Editing Tape drive (section)

=== Data compression ===
As some data can be [[Data compression|compressed]] to a smaller size than the original files, it has become commonplace when marketing tape drives to state the capacity with the assumption of a 2:1 compression ratio; thus a tape with a capacity of 80&nbsp;GB would be sold as "80/160". The true storage capacity is also known as the [[native capacity]] or the raw capacity. The compression ratio actually achievable depends on the data being compressed. Some data has little redundancy; large video files, for example, already use compression and cannot be compressed further. A [[database]] with repetitive entries, on the other hand, may allow compression ratios better than 10:1.