AFAIK, the first program for the average
DOS user that mimicked the (now sadly lost) art of
Amiga music
tracking to near-perfection. It was developed by a Finnish guy named
Sami Tammilehto and released by the demo group he belonged to,
Future Crew.
The first encounter I ever had with tracking, apart from listening to MOD files and wondering just how the hell people made this at a time when single-bleep PC speaker soundtracks were standard, was with ScreamTracker II. This was on my 386, meaning this was somewhere in the late 80's. The cool thing about this was that, along with SoundBlaster support, Future Crew were also nice enough to provide the program with PC speaker emulation - meaning you could compose digital soundtracks without having to invest in a sound card, which were not yet standard equipment at the time.
It had four digital channels to work with, which was also Amiga standard at the time. Later, competing trackers would emerge that followed the new Amiga standard of 8 channels; the most popular of which was the 669 tracker and FastTracker II.
The whole thing, at least to me, culminated with the release of Scream Tracker 3 in 1994. Even though the program was released as a beta freeware with no support and a ton of half-implemented features that would often result in some rather interesting and completely unforeseen crashes (such as the time I altered the value of one little pitch bend command which resulted not only in the crash of the computer, but also the complete demolition of the file itself), it still kicked mondus ass. Everyone now had the pleasure of working with 32 channels (that is, if you had the base memory and processing power to cope with it).
I learned the basic ropes with Scream Tracker II, but Scream Tracker 3 was where I did many of my early musical atrocities. By the time Jeffrey Lim and his insurmountably cool Impulse Tracker came out in 1996, I was now well-versed enough in the art of tracking that the added 32 channels (now amounting to a total of 64 channels) and 16-bit samples was not received with a sigh of "oh no, more to learn", but rather hailed as a welcome addition. Plus, Impulse Tracker doesn't crash as often.
All these programs were DOS-based. There have since been countless others that have attempted to emulate them and do various funky things, most noticeably ModPlug (which operates under the Windows environment), but they all owe it to Scream Tracker; not to mention the Amiga that started the whole mess.
MIDI can get bent. All hail Sami!