I guess I'll be the one to post the obligatory Stuart Brown video:
https://youtube.com/watch?v=roBkg-iPrbw
Overall good video, it even mentions Lizardking of Triton and 4mat of Anarchy — they made some of my favorite MODs.
There are a few errors, though, like the claim that all tracker music is considered
chiptunes nowadays. Well, perhaps it is by people who don't have a clue what they're talking about, but chiptunes really are little programs for the SID chip, creating the whole sound at runtime, very unlike MIDI and MOD that use stored samples as their basis.
The video also misrepresents MIDI on the PC in an entirely wrong way, conflating AdLib with simple Wavetable cards as well as the GUS.
The strenght of the GUS was its on-board memory that you could fill with both the Gravis-provided and your own samples, and you could expand that memory, if needed. I did that using my graphics card's DRAMs, they were compatible. But you could also replace the samples of other sound cards that used wavetable sets, just not on the single patch level, like with the GUS that had its own directory for the sample files.
BTW, I've never managed to create proper music in a tracker. Instead, I made these: