Because tape volumes can reside either inside libraries or on shelves
outside the library, physical procedures for accessing volumes vary
according to their location:
- When a library-resident volume is requested, the system mounts
it on a tape drive in the tape library containing the volume.
- When a shelf-resident volume is requested, the installation is
given the opportunity to enter the volume into a tape library by using
the volume not in library installation exit. If the volume is not
entered into the library, the system requests the volume be mounted
on a nonlibrary device (stand-alone tape drive).
Note: Shelf storage
may be local to the computer facility and, therefore, accessible to
the operator, or it may be located at another location.