What a blast from the past. I recall my own experimenting with DJGPP and DPMI in my own software. It felt futuristic at the time. I was blown away.

Another fond memory: I was playing Star Wars: Dark Forces (I think that was the one) and was frustrated with the speed of level loading. I think it used DOS/4GW and I recall renaming it, copying in a new dos extender (was it CWSDPMI? not sure), and renaming it to the one Star Wars used. I was shocked when it not only worked, but the level loading was MUCH faster (like 3-5x faster I recall). My guess is whatever one I had swapped in wasn't calling the interrupt in DOS (by swapping back to real mode), but perhaps was calling the IDE disk hw directly from protected mode. Not sure, but it was a ton faster, and I was a very happy kid. The rest of the game had the same performance (which makes sense I think) with the new extender.