Multivnc for XOs(children) and Ubuntu box (teacher)

[Ton van Overbeek]

On Wed, Dec 10, 2008 at 1:28 PM, Arjun Sarwal <arjun at laptop.org> wrote:
>  (Somewhat in continuation with the x11vnc and vncviewer discussion
> thread started here
> http://lists.laptop.org/pipermail/devel/2008-November/021281.html  )
>
> Has anybody tried/gotten multivnc to work ?
>
> I started the multivnc server on my Ubuntu box, and then I start
> multivnc on the client side (on an XO) and it recognizes a multivnc
> server running in the network and attempts to connect to it, but it
> exits with the following information displayed. Log attached below.
>
>  Any help/pointers towards getting this running on XOs, and/or
> otherwise on a set of 2 desktops, as a first step towards getting this
> to run on the XOs - would be helpful.  The instruction manual
> available online is in Chinese and I cant seem to find an English
> version. I will also be pinging to the RealVNC lists too.
>
> Thanks in advance,
> Arjun
>
>
> arjs at arjs-dev:~$ multivnc_client -d 0
> clientID(ok click): arjs
> vncdisplay=0
> 0  -1  -1  -1  -1  -1  -1  -1  -1  -1  > 0
>
> recv-adv 40
> type=8
> length=40
> serverID=teacher
> serverip=10.0.0.5
> serverport=50000
>
> clientadv.client_ID: arjs
> type=10, flag=1
> switch : rfbAllowAdv
> vncdisplay=0
> vncconfig -display :0 -connect 10.0.0.5:50000 > /dev/null 2>&1; echo -n $?
> vncconnect -display :0 10.0.0.5:50000 > /dev/null 2>&1; echo -n $?
> vnc4config -display :0 -connect 10.0.0.5:50000 > /dev/null 2>&1; echo -n $?
> print_popen : 127
> print_popen : 127
> print_popen : 127
> print_popen : 127
> print_popen : 127
> print_popen : 127
> print_popen : 127
> print_popen : 127
> print_popen : 127
> 3
> arjs at arjs-dev:~$
>

Arjun,

I have started digging through the source of multiVNC and also used
Google translate to try to
understand the manual in Japanese.
In multiVNX the teacher runs the multivnc server and has a summary
screen with all the students
display (max 16 on a single tab). For this to work each student
(multivnc client) also has to run a
vnc server on X display 0. They do not use the original Xvnc (which
creates a separate X display) but
a module in the X server to provide the VNC server functionality for display 0.
What I see in your log is the multivnc client trying to configure the
VNC server on the same machine
and failing. It does this by trying 3 times the 3 flavors of
vncconfig, but getting a return code
of 127 from the shell executing each command (the 9 "print_popen: 127").
My guess is that there is no VNC server running on arjs.
If the only thing you want is to distribute the teachers screen to all
the students then this
might be overkill. Your original x11vnc on the teachers Ubuntu based
computer might work
better. I have done the opposite (x11vnc on the XO, displaying on
Windows XP) and this
works very well, almost instantaneous screen update.

multiVNC certainly looks applicabe in the OLPC environment. Only the
teachers computer has
to have a larger screen than the XO provides. I'll try to understand
better how it is supposed
to work.

Ton van Overbeek