[gunapologist99]

I love UML. I used to use it all the time. Is it still developed? It was really a pretty slick system and very easy to work with.

http://user-mode-linux.sourceforge.net/

(another good site: https://wiki.archlinux.org/title/User-mode_Linux )

[kasabali]

It's in mainline kernel (can be compiled as an architecture), but I don't think it's being actively developed.