Businesses have been using tape to back up their data since the early days of computing. Tape has its limitations, but it was much cheaper than the alternatives, so its use continued.
Today, the situation is changing. The price of disk storage has come down dramatically and the performance, longevity and use characteristics of disk are far superior to tape. As a result, many businesses are looking to move away from tape for their backup and disaster recovery needs.
The key requirements of an ideal backup scheme are:
It must be economical. Large amounts of data need to be accommodated (due to the need to keep multiple versions of the data), but in many cases the data will never be accessed. Its contribution to the companys bottom line only comes if the data is needed, otherwise, it is an unnecessary expense.
It must be reliable over the long term. Some data must be stored for long periods of time, perhaps decades in some situations, to meet regulatory and business needs. If that data is ever needed it must be readable and accessible. When tape sits unused for a long period, it gets brittle and is prone to breaking and data loss.