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Re: [LUG] Multihead X (was debian code names)


 On 17/07/2010 12:11, Grant Sewell wrote:

What I would like to do something is investigate multi-seat X, that
is having two monitors, two keyboards and two mice (and maybe two
soundcards) attached to one machine and creating two 'independent'
desktops which can be used (kind of in a way like LTSP but with
only one machine and no server).

I've been looking into it but I've had so much on my plate and a
lack of space and hardware that I haven't really done much about
it.  I did try and get it working a couple of years back but had no
joy.  However maybe if a few of us got together one day with some
hardware we could possibly get something up and running.  Something
like this could possibly be a great way of using resources, such as
when a reasonable spec (say Athlon XP, Athlon 64, Pentium 4) PC is
donated to somewhere we could turn the one machine into two
It ought to be possible.
It is.  Last time I looked into it it worked but wasn't especially
stable... ie if user B logged out, then user A's X session was also
killed while the login manager restarted.  Not clever.

I've read that on Ubuntu at least they're working on getting X to run as a user rather than root, maybe that might resolve the issues. Saying that I don't know when it's going to be integrated into a distro.
You'll need a seconds keyboard and mouse (USB or old serial?) and a
system with 2 graphics cards.
2 x USB mice, 2 x USB keyboards, 2 x PCI(e) GFX cards.
USB because they can each be identified individually, likewise for the
GFX cards.  Once the devices can be uniquely identified, you can set up
X to have specific keyboard, mouse and GFX card as a single X session,
and the other keyboard/mouse/GFX card as a different X session.

Last time I tried it I was using a single dual head graphics card, I think that didn't help. I guess a PCIe and PCI card in a box might do the job.

You might make it work by using some sort of virtualisation and
giving each host access to it's own graphics/keboard/mouse. If that
works, you could probably have as many desktops as you've got slots
to plug graphics cards into... (Assuming you can share the USB bus
Sounds like overkill. :D
Can't say it's a project that enthuses me though :)
I tried it a few years back with my BTEC students.  It was fun, but a
bit over their heads I think.  Might try it again soon. :)

I'd be interested to know how you get on, as I say it's something I've wanted to try. It is possible at the moment with a proprietary package which I believe is called Userful, it's available for personal use giving 2 machines although the paid for version can support up to 10 machines (presumably using a load of dual head graphics cards).


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