What is Tape Backup?
A general term for a class of devices for backing up data to a magnetic tape for disaster recovery planning and archiving purposes. A number of technologies with incompatible tape formats have been implemented in these devices.
The following list describes some of the formats. Note that the capacity and speed of tape drives is rapidly improving. This list gives you an idea of the range of possibilities. Note also that the capacities mentioned in this list are for uncompressed data.
With data compression, most of these formats can approximately double the amount of data they hold.
Digital audio tape (DAT): 4-millimeter tape manufactured by a number of different vendors that has tape cartridge capacities of 4 GB and higher. DAT drives use the DDS-2 format for 4-GB tape cartridges, the DDS-3 format for 12-GB cartridges, and the DDS-4 format for 20-GB cartridges. Transfer speeds are typically 1.5 Mbps or higher. DAT cartridges are standardized with a 3.5-inch form factor.
Quarter-inch cartridge (QIC): Quarter-inch tape manufactured by Tandberg Data that can have tape cartridge capacities of 13 GB and higher. QIC generally uses 5.25-inch cartridges, but these are being replaced with 3.5-inch minicartridges. Transfer speeds are typically 1.5 Mbps or higher.
8 millimeter: Can have tape cartridge capacities of 20 GB and higher. Transfer speeds are typically 3 Mbps or higher. 8-millimeter tapes have a form factor of 5.25 inches. Sony and Exabyte are two manufacturers of 8-millimeter tapes.
Digital linear tape (DLT): Uses technology developed by Digital Equipment Limited (which was acquired by Quantum in 1994). DLT can have tape cartridge capacities of 25 GB and higher. Transfer speeds are typically 5 Mbps or higher. DLT cartridges have a form factor of 5.25 inches. Quantum and Tandburg are two manufacturers of DLT.