Tape drives are also called tape backup units. A tape drive can be inside the computer case or connected to the computer by a cable. An external tape drive is more expensive, but can be used with more than one computer. A tape drive stores information on tape cartridges. These cartridges are similar to the cassettes you buy at music stores.
Most people use tape drives to make backup copies of files stored on a computer.
This provides extra copies in case the original files are stolen or damanged due to viruses or computer failure.