Apparatus and method for controlling transportation of tape medium

• US 9,646,644 B2
• Filed: 12/16/2015
• Issued: 05/09/2017
• Est. Priority Date: 12/22/2009
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Katagiri, Takashi, Mori, Yuhko, Oishi, Yutaka
• Primary Examiner(s): Wong, K.
• Application Number:
  US14/972,046
• Publication Number:
  US 20160104506A1
• Time in Patent Office: 510 Days
• Field of Search: None
• CPC Class Codes: G06F 3/0613 in relation to throughput
• CPC Class Codes: G06F 3/0656 Data buffering arrangements
• CPC Class Codes: G06F 3/0682 Tape device
• CPC Class Codes: G11B 15/20 Moving record carrier backwards or forwards by finite amounts, i.e. backspacing, forward spacing
• CPC Class Codes: G11B 15/26 Driving record carriers by members acting directly or indirectly thereon G11B15/44 takes precedence; driving features inside container, see G11B23/04 and subgroups
• CPC Class Codes: G11B 15/442 Control thereof
• CPC Class Codes: G11B 15/444 reversing arrangements G11B15/442 takes precedence
• CPC Class Codes: G11B 20/10009 Improvement or modification of read or write signals
• CPC Class Codes: G11B 20/10527 Audio or video recording; Data buffering arrangements G11B20/12 - G11B20/18 take precedence
• CPC Class Codes: G11B 2020/10759 content data
• CPC Class Codes: G11B 2220/90 Tape-like record carriers
• 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 5/00813 magnetic tapes

Abstract

An apparatus, computer readable medium device, and method for controlling transportation of a tape medium. A determination is made whether to execute a backhitch operation in response to writing a data set to tape from the buffer. If not, a determination is made whether a transaction size at which data is transferred from the buffer to the tape is less than a buffer size. If so, then a determination is made of a a new speed and whether a current speed is different from the determined new speed. If so, then a backhitch is initiated.

Claims

1. An apparatus for controlling transportation of a tape medium during data writing to the tape medium, comprising:

a buffer;

a controller that performs operations, the operations comprising;

calculating a first time to write data at a first tape speed level from a tape speed table and considering a first time required to execute a backhitch at the first tape speed level;

calculating a second time to write data at a second tape speed level from the tape speed table and considering a second time required to execute a backhitch at the second tape speed level; and

using the first tape speed level for operations in response to the second time to write data being less than the first time to write data.

2. The apparatus of claim 1, wherein the first tape speed level corresponds to a first tape speed greater than a second tape speed corresponding to the second tape speed level.

3. The apparatus of claim 1, wherein the first time to write data is calculated using a first tape speed for the first tape speed level and a first write data rate for the first tape speed level, and wherein the second time to write data is calculated using a second tape speed for the second tape speed level and a second write data rate for the second tape speed level.

4. The apparatus of claim 3, wherein the operations further comprise:

calculating a first backhitch using the first tape speed, wherein the first backhitch is used to calculate the first time to write data; and

calculating a second backhitch using the second tape speed, wherein the second backhitch is used to calculate the second time to write data.

5. The apparatus of claim 3, wherein the operations further comprise:

calculating a first maximum length of tolerable idle transport for achieving a target data read rate using the first write data rate, wherein the first maximum length is used to calculate the first time to write data; and

calculating a second maximum length of tolerable idle transport for achieving the target data read rate using the second write data rate wherein the first maximum length is used to calculate the first time to write data.

6. The apparatus of claim 1, wherein the operations further comprise:

calculating a third time to write data at a third tape speed level from the tape speed table and considering a third time required to execute a backhitch at the third tape speed level in response to the first time to write data being less than the second time to write data; and

using the second tape speed level for operations in response to the third time to write data being less than the second time to write data.

7. The apparatus of claim 6, wherein the operations further comprise:

determining whether the second tape speed level is a last tape speed level in response to the first time to write data being less than the second time to write data, wherein the third time to write data is calculated in response to determining that the second tape speed level is not the last tape speed level; and

using the second tape speed level for operations in response to determining that the second tape speed level is the last tape speed level.

8. The apparatus of claim 6, wherein the using the second tape speed level comprises using the second tape speed level to determine whether to use Same Wrap Backhitchless Flush (SWBF) or backhitch to write data to the tape medium.

9. A computer readable medium device including a program executed to control transportation of a tape medium during data writing from a buffer to the tape medium and perform operations, the operations comprising:

calculating a first time to write data at a first tape speed level from a tape speed table and considering a first time required to execute a backhitch at the first tape speed level;

calculating a second time to write data at a second tape speed level from the tape speed table and considering a second time required to execute a backhitch at the second tape speed level; and

using the first tape speed level for operations in response to the second time to write data being less than the first time to write data.

10. The computer readable medium device of claim 9, wherein the first tape speed level corresponds to a first tape speed greater than a second tape speed corresponding to the second tape speed level.

11. The computer readable medium device of claim 9, wherein the first time to write data is calculated using a first tape speed for the first tape speed level and a first write data rate for the first tape speed level, and wherein the second time to write data is calculated using a second tape speed for the second tape speed level and a second write data rate for the second tape speed level.

12. The computer readable medium device of claim 11, wherein the operations further comprise:

calculating a first backhitch using the first tape speed, wherein the first backhitch is used to calculate the first time to write data; and

calculating a second backhitch using the second tape speed, wherein the second backhitch is used to calculate the second time to write data.

13. The computer readable medium device of claim 11, wherein the operations further comprise:

calculating a first maximum length of tolerable idle transport for achieving a target data read rate using the first write data rate, wherein the first maximum length is used to calculate the first time to write data; and

calculating a second maximum length of tolerable idle transport for achieving the target data read rate using the second write data rate wherein the first maximum length is used to calculate the first time to write data.

14. The computer readable medium device of claim 9, wherein the operations further comprise:

calculating a third time to write data at a third tape speed level from the tape speed table and considering a third time required to execute a backhitch at the third tape speed level in response to the first time to write data being less than the second time to write data; and

using the second tape speed level for operations in response to the third time to write data being less than the second time to write data.

15. The computer readable medium device of claim 14, wherein the operations further comprise:

determining whether the second tape speed level is a last tape speed level in response to the first time to write data being less than the second time to write data, wherein the third time to write data is calculated in response to determining that the second tape speed level is not the last tape speed level; and

using the second tape speed level for operations in response to determining that the second tape speed level is the last tape speed level.

16. The computer readable medium device of claim 14, wherein the using the second tape speed level comprises using the second tape speed level to determine whether to use Same Wrap Backhitchless Flush (SWBF) or backhitch to write data to the tape medium.

17. A method of controlling transportation of a tape medium during data writing from a buffer to the tape medium, comprising:

calculating a first time to write data at a first tape speed level from a tape speed table and considering a first time required to execute a backhitch at the first tape speed level;

calculating a second time to write data at a second tape speed level from the tape speed table and considering a second time required to execute a backhitch at the second tape speed level; and

using the first tape speed level for operations in response to the second time to write data being less than the first time to write data.

18. The method of claim 17, wherein the first tape speed level corresponds to a first tape speed greater than a second tape speed corresponding to the second tape speed level.

19. The method of claim 17, wherein the first time to write data is calculated using a first tape speed for the first tape speed level and a first write data rate for the first tape speed level, and wherein the second time to write data is calculated using a second tape speed for the second tape speed level and a second write data rate for the second tape speed level.

20. The method of claim 19, further comprising:

calculating a first backhitch using the first tape speed, wherein the first backhitch is used to calculate the first time to write data; and

calculating a second backhitch using the second tape speed, wherein the second backhitch is used to calculate the second time to write data.

21. The method of claim 19, further comprising:

calculating a first maximum length of tolerable idle transport for achieving a target data read rate using the first write data rate, wherein the first maximum length is used to calculate the first time to write data; and

calculating a second maximum length of tolerable idle transport for achieving the target data read rate using the second write data rate wherein the first maximum length is used to calculate the first time to write data.

22. The method of claim 17, further comprising:

calculating a third time to write data at a third tape speed level from the tape speed table and considering a third time required to execute a backhitch at the third tape speed level in response to the first time to write data being less than the second time to write data; and

using the second tape speed level for operations in response to the third time to write data being less than the second time to write data.

23. The method of claim 22, further comprising:

determining whether the second tape speed level is a last tape speed level in response to the first time to write data being less than the second time to write data, wherein the third time to write data is calculated in response to determining that the second tape speed level is not the last tape speed level; and

using the second tape speed level for operations in response to determining that the second tape speed level is the last tape speed level.

24. The method of claim 22, wherein the using the second tape speed level comprises using the second tape speed level to determine whether to use Same Wrap Backhitchless Flush (SWBF) or backhitch to write data to the tape medium.