Library partitioning module operable to modify a request to move the medium

• US 20050013149A1
• Filed: 05/20/2004
• Published: 01/20/2005
• Est. Priority Date: 05/23/2003
• Status: Active Grant

• Current Assignee: Bridgeworks Limited
• Original Assignee: Bridgeworks Limited
• Inventors: Trossell, David
• Granted Patent: US 7,421,312 B2
• Time in Patent Office: Days
• US Class Current: 365/1
• 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 3/0614 Improving the reliability of storage systems
• CPC Class Codes: G06F 3/0664 at device level, e.g. emulation of a storage device or system
• 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 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 library partitioning module (LPM) is configured to connect multiple hosts to a tape library. The LPM comprises at least two host input/outputs, each for connection to a respective host; and a library input/output for connection to the library. The LPM is an interface between hosts and a tape library such that it allow several hosts to access the library as if they have sole use of the library'"'"'s resources. The modification of requests includes intercepting SCSI messages between robot and host and translating/transforming them. At least one tape slot for each host is allocated as a virtual import/export location. When a host sends a command to move a tape between a driver or a tape slot and an import/export location, the request is modified by the LPM so that movement occurs instead between a virtual import/export slot allocated to that host. This avoids conflicts involving the import/export location resources of the library. A handler forming part of the LPM arranges for tapes to be moved between the virtual import/export locations and the actual import/export locations. A library including partitioning and request modifying software is also disclosed.

Claims

1. A library partitioning module, for connecting plural hosts to a library, the module comprising:

at least first and second host input/outputs, each being suitable for connection to a respective host;

a library input/output, being suitable for connection to a library;

an allocator, being arranged to allocate at least a first storage element as a virtual import/export element to the first host, and to allocate at least a second storage element as a virtual import/export element to the second host; and

a modifier arranged to receive at one of said first and second host input/outputs a request, the request being to move a medium between an element and an import/export element,

the modifier being arranged to modify the request such that it constitutes a request to move the medium from one of a) said element, and b) another element to said first or second virtual import/export element, dependent on whether the request is received at the first or the second host input/output respectively, the modifier being further arranged to provide the modified request at the library input/output.

2. A library partitioning module as claimed in claim 1, in which the modifier is arranged to modify an element address forming part of the request and relating to a medium import/export element to an element address relating to a virtual import/export element, for inclusion in the modified request.

3. A library partitioning module as claimed in claim 1, including a determiner and divider arranged to determine the storage element resources of a library connected to the library input/output, and to divide the resources less the resources allocated to the virtual import/export elements between hosts.

4. A library partitioning module as claimed in claim 1, including an import/export element handler, for providing at the library input/output requests for moving media between the virtual import/export elements and one or more import/export elements.

5. A library system comprising a library partitioning module as claimed in any preceding claim, a library connected to the library input/output, the library including a robot, and plural hosts connected to respective host input/outputs.

6. A library comprising:

at least one data transfer element;

a plurality of storage elements;

at least one physical import/export element;

one or more host input/outputs, each being suitable for connection to a respective host;

an allocator for allocating at least one storage element to each host as a virtual import/export element; and

a modifier connected to receive requests at a host input/output to move a medium between one of the elements and an import/export element, and to modify each request to constitute a request to move the medium between the one of the elements or another element and an appropriate virtual import/export element.

7. A library as claimed in claim 6, including at least two host input/outputs.

8. A library as claimed in claim 6, in which the library includes only one host input/output.

9. A library as claimed in claim 6, in which the allocator is arranged to allocate to each host a number of virtual import/export elements which is greater than the number of physical import/export elements present in the library.

10. A method of operating a library partitioning module, the library partitioning module comprising a medium, an element, an import/export element, a storage element allocated as a virtual import/export element;

and a library input/output,

the method comprising;

receiving a request to move a medium between the element and the import/export element;

modifying the request to constitute a request to move the medium between one of a) the element and b) another element and the storage element; and

providing the modified request at the library input/output.

11. A method as claimed in claim 10, in which the modifying step comprises modifying an element address forming part of the request and relating to an import/export element to an element address relating to the virtual import/export element.

12. A method as claimed in claim 10, further comprising providing a request at the library input/output to move a medium between a virtual medium import/export element and a physical import/export element.

15. A computer readable medium having stored thereon machine instructions for controlling a computer apparatus to perform a method according to claim 10.

13. A method of operating a library comprising at least one data transfer element;

a plurality of storage elements;

at least one physical import/export element; and

one or more host input/outputs, each for connection to a respective host, the method comprising;

allocating at least one storage element to each host as a virtual import/export element; and

modifying a received request to move a medium between one of the elements and an import/export element to constitute a request to move the medium between the one of the elements or another element and an appropriate virtual import/export element.

14. A method as claimed in claim 13, in which the allocating step comprises allocating to each host a number of virtual import/export elements which is greater than the number of physical import/export elements present in the library.

16. A computer readable medium having stored thereon machine instructions for controlling a computer apparatus to perform a method according to claim 13.