Servers are Helios processes that implement the "General Server Protocol", typically with the support of the server library. The server protocol is conceptually similar to the Unix VFS API, and more closely to Plan 9's 9P. It requires that servers represent their resources as files, with standardised open/read/write/close-style operations. Similar to facilities such as /proc in Plan 9 and other Unix-like operating systems, resources such as files, I/O devices, users, and processes are all represented as virtual files in the namespace served by their managing process.