Redhog's _(KangaroOS | http://redhog.org/Projects/Programming/Past/), an *(OS) implementing multitasking by providing a _(VM) to each process; processes can also have subprocesses that they can schedule at their liking. There is a lot of documentation and some sourcecode available, currently completely in assembler, and building under _(DOS). Development no further carried on since 1998.
