I understand an OS to be something like the "base" software that runs on a single computer to unify the various pieces of hardware that are in it. I was surprised that this is a distributed system, but on second thought, it makes sense: "multiple CPU's" is just really "more hardware". The network is just another bus, in a sense. In my opinion it's an extra "innovation token" though, since it's not standard practice to build distributed OS's. With the addition of building a database-oriented system is going to be a hell of a challenge.