Re: [LUG] VNC

[Neil Stone <Neil@xxxxxxxxxxxxxx>]

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Simon Robert wrote:
> Hi
> do any of you have experience using vnc? It looks great, you can have 
> lots of PC's, thin clients, whatever running linux gnome/kde/whatever 
> sessions.
>
> I thought that the tricky bit would be configuring it, but not so. With 
> linux 9 the vnc server stuff comes as standard and configuring it all 
> took about 4 minutes. I set it up PC to linux server at the office and 
> all was good.
>
> However out on a client site with a far more powerful machine running as 
> the linux server it runs like a one legged dog!
>
> The problem maybe to do with xwindows, in that the kde desktop just 
> ain't getting the resources and priorities it needs in terms of memory 
> etc. The graphical login screen jumps up nice and fast, after that 
> though you could make and drink a cup of tea between the display of each 
> line of the kde gui. As for the mouse move it from one side of the 
> screen to the other and you can go off for 10 minutes while the 
> graphical pointer catches up with the movement.
>
> It doesn't seem to be a network problem as run it in text mode and it 
> seems to go at normal speed, i.e. do a find or list things. So anyone 
> got any ideas on what to do... ?

I have used the linux vncserver and vncviewer software a fair bit... one 
thing I have found however..

Because of the way VNC works, it can be very intensive when running on a 
high graphics desktop. ie a jpeg for wallpaper, lots of funky effects.. 
the reason is quite simple.

the VNC server sends blocks of data, screen images, to the client top 
down. it also sends a complete screen refresh if there are non native 
colours used.

eg.
 Black desktop colour (#000000) no animation = very fast
 jpeg image desktop with a gradiant border, and lots of animation = very
  slow

Another thing I have found.. and I am not just having a go for the hell 
of it..

The Microsoft TCP/IP stack seems to generate a lot more traffic than the 
Linux tcp/ip stack. why ? who knows.. perhaps it is because Windows was 
never designed to use TCP/IP from the word go where Linux was ?

If you are interested in remote computeing you may want to look in to 
using X in a remote environment, showing a screen from a "server"

If anyone is interested in this, let me know I'll see if I can answer 
any questions.


Neil

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