System and method for multi-volume tape library

• US 6,260,006 B1
• Filed: 12/22/1998
• Issued: 07/10/2001
• Est. Priority Date: 12/22/1998
• Status: Expired due to Fees

• Current Assignee: Storage Technology Corp (Oracle Corporation)
• Original Assignee: Storage Technology Corp (Oracle Corporation)
• Inventors: Puckett, Timothy L., Noe, Keith F., Wong, Patrick K.
• Primary Examiner(s): Teska, Kevin J.
• Assistant Examiner(s): FREJD, RUSSELL WARREN
• Application Number:
  US09/218,256
• Time in Patent Office: 931 Days
• Field of Search: 710/1, 710/40, 711/114, 711/111, 711/2, 711/112, 711/207, 711/4, 360/77.16, 360/78.02, 369/34, 369/30, 395/82.1, 707/204
• US Class Current: 703/27
• CPC Class Codes: G06F 3/0607 by facilitating the process of upgrading existing storage systems, e.g. for improving compatibility between host and storage device
• CPC Class Codes: G06F 3/0632 by initialisation or re-initialisation of storage systems
• CPC Class Codes: G06F 3/0655 Vertical data movement, i.e. input-output transfer; data movement between one or more hosts and one or more storage devices
• CPC Class Codes: G06F 3/0686 Libraries, e.g. tape libraries, jukebox
• CPC Class Codes: G11B 15/689 Control of the cassette changing arrangement
• CPC Class Codes: G11B 2220/41 Flat as opposed to hierarchical combination, e.g. library of tapes or discs, CD changer, or groups of record carriers that together store one title
• CPC Class Codes: G11B 2220/90 Tape-like record carriers
• CPC Class Codes: G11B 27/002 Programmed access in sequence to a plurality of record carriers or indexed parts, e.g. tracks, thereof, e.g. for editing; transfer of record carriers from magazine G11B15/68, G11B17/10; G11B17/22

Abstract

A tape library system for handling multi-volume tapes includes an automated tape system with at least one tape unit and a robotic tape handling system. The tape library system receives requests from at least one host for access to a specified tape volume in a specified tape unit. The tape library system includes a tape/library control unit that receives the request from the host computer and maps the specified tape volume to a tape cartridge. The TLCU determines if the tape cartridge is currently loaded in a tape unit and, if the tape cartridge is not loaded, commands the robotic tape handling system to load the cartridge into an available unit. The TLCU forms a virtual path between the host computer and the loaded tape unit. Data is then transferred between the loaded tape unit and the host computer. Thus, the host computer is presented with a virtual view of connection to the specified tape volume loaded in the specified tape unit.

Claims

1. A tape library system for handling multi-volume tape cartridges, each tape cartridge comprising at least one tape volume, the tape library system servicing requests from at least one host computer, the system comprising:

at least one tape unit operable to write data to and read data from a tape cartridge, each of the at least one tape unit part of an automated tape system;

a robotic tape handling system operable to load tape cartridges into and remove tape cartridges from each of the at least one tape unit in the automated tape system; and

a tape/library control unit (TLCU) in communication with each of the at least one host computer, each of the at least one tape unit, and the robotic tape handling system, the tape library control unit operative to

a) receive a request from a host computer to access a specified tape volume in a specified tape unit,

b) map the specified tape volume to a tape cartridge,

c) determine if the tape cartridge is currently loaded in one of the at least one tape unit and, if the tape cartridge is not loaded, command the robotic tape handling system to load the tape cartridge into an available tape unit, a loaded tape unit thereby holding the tape cartridge,

d) form a virtual path between the host computer and the loaded tape unit, and

e) transfer data between the loaded tape unit and the host computer;

thereby presenting the host computer with a virtual view of connection to the specified tape volume loaded in the specified tape unit.

2. A tape library system as in claim 1 wherein the TLCU comprises a storage system operative to permit rapid storage and retrieval of data, the TLCU further operable to:

receive at least one write command from one of the at least one host computer to write data to a desired tape volume;

determine that the tape cartridge containing the desired tape volume is loaded into a tape unit for access to a tape volume other than the desired tape volume;

if the tape cartridge containing the desired tape volume is loaded into a tape unit for access to a tape volume other than the desired tape volume, stage the at least one write command and data to be written in the storage system;

determine when the tape cartridge containing the desired volume is not in use;

when the tape cartridge containing the desired volume is not in use, execute the at least one staged write command and write the data from the storage system to the tape cartridge containing the desired volume.

3. A tape library system as in claim 1 wherein the TLCU comprises a storage system operative to permit rapid storage and retrieval of data, the TLCU is further operable to:

receive at least one read command from one of the at least one host computer to read data from a desired volume;

determine that the tape cartridge containing the desired tape volume is loaded into a tape unit for access to a tape volume other than the desired tape volume;

if the tape cartridge containing the desired tape volume is loaded into a tape unit for access to a tape volume other than the desired tape volume, stage the at least one read command;

determine when the tape cartridge containing the desired volume is not in use;

when the tape cartridge containing the desired volume is not in use, execute the at least one staged read command.

4. A tape library system as in claim 1 wherein the TLCU is further operable to verify that data transferred between the loaded tape unit and the host computer is valid.

5. A tape library system as in claim 1 further comprising at least one user accessible tape unit that is not part of the automated tape system, the user accessible tape unit in communication with the TLCU, the TLCU further operable to transfer data between an external tape cartridge loaded in the user accessible tape unit and at least one specified tape volume, thereby allowing a user to copy at least one specified volume.

6. A tape library system as in claim 5 wherein the at least one user accessible tape unit accepts tape cartridges having a format different than tape cartridges used in the automated tape system.

7. A tape library system as in claim 5, the TLCU further operable to perform error detection and correction on data transferred between the external tape cartridge loaded in the user accessible tape unit and the at least one specified volume.

8. A tape library system as in claim 1, the TLCU further operable to:

retain a list of volumes contained on each tape cartridge;

determine a tape cartridge containing tape which requires defragmenting based on the list of volumes;

determine when at least one tape unit is available for defragmenting;

when the at least one tape unit is available, load the determined tape cartridge into one determined available tape unit; and

defragment the tape in the determined tape cartridge.

9. A tape library system as in claim 1 wherein the at least one tape unit is a plurality of tape units, the TLCU further operable to:

maintain an indication of usage for each tape unit; and

determine into which tape unit to load a tape cartridge based on the usage indication for each tape unit;

thereby balancing wear of the at least one tape unit.

10. A tape library system as in claim 1 wherein the TLCU is further operable to provide tape volume management services comprising:

tape volume password creation;

tape volume password modification;

tape volume expiration date creation;

tape volume expiration date modification;

tape volume ownership creation;

tape volume ownership modification;

tape volume import; and

tape volume export.

11. A tape library system as in claim 1 wherein a first channel is used to carry communication signals between the TLCU and at least one host computer and wherein a second channel is used to carry communication signals between the TLCU and at least one tape unit, the first channel having a different channel type than the second channel.

12. In a tape library system for handling multivolume tape cartridges, each tape cartridge comprising at least one tape volume, wherein the tape library system comprises at least one tape unit operable to write data to and read data from a tape cartridge, each of the at least one tape unit part of an automated tape system, a robotic tape handling system operable to load tape cartridges into and remove tape cartridges from each of the at least one tape unit in the automated tape system, and a tape/library control unit (TLCU) in communication with each of the at least one host computer, each of the at least one tape unit, and the robotic tape handling system, a method for servicing requests comprising:

receiving a request from a host computer to access a specified tape volume in a specified tape unit;

mapping the specified tape volume to a tape cartridge;

determining if the tape cartridge is currently loaded in one of the at least one tape unit;

if the tape cartridge is not loaded, commanding the robotic tape handling system to load the tape cartridge into an available tape unit, a loaded tape unit thereby holding the tape cartridge;

forming a virtual path between the host computer and the loaded tape unit; and

transferring data between the loaded tape unit and the host computer through the TLCU.

13. The method of claim 12 wherein the TLCU comprises a storage system operative to permit rapid storage and retrieval of data, the method further comprising:

receiving at least one write command from one of the at least one host computer to write data to a desired volume;

determining that the tape cartridge containing the desired tape volume is loaded into a tape unit for access to a tape volume other than the desired tape volume;

if the tape cartridge containing the desired tape volume is loaded into a tape unit for access to a tape volume other than the desired tape volume, staging the at least one write command and data to be written in the storage system;

determining when the tape cartridge containing the desired volume is not in use;

when the tape cartridge containing the desired volume is not determined to be accessing a tape volume other than the desired tape volume, executing the at least one staged write command and writing the data from the storage system to the tape cartridge containing the desired volume.

14. The method of claim 12 wherein the TLCU comprises a storage system operative to permit rapid storage and retrieval of data, the method further comprising:

receiving at least one read command from one of the at least one host computer to read data from a desired volume;

determining that the tape cartridge containing the desired tape volume is loaded into a tape unit for access to a tape volume other than the desired tape volume;

if the tape cartridge containing the desired tape volume is loaded into a tape unit for access to a tape volume other than the desired tape volume, staging the at least one read command;

determining when the tape cartridge containing the desired volume is not in use;

when the tape cartridge containing the desired volume is not determined to be accessing a tape volume other than the desired tape volume, executing the at least one read command.

15. The method of claim 12 further comprising verifying that data transferred between the loaded tape unit and the host computer is valid.

16. The method of claim 12 wherein the tape library system further comprises at least one user accessible tape unit that is not part of the automated tape system, the user accessible tape unit in communication with the TLCU, the method further comprising transferring data between an external tape cartridge loaded in the user accessible tape unit and at least one specified tape volume, thereby allowing a user to copy at least one specified volume.

17. The method of claim 16 wherein the at least one user accessible tape unit accepts tape cartridges having a format different than tape cartridges used in the automated tape system.

18. The method of claim 16 further comprising performing error detection and correction on data transferred between the external tape cartridge loaded in the user accessible tape unit and the at least one specified volume.

19. The method of claim 12 further comprising

retaining a list of volumes contained on each tape cartridge;

determining when a tape cartridge contains tape which requires defragmenting based on the list of volumes;

determining when at least one tape unit is available for defragmenting;

when the at least one tape unit is available, loading the determined tape cartridge into one determined available tape unit; and

defragmenting the tape in the determined tape cartridge.

20. The method of claim 12 further comprising:

maintaining an indication of usage for each tape unit; and

determining into which tape unit a tape cartridge will be loaded based on the usage indication for each tape unit.

21. The method of claim 12 further comprising:

communicating with at least one host computer over a first channel; and

communicating with at least one tape unit over a second channel having a different channel type than the first channel.