The difference is PharoNOS has a Linux running behind while the idea of SqueakNOS is to build a complete operating system via Squeak. In this way you can quickly hack it. There is a great page about these initiatives here: http://wiki.squeak.org/squeak/5727
I was going to mention QNX Demo Disk in my UNIX alternatives comment. I think I edited it out for a weak fit to the post. It was an amazing demo, though, showing what a clean-slate, alternative, RTOS architecture could do for a desktop experience. The lack of lag in many user-facing operations was by itself a significant experience. Showed that all the freezes and huge slow-downs that were "to be expected" on normal OS's weren't necessary at all. Just bad design.
It's neat that it was the thing that inspired one of your Squeak projects. Is SqueakNOS usable day-to-day in any console desktop or server appliance context? Key stuff reliable yet?
We implemented SqueakOS while some friends implemented SqueakNOS. I don't think they are being used anywhere but for educational purposes it is amazing that drivers and a TCP/IP stack could be implemented (and debugged!) in plain smalltalk. There was some more information here: http://lists.squeakfoundation.org/pipermail/squeaknos/2009-M...
