Well, works at very low level stuff, do real virtualization, instead emulating. The most similar stuff is using VirtualBox or KVM.
DOSemu was really joy to use for gaming even on Linux+486 + 10 Megs of ram. Oh those were the days :>
I remember them fondly. 10 MB RAM, though? What kind of high roller were you?! ;)
Hehee, my dad ended up buying some demo/test machine from AST in 92 or so. The comp had quite high end specs for it's time. It actually ran really fine for long time because of switching to Linux. Stopped using it in 1998. Probably could still remember all the IO, DMA, IRQ settings for hardware ^___^