It always amazes me how hardcore coders can extend and squeeze the maximum out of computer hardware, especially "obsolete" ancient systems such as the Contiki operating system that can run on the likes of Commodore 64 and yet has full networking and even a GUI. A2osX is another interesting project, it is a "a cooperative, event-driven multitasking kernel", well nothing too unusual about that... except that its for the Apple IIe. Yes thats right Apple's first big selling computer from the late 1970s and early 1980s. An 8-bit machine.
However my IIe cannot run A2osX as it needs 128K of RAM, i believe mine is only 32K (though to be honest its been so long since its booted up i can't remember). My IIe is content to remain sleeping in the loft next to its pal the Apple IIc.