

14. The method of claim 8 , wherein the PES value is a PES standard deviation.

15. A computer program product for avoiding debris accumulation, the computer program product comprising a computer readable storage medium having program instructions embodied therewith, the program instructions readable/executable by a processor to cause the processor to:
record a position error signal (PES) value and cumulative head turnaround count for each region of a plurality of regions of a magnetic tape;
select a first region in which to reverse travel of the magnetic tape relative to a tape head;
in response to determining one of the PES value for the first region does not exceed a PES threshold and the cumulative head turnaround count for the first region does not exceed a count threshold, reverse travel of the magnetic tape at the first region and determining a turnaround position within the first region as a function of the cumulative head turnaround count for the first region; and
in response to determining the PES value for the first region exceeds the PES threshold and the cumulative head turnaround count for the first region exceeds the count threshold, select a second region at which to reverse travel of the magnetic tape.

16. The computer program product of claim 15 , the processor further determining a turnaround position within the first region that is not within a separation interval of previous turnaround positions.

17. The computer program product of claim 15 , wherein the cumulative head turnaround count for each region is incremented each time the magnetic tape is reversed with the tape head within the region.

Assignees

• IBM

Inventors

• Miyamura Tsuyoshi
• Ogura Eiji
• Taketomi Tomoko
• Tsuruta Kazuhiro

Classifications

• G11B15/02 Primary

  Control of operating function, e.g. switching from recording to reproducing · CPC title

• G11B5/00813

  magnetic tapes · CPC title

• G11B20/10472 Primary

  derived from statistics of other quality measures, e.g. their mean, variance or skew · CPC title

• G11B15/444 Primary

  reversing arrangements (G11B15/442 takes precedence) · CPC title

• G11B15/44

  Speed-changing arrangements; Reversing arrangements; Drive transfer means therefor · CPC title