In Plan 9, a network connection is not an abstract socket hovering in memory; it is a physical location willed into existence by the act of looking for it.
The /net/tcp directory holds the protocol. To dial out, a process does not invoke a bespoke networking API. It simply opens the file /net/tcp/clone.
The act of opening this file triggers a state transition. The system allocates a fresh protocol control block and instantly materializes a new, numbered directory—for example, /net/tcp/7. The doorway invents the room. The process is handed a file descriptor to the ctl file inside this new private space.
To configure the connection, the process writes a plain text string to the ctl file: connect [an address]!80. To communicate, it reads and writes bytes to the adjacent data file.
Because the connection is just a directory tree, it requires no special ioctl commands or socket system calls. And because the namespace itself can be exported over the network, a process can mount another machine's /net and dial out using its hardware, completely unaware that the doorway it just opened exists on another continent.
