BareMetal OS uses "jobs" instead of threads: http://vimeo.com/13423853
I was going for something similar to Apple's Grand Central Dispatch.
Thread vs job model for fine grained parallelism
Re: Thread vs job model for fine grained parallelism
BareMetal OS - http://www.returninfinity.com/
Mono-tasking 64-bit OS for x86-64 based computers, written entirely in Assembly
Mono-tasking 64-bit OS for x86-64 based computers, written entirely in Assembly