File Streaming Technology

File Streaming Technology is the term used by Alesis for the proprietary file system used for their ADAT HD24 recorder which was released in 2001. FST is most notable for being designed from the ground up for audio purposes.

Limitations

The FST file system uses unsigned 32-bit sector addressing, allowing it to work with drive capacities up to 2 Terabyte.

The file system has gone through two major revisions; FST version 1.0 and the latest version, FST version 1.10. The latter adds long file names (64 characters, as opposed to 10 characters in 1.00) as well as the possibility to create up to 99 projects, each containing up to 99 songs. The file system has an undo space of roughly 3 minutes in size (1 track, 48 kHz 24 bit audio). FST stores audio of several tracks in an interlaced/adjacent manner. FST does not support virtual tracks, and as such the HD24 recorder based on it behaves much like a tape-based recorder.

Patents

According to Alesis, the file system is patent pending; however, no patents for FST are known to have been published to this date, suggesting that the patent was rejected or that the patent process was never completed.

Specifications

Since the release of the HD24, several people have had varying levels of success in reverse-engineering the FST file system specifications for interoperability purposes. This has resulted in usable third-party software capable of reading HD24 drives.