Patent ID: 7716417

Claim:
A host computer that accesses a tape library, the tape library comprising: a plurality of tape media; a plurality of slots in which the plurality of tape media are respectively stored; a drive in which a tape medium, among the plurality of the tape media, that has been extracted from any of the plurality of slots is set and which performs reading or writing of data in response to the setting of the tape medium; and a controller by which the tape medium is extracted from a designated slot among the plurality of slots and set in the drive; the host computer comprising: a plurality of virtual computers; a first storage region that stores slot allocation information expressing which slot, among the plurality of the slots, is allocated to which virtual computer; and an access control unit for specifying a slot that is allocated to a first virtual computer among the plurality of virtual computers based on the slot allocation information and for restricting access from the first virtual computer to a specified tape medium, among the plurality of the tape media, stored in the specified slot, wherein the host computer constitutes a cluster with another host computer that accesses the tape library, and, when any of the plurality of virtual computers that are operated by the host computer is down, the virtual computer that is down is restored by the other host computer, the host computer flirt her comprising: a third storage region that stores a host identifier of the other host computer; and a cluster control unit that copies the slot allocation information to the other host computer identified from the host identifier.