Detecting damaged areas on magnetic tape based on measuring a number of servo errors

Patent metadata

Field	Value
Publication number	US-10242709-B1
Application number	US-201715849187-A
Country	US
Kind code	B1
Filing date	Dec 20, 2017
Priority date	Dec 20, 2017
Publication date	Mar 26, 2019
Grant date	Mar 26, 2019

Abstract

A computer-implemented method, according to one embodiment, includes: detecting a first error while accessing a magnetic tape, determining a first error location on the magnetic tape where the first error occurred, determining one or more areas on the magnetic tape to be examined, independent of a read and/or write operation, inducing relative motion between a tape head and the magnetic tape such that the tape head is positioned adjacent to each of the respective one or more areas in turn, using the tape head to measure a number of servo errors that occur in each of the respective one or more areas, and identifying each of the one or more areas having a respective number of measured servo errors which exceeds a threshold value as a damaged area of the magnetic tape. The one or more areas are determined using a predetermined algorithm which incorporates the first error location.

First claim

What is claimed is:

1. A computer program product for determining a damaged area of a magnetic tape loaded in a tape drive, the computer program product comprising a computer readable storage medium having program instructions embodied therewith, wherein the computer readable storage medium is not a transitory signal per se, the program instructions readable and/or executable by a processor to cause the processor to perform a method comprising:
detecting, by the processor, a first error while accessing a magnetic tape;
determining, by the processor, a first error location on the magnetic tape where the first error occurred;
determining, by the processor, one or more areas on the magnetic tape to be examined, wherein the one or more areas are determined using a predetermined algorithm which incorporates the first error location;
independent of a read and/or write operation, inducing, by the processor, relative motion between a tape head and the magnetic tape such that the tape head is positioned adjacent to each of the respective one or more areas in turn;
using, by the processor, the tape head to measure a number of servo errors that occur in each of the respective one or more areas; and
identifying, by the processor, each of the one or more areas having a respective number of measured servo errors which exceeds a threshold value as a damaged area of the magnetic tape.

2. The computer program product as recited in claim 1 , wherein the one or more areas on the magnetic tape to be examined includes a first area, wherein the first area is located adjacent to an area containing the first error location, wherein the first area is located in a same wrap of the magnetic tape as the area containing the first error location, wherein using, by the processor, the tape head to measure a number of servo errors that occur in each of the respective one or more areas includes:
using the tape head to measure a number of servo errors that occur in the first area;
in response to determining that the number of servo errors measured in the first area exceeds the threshold value, performing an iterative process which includes:
using the tape head to measure the number of servo errors that occur in a next area on the magnetic tape, wherein the next area is located longitudinally adjacent to a previously measured area of the magnetic tape determined to have a number of servo errors which exceeded the threshold value; and
determining whether the number of servo errors that occur in the next area on the magnetic tape exceeds the threshold value; and

terminating the iterative process in response to determining that the number of servo errors that occur in the next area on the magnetic tape does not exceed the threshold value.

3. The computer program product as recited in claim 2 , comprising program instructions readable and/or executable by the processor to cause the processor to:
use, by the processor, the tape head to measure a number of servo errors that occur, beginning at the next area on the magnetic tape at which the iterative process was terminated, and progressing a predetermined distance along a longitudinal direction of the magnetic tape.

4. The computer program product as recited in claim 3 , comprising program instructions readable and/or executable by the processor to cause the processor to:
determine, by the processor, whether a tape map includes records of read and/or write and/or locate operations performed in a current load of the magnetic tape,
wherein identifying each of the one or more areas as a damaged area of the magnetic tape is performed using the records in response to determining that the tape map includes the records.

5. The computer program product as recited in claim 1 , comprising program instructions readable and/or executable by the processor to cause the processor to:
determine, by the processor, whether a tape map includes records of read and/or write and/or locate operations performed in a current load of the magnetic tape,
wherein identifying each of the one or more areas as a damaged area of the magnetic tape is performed using the records in response to determining that the tape map includes the records.

6. The computer program product as recited in claim 1 , comprising program instructions readable and/or executable by the processor to cause the processor to:
determine, by the processor, one or more areas on a second wrap of the magnetic tape to be examined, wherein the second wrap is adjacent to a first wrap of the magnetic tape which includes the first error location, wherein the one or more areas are determined using the predetermined algorithm;
independent of a read and/or write operation, induce, by the processor, relative motion between the tape head and the magnetic tape such that the tape head is positioned adjacent to each of the respective one or more areas on the second wrap in turn;
use, by the processor, the tape head to measure a number of servo errors that occur in each of the respective one or more areas on the second wrap; and
identify, by the processor, each of the one or more areas on the second wrap having a respective number of measured servo errors which exceeds the threshold value as a damaged area of the magnetic tape.

7. The computer program product as recited in claim 1 , comprising program instructions readable and/or executable by the processor to cause the processor:
in response to determining that each of the damaged areas have a total longitudinal length which does not exceed a predetermined longitudinal length, perform the following process:
determine, by the processor, one or more areas on a second wrap of the magnetic tape to be examined, wherein the second wrap is a wrap located in a same data band as, but also farthest from, a first wrap of the magnetic tape which includes the first error location, wherein the one or more areas are determined using the predetermined algorithm;
independent of a read and/or write operation, induce, by the processor, relative motion between the tape head and the magnetic tape such that the tape head is positioned adjacent to each of the respective one or more areas on the second wrap in turn;
use, by the processor, the tape head to measure a number of servo errors that occur in each of the respective one or more areas on the second wrap; and
identify, by the processor, each of the one or more areas on the second wrap having a respective number of measured servo errors which exceeds the threshold value as a damaged area of the magnetic tape.

8. The computer program product as recited in claim 7 , comprising program instructions readable and/or executable by the processor to cause the processor to:
in response to determining that none of the one or more areas on the second wrap have a respective number of measured servo errors which exceeds the threshold value, perform the following process:
determine, by the processor, one or more areas on a third wrap of the magnetic tape to be examined, wherein the third wrap is located between the first and second wraps, wherein the one or more areas are determined using the predetermined algorithm;
independent of a read and/or write operation, induce, by the processor, relative motion between the tape head and the magnetic tape such that the tape head is positioned adjacent to each of the respective one or more areas on the third wrap in turn;
use, by the processor, the tape head to measure a number of servo errors that occur in each of the respective one or more areas on the third wrap; and
identify, by the processor, each of the one or more areas on the third wrap having a respective number of measured servo errors which exceeds the threshold value as a damaged area of the magnetic tape.

Assignees

• IBM

Inventors

• Yamamoto Noriko
• Miyamura Tsuyoshi
• Itagaki Hiroshi
• Hasegawa Tohru
• Matsui Sosuke
• Mitsuma Shinsuke

Classifications

• G11B20/1886 Primary

  with tapes · CPC title

• G11B2020/1826

  wherein a defect list or error map is generated · CPC title

• G11B27/36

  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)} · CPC title

• G11B5/5504

  across tape tracks · CPC title

• G11B20/182 Primary

  using test patterns · CPC title