.TH COMSAT 8C "4 March 1983"
.UC 4
.SH NAME
comsat \- biff server
.SH SYNOPSIS
.B /etc/comsat
.SH DESCRIPTION
.I Comsat
is the server process which listens for reports of incoming mail
and notifies users if they have requested this service.
.I Comsat
operates with two processes.  The parent process simply waits
on the child process, in case it dies for some reason.  The
child process performs the actual work. 
.I Comsat
listens on a datagram port associated with the ``biff'' service
specification (see
.IR services (5))
for one line messages of the form
.PP
.ti +0.5i
user@mailbox-offset
.PP
If the
.I user
specified is logged in to the system and the associated terminal has
the owner execute bit turned on (by a ``biff y''), the
.I offset
is used as a seek offset into the appropriate mailbox file and
the first 7 lines or 560 characters of the message are printed
on the user's terminal.
.SH FILES
.DT
/etc/utmp	to find out who's logged on and on what terminals
.SH "SEE ALSO"
biff(1)
.SH BUGS
Sometimes 
.I comsat
gets stuck and the child process must be killed off to get
things going again.
.PP
Users should be notified of mail which arrives on other
machines than the one they are currently logged in to.
.PP
The notification should appear in a separate window so it
does not mess up the screen.