US Patent 7620765 Method to delete partial virtual tape volumes

A virtual tape library may be configured to delete or free data blocks corresponding to expired backup images. A virtual tape volume may comprise multiple backup images, each corresponding to data stored by a backup application. The backup application may expire individual backup images of a virtual tape volume without expiring the entire virtual tape volume. In contrast to traditional virtual tape libraries, the virtual tape library described herein may delete, free and/or reuse the data blocks corresponding to expired backup images even before the entire virtual tape volume is expired.