Abbreviation for Alesis Digital Audio Tape (See WFTD ADAT)/File Streaming Technology. ADAT/FST is a protocol developed by Alesis for their HD24 hard disk recording system. The machine was designed to be integrated in already plentiful ADAT systems and doesn’t use conventional hard drive reading and writing techniques such as FAT-32 or HFS. Instead it uses a much more linear scheme that in practice behaves a lot like traditional tape-based recording systems. All the data of a recorded track is kept together in associated large clusters on the disk, and managed in such a way that data doesn’t become fragmented or disassociated with other related data. This scheme has a number of potential advantages and disadvantages that are beyond the scope of this writing, but should be understood by recording engineers wishing to employ this technology.