How do 250 scientists spend their coffee break at a scientific conference? They use KDE! There was a scientific conference, the Tübinger Perception
Conference 2005 (TWK) at the end of February. Many scientists from all over the world joined to take part in the symposia and the poster sessions. Because many scientists are addicted to their e-mail, the organizers installed an Internet Corner with 3 KDE Terminals.
This setup was a little bit special, because one PC served 3 GeForce graphic adapters with
2 TFTs and 1 old SGI monitor, 3 keyboards and 3 mice attached. Under normal circumstances, you can only attach
1 monitor, 1 keyboard and one mouse to a computer. If you attach more than these, all keyboards and mice are
combined into one!
But a modern PC is idle most of the time, especially for internet tasks, and the processor load is not as important
as the network speed. So the idea was to setup one PC with several graphic adapters serving several terminals
with KDE as the GUI.
To run a multi-localuser X system is not a big problem. The so-called
backstreet ruby provides this functionality as a simple kernel patch for Linux 2.4 and 2.6. As soon as the system is running, a sysctr command breaks up the input
device binding. To speed up the whole system, we also applied the
low latency patch, but didn't measure its effect.
The 3 X servers in our setup were started automatically by a script at boot time. No login was
necessary, KDE starts up without any user interaction but with unprivileged user rights. The KDE version was 3.3.1.
This is not the most current version but, as this setup was done in 5 hours, there was little time left to update program
versions from the existing state. Anyhow: 3.3.1 is fancy enough for the scientists to read online tickers and ssh to their university account to start Pine!
The biggest challenge for us was to find out which keyboard and mouse were associated with which monitor. While this was a static
mapping, the mouse mapping changed with every system startup. This problem was not understood, but finding out
which of the 3 mice belonged to which monitor wasn't so difficult. Because the system was very stable, this was only necessary three times in total.
The participants loved the setup and many of them were very surprised to see one PC with 3 independent monitors.
Some of them had a little hesitation using the printer, although printing is very simple with KDEPrint.
Nobody reported problems with the desktop, although many of them use XP for their daily desktop work. The most
useful applications like Mozilla and Konsole (because Pine is still used by
many students), devices like USB-stick and CDROM, were represented by desktop links.
Nobody reported performance problems, although the machine wasn't very fancy:
Processor: P IV with 2.4 GHz
Memory: 1 GB
HDD: 80 GB
Graphics: 2x GeForce2 MX/MX 400, 1x nVidia Quadro FX 500
Keyboards: 2x PS/2 with US layout, 1x USB with DE layout
Mice: 3x USB wheel mouse
Screens: 1x LCD 1024x768, 1x TFT 1600x1200, 1x CRT 1024x768
Network: 10 MBits
Distribution: Debian testing/unstable
kernel: 2.4.25 with backstreet ruby and low latency patches
We want to improve our Conference Internet Corner next year with more terminals, more sockets for
USB-sticks, digicams and maybe a CD burner. And, of course, with a more current KDE version. Whether we should
use KDE's Kiosk Mode is not yet decided; we will test the kiosk mode first to see if it fits our needs.
With Linux, the backstreet ruby patch and KDE and we got a fine, sensational and cheap solution for accessing mails and other online resources at a conference.