Prioritized sourcing for efficient rewriting

Patent metadata

Field	Value
Publication number	US-10691376-B2
Application number	US-201816116792-A
Country	US
Kind code	B2
Filing date	Aug 29, 2018
Priority date	Aug 29, 2018
Publication date	Jun 23, 2020
Grant date	Jun 23, 2020

Abstract

A computer-implemented method according to one embodiment includes identifying code word interleaved (CWI)-4 entries to be re-written to a data storage cartridge, selecting a subset of the CWI-4 entries to be included within a first CWI-4 set, where a plurality of the CWI-4 entries within the subset are associated with a single sub data set (SDS), and re-writing the first CWI-4 set to the data storage cartridge.

First claim

What is claimed is:

1. A computer-implemented method, comprising:
identifying code word interleaved (CWI)-4 entries to be re-written to a data storage cartridge;
selecting a subset of the CWI-4 entries to be included within a first CWI-4 set, where a plurality of the CWI-4 entries within the subset are associated with a single sub data set (SDS), and for each location within the first CWI-4 set, each SDS within a predetermined subset of SDSs from which a CWI-4 entry is selected is associated with a priority according to a predetermined re-write table; and
re-writing the first CWI-4 set to the data storage cartridge.

2. The computer-implemented method of claim 1 , wherein each CWI-4 entry includes four C1 codewords, byte interleaved.

3. The computer-implemented method of claim 1 , wherein each CWI-4 entry is created utilizing data from a single SDS.

4. The computer-implemented method of claim 1 , wherein a CWI-4 set includes a plurality of CWI-4 entries that are simultaneously written to a data storage cartridge, utilizing a write head of a data storage drive.

5. The computer-implemented method of claim 1 , wherein each CWI-4 entry within the first CWI-4 set is selected from one of four predetermined SDSs, which enables up to two CWI-4 entries from a same SDS to be included within the first CWI-4 set.

6. The computer-implemented method of claim 1 , wherein each CWI-4 entry within the first CWI-4 set is selected from one of eight predetermined SDSs, which enables up to four CWI-4 entries from a same SDS to be included within the first CWI-4 set.

7. The computer-implemented method of claim 1 , wherein neighboring locations within the first CWI-4 set are prevented from having CWI-4 entries from a same SDS.

8. The computer-implemented method of claim 1 , wherein a minimum of two CWI-4 sets are re-written to the data storage cartridge.

9. The computer-implemented method of claim 1 , wherein the first CWI-4 set is appended to CWI-4 sets previously written to the data storage cartridge during an initial write operation.

10. The computer-implemented method of claim 1 , wherein CWI-4 entries are included within the first CWI-4 set according to a predetermined re-write table, where:
each CWI-4 entry within the first CWI-4 set is selected from a predetermined subset of available SDSs, and
for each location within the first CWI-4 set, the predetermined subset of SDSs from which the CWI-4 entry is selected are indicated by the predetermined re-write table.

11. The computer-implemented method of claim 10 , wherein the predetermined re-write table is implemented in hardware of a data storage drive.

12. The computer-implemented method of claim 10 , wherein the predetermined re-write table is implemented in updateable firmware of a data storage drive.

13. The computer-implemented method of claim 1 , wherein a first half of the predetermined subset of SDSs are associated with a first priority, and a second half of the predetermined subset of SDSs are associated with a second priority.

14. The computer-implemented method of claim 13 , wherein for each location within the first CWI-4 set, if no CWI-4 entries are available for re-write from the predetermined subset of SDSs having the first priority, a CWI-4 entry is selected from the predetermined subset of SDSs having the second priority.

15. The computer-implemented method of claim 13 , wherein a predetermined first-priority subset of SDSs for a single location within the first CWI-4 set is divided into two predetermined subsets of SDSs that are included in predetermined second-priority subsets for two adjacent locations of the single location within the first CWI-4 set.

16. A computer program product for implementing prioritized sourcing for efficient rewriting, 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 executable by a processor to cause the processor to perform a method comprising:
identifying code word interleaved (CWI)-4 entries to be re-written to a data storage cartridge, utilizing the processor;
selecting a subset of the CWI-4 entries to be included within a first CWI-4 set, utilizing the processor, where a plurality of the CWI-4 entries within the subset are associated with a single sub data set (SDS), and for each location within the first CWI-4 set, each SDS within a predetermined subset of SDSs from which a CWI-4 entry is selected is associated with a priority according to a predetermined re-write table; and
re-writing the first CWI-4 set to the data storage cartridge, utilizing the processor.

17. The computer program product of claim 16 , wherein each CWI-4 entry includes four C1 codewords, byte interleaved.

18. The computer program product of claim 16 , wherein each CWI-4 entry is created utilizing data from a single SDS.

19. A data storage drive, comprising:
a processor; and
logic integrated with the processor, executable by the processor, or integrated with and executable by the processor, the logic being configured to:
identify code word interleaved (CWI)-4 entries to be re-written to a data storage cartridge;
select a subset of the CWI-4 entries to be included within a first CWI-4 set, where a plurality of the CWI-4 entries within the subset are associated with a single sub data set (SDS), and for each location within the first CWI-4 set, each SDS within a predetermined subset of SDSs from which a CWI-4 entry is selected is associated with a priority according to a predetermined re-write table; and
re-write the first CWI-4 set to the data storage cartridge.

Assignees

• IBM

Inventors

• Butt Kevin D
• Cideciyan Roy D
• Furrer Simeon
• Lantz Mark A

Classifications

• G11B5/00813

  magnetic tapes · CPC title

• G06F3/0659 Primary

  Command handling arrangements, e.g. command buffers, queues, command scheduling · CPC title

• G06F12/0607

  Interleaved addressing · CPC title

• G06F3/0604

  Improving or facilitating administration, e.g. storage management · CPC title

• G06F3/0686 Primary

  Libraries, e.g. tape libraries, jukebox · CPC title