A disk library is a virtual library associated with one or more mount paths. The disk library does not represent a specific hardware entity; it is a software entity that contains a list of mount paths through which data can be sent to a disk media.
Disk media, whether individual hard disks or RAID arrays, is logically divided into partitions. A partition can include some or all of the total disk storage space available. Each partition is associated with a file system path called a mount path, through which data is written to and read from.
A disk library can be configured by assigning one or more mount paths to it. The storage capacity of a disk library is determined by the total storage space in its mount paths.