Mod trackers are one of the oldest music composition programs, they use tiny samples and a keyboard interface (usually) to process the sample in a pattern. The first 2 are more advanced fast tracker style programs the latter 2 were more basic style. Trackers go back to the old Amiga and Commodore days and there have been DOS versions as well.

Side note question, does the sound chip in the N800 have any MIDI functionality?

Ken