[coderatlarge]

thanks - in that vein there's also freeDOS. but I assume if someone had built a learning OS they could make it much smaller?

haven't tried:

http://randomcomputerbits.blogspot.com/2008/02/tutorial-inst...

[yencabulator]

DOS just isn't much of an operating system, it's more like a bunch of helper functions preloaded into RAM, and you're free to do whatever you want with or without them.