Ultimate Soundtracker

Ultimate Soundtracker, or Soundtracker for short, is a music tracker program for the Commodore Amiga. It is the creation of Karsten Obarski, a German software developer and composer at a game development company EAS.
History.
Soundtracker started as a tool for game sound development for the Amiga. The program allowed for four-channel hardware mixing on all Amiga computers, but unlike subsequent versions, limited the number of samples/instruments in a song to 15. It allocated the four channels in strict fashion: melody (lead), accompaniment, bass, and percussion. It could export the tracks as a sequence of assembly instructions.
Soundtracker was released as a commercial product in mid 1987. It did not enjoy success as a general music development software, with reviews calling it "illogical", "difficult" and "temperamental"; it was eclipsed in that market by programs such as Aegis' "Sonix" and Electronic Arts' "Deluxe Music Construction Set". It became however a standard for games sound on the Amiga. The original code of Sound Tracker was disassembled and the modified versions of the program were spread across the burgeoning Amiga underground. A disk of instrument samples (ST-01) was distributed together with the program. In 1989, the program was improved upon by two Swedish programmers, Pex “Mahoney” Tufvesson and Anders “Kaktus” Berkeman, who released a version known as "NoiseTracker". Some versions turned out to be incompatible with the Amiga OS 2.0, causing crashes. ProTracker was another successor, released in 1991, which solved the stability problems and made several changes to the user interface.