Operating system
Urbit OS
Urbit OS sits on Nock, speaks Hoon, and runs Arvo as a kernel. Modules handle filesystem, networking, and the rest of a personal server. The important aesthetic fact: the ship’s state is a pure function of its event history. You can, in principle, replay the bird’s entire flight.
That is why people talk about a computer for a lifetime. Not because the hardware is immortal — it isn’t — but because the identity plus the log can move to new metal without becoming someone else’s product.