In its simplest form, a library consists of data storage media and the device used to read from and write to the media. The group of libraries and associated media that are managed by a Removable Storage installation is called a Removable Storage system. There are two major types of libraries:
Automated libraries are automated units that hold multiple tapes or disks, and some have multiple drives. These libraries are sometimes called changers or jukeboxes, and commonly use robotic subsystems to move media stored in the library's storage slots. Automated libraries can also consist of other hardware components that are managed by Removable Storage, such as doors, inject/eject ports, cleaner cartridges, and bar code readers.
Stand-alone drive libraries, or stand-alone drives, are single-drive, nonautomated units, such as tape or CD-ROM drives, that hold a single tape or disk. With these, you manually insert a tape or disk into the unit.
Not only can Removable Storage manage multiple libraries, but it can also track offline media that are not currently contained in a library. These media might be anywhere: on a shelf or in a drawer. Every tape or disk that is offline belongs to a library.