ABSTRACT
Tape initially gained ascendency over punched card and became a common storage format for decades until it in turn was supplanted by magnetic disk for primary storage. As disk systems were developed, the sequential nature of tape forced it into the realms of backup, hierarchical storage management (HSM) and archive. HSM is a form of storage tiering pioneered in the mainframe realm where data that is less frequently used is moved out to slower and slower storage until eventually due to economies of access, it is removed from disk entirely and placed on tape. Entire backup products were developed with around tape architectures, and it's pertinent to consider several of the key aspects offered by backup vendors to deal with tape-based limitations, since in specific cases tape offers a valid use case for backup or backup duplication purposes. The chapter also discusses where and why tape use cases have been supplanted, and the technology that has replaced them.
