(Virtual Library System) software emulation of a library providing a disk storage space in the form of a files system to protect data. The management of virtual hardware emulation of tapes is performed by the backup server or the storage node as well as the virtual tapes migration mechanism to physcial tapes (D2D2T).
(Virtual Tape Library) hardware emulation of a library providing a virtual disk storage volume to protect data. The tape drive the arm and the geometry of the library are emulated and presented to the backup server or the storage node in the same way as a physical library. The migration of virtual tapes mechanism to physical tapes (D2D2T) is transparent and is not managed by the backup software.