Sony 4mm DDS-4, 20/40GB The Sony DDS-4 is a powerful 4mm data cartridge that will help you archive large amounts of data for years to come. Featuring 20 GB of native data capacity and 40 GB compressed capacity, Sony DDS4 cartridges work quickly as you attempt sizable data backups. The Sony DDS4 is also amazingly reliable and durable. With the DDS-4 tape cartridge, it is possible to perform 100 data backups (on average) and/or 2000 tape rotations.