I was using HP Apollo systems with the Aegis OS in the early 90s, and they basically shared one filesystem across their token-ring network. Plug in two or more

I was using HP Apollo systems with the Aegis OS in the early 90s, and they basically shared one filesystem across their token-ring network. Plug in two or more systems, login to one of them, and each other system's files would be under //othersystem. I don't recall whether there were any security-minded limits you could put on what was shared, but for a team that was meant to share everything, it was pretty handy.