Utilizing stored write environment conditions for read error recovery

• US 8,941,940 B1
• Filed: 07/17/2014
• Issued: 01/27/2015
• Est. Priority Date: 07/17/2014
• Status: Expired due to Fees

• Current Assignee: GlobalFoundries, Inc.
• Original Assignee: International Business Machines Corporation
• Inventors: Bayang, Josephine F., Gale, Ernest S., Nishida, Mitsuhiro, Nakayama, Hirokazu
• Primary Examiner(s): Sniezek, Andrew L
• Application Number:
  US14/334,603
• Time in Patent Office: 194 Days
• Field of Search: None
• US Class Current: 360/71
• CPC Class Codes: G11B 15/43 Control or regulation of mechanical tension of record carrier, e.g. tape tension
• CPC Class Codes: G11B 15/46 Controlling, regulating, or indicating speed dependent on position of tape in reserve, loop G11B15/56, G11B15/58
• CPC Class Codes: G11B 15/672 Extracting end of record carrier from container or single reel G11B15/671 takes precedence
• 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
• CPC Class Codes: G11B 33/14 Reducing influence of physical parameters, e.g. temperature change, moisture, dust
• CPC Class Codes: G11B 33/144 by detection, control, regulation of the temperature
• CPC Class Codes: G11B 5/584 for track following on tapes

Abstract

Described herein are embodiments for utilizing stored write environment conditions for read error recovery. A tape drive measures read environment conditions as a result of receiving a read command to read data from a portion of tape and compares the read environment conditions to the write environment conditions stored for that portion of tape. If the read environment conditions are not within the predetermined range of the write environment conditions, then the handling of the tape is altered to improve read element placement on the tape by accounting for expansion and contraction of the tape based on the stored write environment conditions. The handling of the tape is altered by at least one of increasing or decreasing the tension of the tape, offsetting the tape head up or down laterally with respect to the tape, and slowing down the movement of tape across the tape head.

Claims

1. A computer implemented method of utilizing stored write environment conditions of a tape of a tape cartridge in read error recovery, the method comprising:

receiving a read command to read data from a portion of said tape;

measuring a read temperature and a read relative humidity of said tape drive as a result of receiving said read command;

obtaining a write temperature and a write relative humidity stored as said write environment conditions for said portion of said tape;

comparing said read temperature to said write temperature for said portion of said tape;

comparing said read relative humidity of said tape drive to said write relative humidity stored for said portion of said tape;

determining if said read temperature is within a predetermined temperature range of said write temperature stored for said portion of said tape;

determining if said read relative humidity is within a predetermined relative humidity range of said write relative humidity stored for said portion of said tape; and

altering handling of said tape in response to at least one of a determination that said read temperature is not within said predetermined temperature range of said write temperature stored for said portion of said tape and a determination that said read relative humidity is not within said predetermined relative humidity range of said write relative humidity stored for said portion of said tape.

2. The computer implemented method of claim 1, wherein said altering handling of said tape comprises at least one of increasing a tension of said tape or decreasing said tension of said tape.

3. The computer implemented method of claim 1, wherein said altering handling of said tape comprises at least one of offsetting a tape head up laterally with respect to said tape and offsetting said tape head down laterally with respect to said tape.

4. The computer implemented method of claim 1, wherein said altering handling of said tape comprises slowing movement of said tape across a tape head.

5. The computer implemented method of claim 1, wherein said comparing said read temperature to said write temperature stored for said portion of said tape and comparing said read relative humidity to said write relative humidity stored for said portion of said tape is performed in response to receiving a read error.

6. The computer implemented method of claim 1, further comprising unmounting said tape cartridge in response to determining at least one of said read temperature and said read relative humidity are outside one of an operable temperature range and an operable relative humidity range, respectively.

7. The computer implemented method of claim 1, further comprising obtaining said write temperature and said write relative humidity from a cartridge memory of said tape cartridge.

8. The computer implemented method of claim 1, further comprising obtaining said write temperature and said write relative humidity from a non-user area of said tape corresponding to said portion of said tape.

9. The computer implemented method of claim 1, wherein data of said portion of said tape has additional data is shingled thereon, and wherein said shingled data overlaps said data to be read, the method further comprising obtaining and comparing said read temperature to a shingled write temperature stored for data shingled and overlapping said portion of said tape and obtaining and comparing said read relative humidity to a shingled write relative humidity stored for said data shingled and overlapping said portion of said tape.

10. A tape drive comprising:

a head having a plurality of read and write elements for reading data from a tape of a tape cartridge and writing data to said tape of said tape cartridge; and

a drive control system for moving said tape across said head;

wherein said tape drive is operative to;

receive a read command to read data from a portion of said tape;

measure a read temperature and a read relative humidity of said tape drive as a result of receiving said read command;

obtain a write temperature and a write relative humidity stored as said write environment conditions for said portion of said tape;

compare said read temperature to said write temperature for said portion of said tape;

compare said read relative humidity of said tape drive to said write relative humidity stored for said portion of said tape;

determine if said read temperature is within a predetermined temperature range of said write temperature stored for said portion of said tape;

determine if said read relative humidity is within a predetermined relative humidity range of said write relative humidity stored for said portion of said tape; and

alter handling of said tape in response to at least one of a determination that said read temperature is not within said predetermined temperature range of said write temperature stored for said portion of said tape and a determination that said read relative humidity is not within said predetermined relative humidity range of said write relative humidity stored for said portion of said tape.

11. The tape drive of claim 10, wherein said altering handling of said tape comprises at least one of increasing a tension of said tape and decreasing said tension of said tape.

12. The tape drive of claim 10, wherein said altering handling of said tape comprises at least one of offsetting a tape head up laterally with respect to said tape and offsetting said tape head down laterally with respect to said tape.

13. The tape drive of claim 10, further operative to obtain said write temperature and said write relative humidity from at least one of a non-user area of said tape corresponding to said portion of said tape and a cartridge memory of said tape cartridge.

14. The tape drive of claim 10, wherein said data of said portion of said tape has additional data shingled thereon, wherein said shingled data overlaps said data to be read, the tape drive further operative to obtain and compare said read temperature to a shingled write temperature stored for data shingled and overlapping said portion of said tape and obtain and compare said read relative humidity to a shingled write relative humidity stored for said data shingled and overlapping said portion of said tape.

15. A computer program product for utilizing write environment conditions of a tape of a tape cartridge for use in read error recovery, the computer program product comprising a computer readable storage medium having program code embodied therewith, the program code executable by a processor to:

receive a read command to read data from a portion of said tape;

measure a read temperature and a read relative humidity of said tape drive as a result of receiving said read command;

obtain a write temperature and a write relative humidity stored as said write environment conditions for said portion of said tape;

compare said read temperature to said write temperature for said portion of said tape;

compare said read relative humidity of said tape drive to said write relative humidity stored for said portion of said tape;

determine if said read temperature is within a predetermined temperature range of said write temperature stored for said portion of said tape;

determine if said read relative humidity is within a predetermined relative humidity range of said write relative humidity stored for said portion of said tape; and

alter handling of said tape in response to at least one of a determination that said read temperature is not within said predetermined temperature range of said write temperature stored for said portion of said tape and a determination that said read relative humidity is not within said predetermined relative humidity range of said write relative humidity stored for said portion of said tape.

16. The computer program product of claim 15, wherein said altering handling of said tape comprises at least one of increasing a tension of said and or decreasing said tension of said tape.

17. The computer program product of claim 15, wherein said altering handling of said tape comprises at least one of offsetting a tape head up laterally with respect to said tape and offsetting said tape head down laterally with respect to said tape.

18. The computer program product of claim 15, further comprising obtaining said write temperature and said write relative humidity from at least one of a non-user area of said tape corresponding to said portion of said tape and a cartridge memory of said tape cartridge.

19. The computer program product of claim 15, wherein said data of said portion of said tape has additional data shingled thereon, and wherein said shingled data overlaps said data to be read, the computer program product further configured to obtain and compare said read temperature to a shingled write temperature stored for data shingled and overlapping said portion of said tape and obtain and compare said read relative humidity to a shingled write relative humidity stored for said data shingled and overlapping said portion of said tape.

20. A computer implemented method of utilizing at least one stored write environment condition of a tape of a tape cartridge in read error recovery, the method comprising:

receiving a read command to read data from a portion of said tape;

measuring at least one read environment condition of said tape drive as a result of receiving said read command;

obtaining at least one write environment condition stored for said portion of said tape;

comparing said at least one read environment condition for said portion of said tape to at least one write environment condition stored for said portion of said tape;

determining if said at least one read environment condition is within a predetermined range of said at least one write environment condition stored for said portion of said tape; and

altering handling of said tape in response to a determination that at least one read environment condition is not within said predetermined range of said at least one write environment condition stored for said portion of said tape.