On Tue, 11 Sep 2001, Simon Wood wrote:
Hi all, I'm setting up a system at home, similar to the ltsp, so that I can connect to/from machines on my network to a big server running X/Gnome. I have the basics working (a chooser on each machine, xdm and Gnome on server), I'm having real difficulty getting my head around the idea of local applications and how I might tie them together. Specifically I have trouble with the idea of TV Cards, CD Players/Burners and any audio (WAV, MP3) player - all of which have to be on the machine that you are sitting next to (OK audio doesn't but I want to leave some bandwidth available on my network). What is the best way of providing these services?
For applications that have to run locally but don't require intensive graphics, the easiest solution is to use ssh to connect to the "display" machine (i.e. the thin client, the workstation, the X server or whatever else you want to call it). You can do this with the command ssh -X user@hostname command_to_execute The "-X" enables X11 forwarding over the ssh connection. This means that graphical applications will still be able to display properly, but be warned that it's a very inefficient way to do local graphical apps and is not suitable for anything involving animations, 3D graphics or other intensive graphics. You can do fancy tricks like automatically extracting the hostname from the DISPLAY environment variable: #!/bin/sh LOCALCMD=$* DISPHOST=`echo $DISPLAY | perl -pe 's/^(.*):.*$/$1/'` ME=`hostname --fqdn` [ "XXX$DISPHOST" = "XXX" -o "XXX$DISPHOST" = "XXX$ME" ] && { $LOCALCMD } || { ssh -2 -X $DISPHOST "$LOCALCMD" } is a short script that can be saved as e.g. /usr/local/bin/localexec. You can then do localexec command_to_execute and it will be executed on the machine local to the display. You can also set up ssh so that you don't need to enter a password each time - you probably already know how to do this. For graphically-intensive applications, you need to muck around with ssh and xauth. The aim here is to use ssh to execute the program on the display machine but to use a direct X connection instead of routing X via ssh, because the direct connection is much faster. Unfortunately, this means you have to start delving in to X's security measures (xauth), otherwise you'll find that you will receive lots of "Client is not authorised to connect to server" errors. I can post more details about how to do this if it would help.
What happens when a user is logged in more than once?
This should not cause a problem if the distribution is well set-up. For example, under KDE a user can sometimes log on twice but then logging off either session also disconnects the other session. This should not (and does not) happen as long as KDE has been configured with remote displays (thin clients) in mind, which is certainly the case for Mandrake Linux (and I would assume for others as well). Just don't try to do obviously conflicting things like editing the same file at the same time on two different terminals, or opening a mail client on both terminals, and all should be well. HTH, Michael Brown Fen Systems Ltd. -- http://www.fensystems.co.uk/