Digital Data Storage (DDS) is a format for storing and backing up computer data on magnetic tape that evolved from Digital Audio Tape (DAT) technology, which was originally created for CD-quality audio recording. In 1989, Sony and Hewlett Packard defined the DDS format for data storage using DAT tape cartridges. Tapes conforming to the initial DDS format can be “played” by either DAT or DDS tape machines. DDS uses 3.8 mm wide tape. Initially, the tape was 60 or 90 meter long, although advancements in materials technology has allowed the length to be increased significantly in successive versions. A DDS tape drive uses helical scanning for recording, the same process used by a video cassette recorder (VCR). DDS tapes have an expected life of at least 10 years.

Source:wikipeida.org