On 5 May 2013 17:39, M. Edward (Ed) Borasky <znmeb@xxxxxxxxx> wrote: > Or better yet, what's the "minimum viable operating system?" I figured > it was Dresden Real-Time Operating System (DROPS) at one point, but > there must be something smaller. As long as it will run on any > hardware architecture, a minimum language VM - Forth, LuaJIT, JVM, > JavaScript, Scheme, Erlang, ... should do it. For me it's Openfirmware by Mitch Bradley. That's a Forth system that he originally wrote for debugging hardware in the early days of Sun Microsystems and nowadays is open source and is used for booting and hardware-debugging the OLPC XO. Great piece of engineering with one person lovingly maintaining it over decades. (Reminds me of LuaJIT -- I hope Mike keeps developing it for a long time too.) I once ported Squeak to Openfirmware to have a full graphical OS written in Forth+Smalltalk and running directly on the OLPC XO. This gave me the sense of closure that I needed to get back to normal work :-) Sorry for drifting off topic...