9P (Plan 9 Filesystem Protocol or Styx)

The 9P (Plan 9 Filesystem Protocol or Styx) file system is a network-transparent, distributed OS in which windows, network connections, system interfaces, processes are represented as file systems. 9P sends messages (version; error; flush; auth; attach; walk; create; open; read; write; clunk; stat; wstat) between clients and servers which represent the entry points in the Virtual File System layer. The client to a server as T-messages and the server replies as R-messages.