How RLP works
RLP operates differently from normal printing.
First, a new file, called
printcap(SFF),
contains information about local
and remote printers and related files needed by the print commands.
Second, the usual SCO system print commands (lp, cancel,
and lpstat) are moved to the directory /usr/lpd/remote
for safekeeping, and new versions of these commands are moved
to /usr/bin. These new commands consult the file
/etc/printcap to determine whether the print job is
going to a local printer or a remote printer attached to a print
server.
If the printer is local, printing occurs just as it would with the standard command. All standard command options are supported. This is because the new command simply invokes the standard command, now located in /usr/lpd/remote. If the printer is remote, the command spools the print job and invokes the lpd daemon. This daemon packages the print job in 4.3BSD format and sends it over the network to the host specified in the /etc/printcap file.