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qqq1one @yahoo.com [qqq1one at yahoo.com]
Hi All,
I'd like to have 2 users using separate X-sessions on the same CPU - simultaneously. That is, two different monitors plugged into two different graphic-cards (or a single dual-headed card), each matching two different keyboards and mice, but all using one CPU.
I know this can be done with Linux, but the information I found on how to do this is over a year old, is for a 2.4 series kernel, and instructs the user to patch the kernel and/or X in order to get the keyboards to be treated as separate from each other.
I'd like to avoid any patching, if possible, because I like to keep my kernel and X server up to date and don't want to have to re-patch them every time I get another update. I'm currently running an up-to-date Fedora Core 5 system (2.6.20-1.2300.fc5smp and xorg-x11-server-Xorg-1.0.1-9.fc5.6) and will be moving to a FC6 kernel and xorg-x11 server soon. I found the "startx -- -layout Multihead" command, and intend to buy a second video card (PCI-based), monitor, USB keyboard and mouse. Assuming I do a fresh install of FC6 with both sets of equipment installed, will patching still be required, and what else might I have to do? Thanks in advance.
Karl-Heinz Herrmann [khh at khherrmann.de]
Hi,
On Thu, 29 Mar 2007 22:38:37 -0700 (PDT) "qqq1one @yahoo.com" <qqq1one@yahoo.com> wrote:
> I'd like to have 2 users using separate X-sessions on the same CPU - simultaneously. That is, two > different monitors plugged into two different graphic-cards (or a single dual-headed card), each > matching two different keyboards and mice, but all using one CPU.
We've two setups at work doing that -- one 2 seats, another with three. I didn't set them up myself but it was a major headache until it finally worked. I can try to get details for you.
> > I know this can be done with Linux, but the information I found on how to do this is over a year > old, is for a 2.4 series kernel, and instructs the user to patch the kernel and/or X in order to > get the keyboards to be treated as separate from each other.
I'm pretty sure we run a recent 2.6 kernel. There are about three (or so) possibilities to separate the keyboard input (mouse is easier) for the two screens. Our first setup used the kernel patch IIRC (using Ubuntu, which already has that patch?) and uses a kdm setup which starts the two screens. Major drawback -- if one screen dies for some reason you've to reset kdm which in turn resets both screens. The 3-head system simply refused to work that way -- displays shifted, very frequent X crashes or freezes,logout on one screen reset or messed up the others screens,... .
The keyboard splitting with the event driver was not working easily as well because we had identical keyboards with the same identifiers. Now I think they are matched to the screens by their position on the USB hubs. Each user one hub. The now running three-head setup is via some meta X server -- one for all three screens -- on top of that run three kdm's with their login screens. This allows bascially to restart one kdm/X session without restarting the ground layer X server. Some caveats: Forget about 3D acceleration. And 2D speed of these screens will not make highscores in benchmarks as well -- they are quite usable, though.
> I found the "startx -- -layout Multihead" command, and intend to buy a second video card
That might or might not bring up two screens. But they both will receive the input of both keyboards if you do not separate that somehow.
K.-H.
Karl-Heinz Herrmann [khh at khherrmann.de]
I asked the fellow who set everything up....
On Fri, 30 Mar 2007 09:06:41 +0200 Karl-Heinz Herrmann <khh@khherrmann.de> wrote:
> Each user one hub. The now running three-head setup is via some > meta X server -- one for all three screens -- on top of that run three
This meta-server is calle xephyr
set everything up as described in: http://en.wikibooks.org/wiki/Multiterminal_with_Xephyr http://www.c3sl.ufpr.br/multiterminal/howtos/howto-xephyr-en.htm
And he suggests using gdm -- kdm refused to work on our system.
This makes all kernel patches unnecessary as xephyr itself handles the event distribution to the different screens.
K.-H.
qqq1one @yahoo.com [qqq1one at yahoo.com]
Thanks a bunch! I'll give it a try.