Creating a 1980s virtual world

I’m currently reading True Names and the Opening of the Cyberspace Frontier (US, UK) which is based around the story by Vernor Vinge with a lot of mostly cryptography-related essays padding the volume out. One of the best essays however is by Chip Morningstar and recounts the building and running of Habitat, an online multi-player world using Commodore 64 computers whose construction began in 1985. I’d never seen it before, and while the hardware on which the software ran is old the essay is still, I’m sure, remarkably relevant. Not to mention entertaining.