Mass storage devices are storage devices with large storage capacity. They are used for backups, as well as for mass data storage with fast access. Their storage capacity is in the range of gigabytes and terabytes.
If magnetic disk storage, hard disk drives, removable disk drives and tape drives are mainly used for mass data backup, compact discs( CD), DVDs, HD-DVDs, Ultra Density Optical( UDO), Professional Disc for Data ( PDD), Advanced Optical Disc ( AOD), Multiplexed Optical Data Storage ( MODS), Holographic Versatile Disc ( HVD), magneto-opticalstorage and hard disks are used for fast direct access.
In addition to single drives, JBOD systems are used for mass storage, as are systems with automatic changing mechanisms such as jukeboxes, and robotic systems that manage hundreds and thousands of magnetic tapes. These include tape libraries, the Tape Libraries and the Automated Tape Libraries( ATL).