Today when storage capacities grow rapidly traditional tape backup systems lose their urgency. However, magnet tapes with all its advantages and disadvantages still used by companies from small business to enterprise. The reason is in very high reliability of magnet tape for data storage. It has much longer life than other storage devices.
Tape backup is making a reserve copy using tape drive. It is a data storage device which reads and writes data stored on magnetic tape typically used for archival storage from hard drives. Tape backup drives can range in capacity from a few megabytes to hundreds of gigabytes, uncompressed. In marketing materials, tape storage is usually referred to with the assumption of 2:1 compression ratio, so a tape drive might be known as 80/160, meaning that the true storage capacity is 80 whilst the compressed storage capacity can be approximately 160 in many situations.
Instead of allowing random access to data as hard disk drives do, tape backup drives only allow for sequential access of data. A hard disk drive can move its read/write heads to any random part of the disk platters in a very short amount of time, but a tape drive must spend a considerable amount of time winding tape between reels to read any one particular piece of data. As a result, tape drives have very slow average seek times. Despite the slow seek time, tape drives can stream data to tape very quickly. For example, modern drives can reach continuous data transfer rates of up to 80 MB/s, which is as fast as most 10,000 rpm hard disks.