x0vnc server on XO

Zvi Devir zdevir at technion.ac.il
Wed Apr 18 06:11:18 EDT 2007

Hi All,

I've just gave two nice presentations of the XO machine at the Haifa
Linux Club and at Google Haifa/Israel. I decided it will be more
interesting to run the presentation slides from the XO machine itself.
It took the audience some time to realize that, which added magic to the
lecture. Since the XO machine was literally with no strings attached, it
was really a wireless presentation ;)

The trick is to install RealVNC, and run x0vncserver on the XO machine.
A second machine, with a proper VGA port, is connected to the same Wifi
network, and is running a vncviewer that clones the XO display.

Here are the details for those who are interested.
1. Fetch the vnc-server rpm (I've used vnc-server-4.1.2-9.fc6.1386.rpm),
    and install it (--nodeps).
2. Create a password file using vncpasswd.

Before the presentation,
3. Open a developer console.
4. Run the x0vnceserver *nicely* from the developer terminal (as the
server should clones the current display). I was using the following
    nice -19 x0vncserver PasswordFile=~olpc/.vnc/passwd & ; disown
It is possible to run the x0vncserver in "viewing only" mode by
providing the following additional options
    AcceptPointerEvents=0 AcceptKeyEvents=0
I simply created a small script file for that.
5. Check your current IP address (ifconfig eth0).
6. Close the console.

7. In the other machine, run the vnc client.
    vncviewer 192.168.xxx.xxx FullScreen=1 ViewOnly=1
(replace the 192.168.xxx.xxx with your XO IP address).

However, running the vnc server took almost 100% CPU, for no apparent
reason. Therefore, it must be run very very nicely (nice +19), since
otherwise nothing else can be executed without the watchdog starting to
bark. I don't know if it is a x0vncserver bug, or some problems with
Sugar that send some messages all the time.

    Zvi Devir

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