Patent ID: 7788413

Claim:
A method for handling a MOVE MEDIUM command requesting movement of a data storage medium between two physical media libraries comprising: providing a system comprising a library access controller connected to multiple host computers by a first transport medium and connected to a first physical media library and a second physical media library by a second transport medium; receiving an original MOVE MEDIUM command from a host computer requesting movement of a data storage medium from a source element at the first physical media library to a destination element at the second physical media library, wherein the first and second physical media libraries are connected by a pass through port; generating a set of commands associated with the original MOVE MEDIUM command, including a first READ ELEMENT command, a first MOVE MEDIUM command, and a second MOVE MEDIUM command, based on the original MOVE MEDIUM command; queuing the set of commands in a queue; issuing, from the queue, the first READ ELEMENT STATUS command associated with the original MOVE MEDIUM command to the second physical media library to determine the status of the destination element; if the destination element is free, issuing, from the queue, the first MOVE MEDIUM command associated with the original MOVE MEDIUM command to the first physical media library to move the data storage medium from the source element to a first element associated with the pass through port, otherwise not issuing the first MOVE MEDIUM command; and if the first MOVE MEDIUM command is issued and completes successfully, issuing, from the queue, the second MOVE MEDIUM command associated with the original MOVE MEDIUM command to the second physical media library to move the data storage medium from a second element associated with the pass through port to the destination element, otherwise not issue the second MOVE MEDIUM command; wherein the first MOVE MEDIUM command and second MOVE MEDIUM command are configured to cause the movement specified by the original MOVE MEDIUM command.