.TH MUX 3 
.SH NAME
mux \- server registry and service multiplexor
.SH SYNOPSIS
.nf
.B bind #s /srv

.BI #s/ service1
.BI #s/ service2
 ...
.fi
.SH DESCRIPTION
Mux is a replacement for
.IR srv (3)
that allows a single file server to provide
service to processes on both local and remote machines.
.I Mux
performs all the functions of
.BR srv .
.PP
Plain files created in the top level directory of
.I mux
behave exactly as described
in
.IR srv (4).
.PP
Creating a directory in
.I mux
produces a stream multiplexer.  Many clients may write
messages to a single server.
.I Mux
prefixes each message with a connection
number to allow the server to distinguish between clients.  Messages written back
to
.IR mux
by the server are prefixed by a destination connection number.
.I Mux
removes the destination connection number before passing messages back to its clients.
.PP
When created, a
.I mux
directory contains two files,
.B head
and
.BR clone .
Opening the clone
file allocates a new connection on the multiplexer.
The file descriptor returned
is suitable for mounting (see
.B mount
in
.IR bind (1)
or
.IR bind (2)).
A file named by the new connection number
is produced by opening the
.B clone
file.
The numbered connection file may be used to
read and write messages to the server.
The
.B head
file should be used by the server
to send and receive message from the clients.
.PP
A file server must be linked with
.B /$objtype/lib/libmux.a
to use the device.  The library uses the
connection numbers provided by the driver to map the fid space of the various
client mount drivers into a single fid space for the server.
.B Libmux
replaces
.B convS2M
and 
.B convM2S
(see
.IR fcall (2))
from the C library.
A server linked with
.B libmux
will work correctly
with a normal
.B srv
entry.
.PP
.IR Mux 's
only use is to allow CPU servers to act as a gateway to a file system.
It is not normally configured in a system.
.SH BUGS
This should be unnecessary but is required to overcome a failure of vision.
.SH SEE ALSO
.IR bind (2),
.IR srv (4)