9P Protocol FAQ

What is 9P2000?

9P2000 is the latest version of the 9P protocol which was introduced with Plan 9 from Bell Labs 4th Edition; it introduced certain simplifications of the protocol. Previous versions of the protocol are deprecated and are rarely used anymore.

What is the difference between Styx and 9P?

In all recent versions of Inferno Styx is the same as 9P2000. Styx was a variant of the original 9P protocol for Inferno, most of those changes were rolled into 9P2000 and Inferno itself switched to use the new version of the protocol but keep the same name. This days some people use the name ‘Styx’ to mean 9P2000 using Inferno authentication by default.

What is 9P2000.u(aka .u)?

It is a set of deprecated extensions to 9P2000 as part of the v9fs project to support aspects of legacy Unix file systems that 9P never included because Plan 9 didn’t need them(eg., symlinks, SUID bit, etc).