DDS4

DDS4, also known as DDS-4, is a data storage format used on 4 millimeter DAT tapes as part of the Digital Data Storage (DDS) family. It was introduced in the mid- to late-1990s as an incremental upgrade over DDS-3, aiming to provide higher capacity and better performance for backup and archival tasks.

The format uses 4 mm DAT tapes in cartridge form. DDS-4 offered greater data density and improved error correction compared with its predecessors, enabling higher native storage capacity and faster write and read operations. Typical native capacities for DDS-4 cartridges were in the vicinity of a few tens of gigabytes, with compressed capacities dependent on data compressibility and drive implementation. Data transfer rates were modest by modern standards but sufficient for many small to mid-sized backup tasks, with performance generally higher than DDS-3 and improved reliability due to enhanced error management.

Compatibility for DDS-4 is largely confined to drives designed to handle DDS-4 media. In many cases, DDS-4 tapes could not be reliably read by older DDS-3-only drives, and backward compatibility was not guaranteed across all devices. As with other DDS generations, tape media and drives from different manufacturers varied in their ability to interoperate, so users typically matched DDS-4 media with a DDS-4-capable drive.

Usage and legacy: DDS-4 served as a common backup solution in the late 1990s and early 2000s, especially in small to medium enterprises and workgroups. Over time, the range of DAT formats diminished in favor of newer technologies such as LTO, leading to reduced adoption of DDS-4. In contemporary contexts, DDS-4 is mostly encountered in legacy systems and archived media rather than new installations.