Granted Patent B2

US 7,127,388 · App. 10/291,193 · Granted Oct 24, 2006

Abstract

Claims (35)

1. A method of interfacing a library management system software module to a virtual tape drive server module with the library management system software module resident on a host computer running an operating system (OS) and applications, where the OS provides services for inputting and outputting data sets to physical tape drives, with the services including channel commands for outputting tape mounting requests and for reading a tape, with the virtual tape drive server for receiving commands from the host to store and retrieve data from non-physical virtual tape volumes, and with the virtual tape drive server module for storing metadata describing the actual storage of the virtual tape volume contents, and with the library management system software module generating requests to cause the OS to issue messages and commands to the virtual tape drive server module to make the virtual tape drive server module status information available to the library management system software module, said method comprising:

establishing a naming convention to identify differently named administrative virtual volumes for providing different types of status information;

determining that the library management system software module requires updating of a designated type of status information;

generating, with the library management system software module, a mount request including a designated name of the administrative volume that provides the designated type of configuration metadata;

responding, at the virtual tape drive server module, to said mount request to retrieve said designated type of status information and build an administrative data set including the designated type of status information, storing said data set in a virtual tape volume, and mounting the volume on a specified virtual tape drive;

generating, with the library management system software module and the OS, read commands to the said virtual tape drive;

responding, at the virtual tape drive server module, to said read commands to transfer said administrative data set to the host for use by the library system software module.

2. A method of communicating, in real-time, policy and control messages, indicating attributes such as the performance class, media class, or storage class of a virtual volume, between a library system software module and a virtual tape drive server module, with the library system software module resident on a host computer running an operating system (OS) and applications, where the OS provides services for inputting and outputting data sets to physical tape drives, with the services including channel commands for transmitting display messages to tape drives, with the virtual tape drive server for receiving said messages and interpreting them as requests from the library management system software module to mount non-physical virtual tapes, create non-physical virtual tape volumes, and other control purposes, and with the virtual tape drive server module requiring policy and control information when creating, mounting or disposing of a virtual tape volume relating to user choices concerning virtual storage, and with requests to cause the OS to issue commands transmitting messages to the virtual tape drive server module conveying the needed policy and control information, and with the host computer including a load display interface for transmitting messages to be displayed on a display pod of a tape drive, said method comprising:

generating, using an application, a request to the OS to mount a tape volume in which to store data;

intercepting, with the library management system software module, said mount request;

building, with the library management system software module, a load display interface message in load display interface format for transmitting to the virtual tape drive server module over the load display interface channel, with said message including an identification parameter identifying eligible virtual volumes and including parameters specifying user-selected policy information relating to the selected virtual volume to be mounted;

transmitting said load display interface message to said virtual tape drive server module utilizing the load display interface channel;

responding, at said virtual tape drive server module, to said load display interface message to select a virtual volume from among the specified eligible volumes and mount said selected virtual volume and set policy parameters of said selected virtual volume equal to the policy parameters identified in said load display interface message.

3. The method of claim 2 further comprising:

determining at said virtual tape drive server module that an error condition exists;

including a field in said load display interface message identifying said message as a health check;

if an error condition, reporting an error condition to the OS when the health check message is received.

4. A tape drive emulation interface, connecting a plurality of host channels to a main processor having a systembus of a tape drive emulation system, said interface comprising:

a plurality of dual systembus base boards;

a plurality of channel interfaces disposed on each dual systembus base board, each channel interface for interfacing a host channel to input/output buffers of the main processor;

a first bus expander, multiplexing said plurality of dual systembus base boards to a bus expander port;

a first set of signal lines coupling said bus expander port to said main processor systembus.

5. The interface of claim 4 further comprising:

a backup main processor having a systembus;

a second bus expander, multiplexing said plurality of dual systembus base boards to a second bus expander port;

a second set of signal lines coupling said second bus expander port to the systembus of said backup main processor.

6. A method for transferring status information, relating to virtual volumes in a tape drive emulation system, from the virtual tape drive server to a host computer, said method comprising the steps of:

transmitting a request for status information from the host computer to the virtual tape drive server;

in response to said request, building and mounting an administrative virtual volume at said virtual tape drive server to store requested status information;

reading said administrative virtual volume to transfer said requested status information from said administrative virtual volume to said host computer.

7. A method for updating status information, relating to virtual volumes in a tape drive emulation system, from a host computer to the virtual tape drive server, said method comprising the steps of:

transmitting a request to update status information from the host computer to the virtual tape drive server;

in response to said request, mounting an administrative virtual volume at said virtual tape drive server to store updated status information;

writing to said administrative virtual volume to transfer said updated status information to said administrative virtual volume from said host computer;

reading said updated information from said administrative virtual volume to update status information at said virtual tape drive server.

Assignments (17)