The best semi-professional music creation tool available, in my opinion. Easy to use once you got into it, and the results can compete with professional commercial music.

As far as I know, it's been written in C, and not in assembly, by the Australian programmer Jeffrey Lim. The first version was available in 1995, the latest one 2.14) is from 1998.

Since 2000 DSPaudio, Inc. has been working on its successor IT3, but it seems they have stopped the development.