/dev (file type: socket device?)

blackzone · 08-10-2004, 12:49 AM

was reading the /dev directory of a firmware.

I see some of the files indicated as type "s" socket type.
Have filesize of 0. And indicate as a pink color followed by a "=" sign.

can give some insight what is a socket device and why/how people custom make one?

rjlee · 08-10-2004, 04:15 AM

Unless I'm mistaken, “s” refers to a FIFO socket. See the FIFO(4) manual page for more details.

Basically, a FIFO refers to a small in-memory buffer that one process can write to while another one reads from. The processes are controlled by SIGSTART/SIGSTOP (I think) so that you can never write to a full buffer or read from an empty one.

You can create a FIFO socket or “named pipe” using the command:

Code:

mkfifo filename

Hope that helps,

— Robert J. Lee