Digital Data Storage. A helical scan tape media format for data. Uses the same mechanism as DAT, albeit with different tape compositions. DDS-1 media stores 2GB per tape, while DDS-2 media stores 4GB and DDS-3 stores 8GB. All next-generation standards retain backwards compatability with the previous ones. Note that DATADAT is not considered to be part of the DDS family and is not readable by most DDS tape devices.