In Plan 9 and Inferno, the key ideas are the protocol for communicating between components and the simplification and extension of particular concepts. In Plan 9, the key abstraction is the file system-anything you can read and write and select by names in a hierarchy-and the protocol exports that abstraction to remote channels to enable distribution. Inferno works similarly, but it has a layer of language interaction above it through the Limbo language interface-which is like Java, but cleaner I think.