A tape drive is a data storage device that reads and writes data onto a magnetic tape. Magnetic tape data storage is typically used for offline, archival data storage. Tape media generally has a favourable unit cost and a long archival stability.
A tape drive provides sequential access storage, unlike a hard disk drive, which provides random access storage. A tape drive must physically wind tape between reels to read any one particular piece of data. As a result, tape drives have very slow average seek times to data. However, tape drives can stream data very quickly off the tape when it hits the right position.
In computer storage, a tape library, sometimes called a tape silo, tape robot or tape jukebox, is a storage device which contains one or more tape drives, a number of slots to hold tape cartridges, a barcode reader to identify tape cartridges and an automated method for loading tapes (a robot). These devices can store immense amounts of data, currently ranging from 20 Terabyte’s up to 2.1 Exabyte’s of data or multiple thousand times the capacity of a typical hard drive and well in excess of capacities achievable with network attached storage