X-terminal attaching to an existing session ?

[garyng]

Hi,

With a slight modification, Knoppix can be a very handy XServer(X-Terminal) solution.

What I would like to know is if the X11 system support the usage of reattaching previous sessions like the wonder screen utility in text mode. If that can be done, I would be able to go to any workstation, boot knoppix and re-attach to an previously detached but still running desktop on a server.

I know that x11vnc can do this but that would mean running multiple copy of X11 server on the server which can use lots of resource on the server.

[Dave_Bechtel]

--Try using VNC, and monitor the situation with "top". Running Xrealvnc doesn't use a whole lot of resources from what I've seen, but YMMV.


Hi,

With a slight modification, Knoppix can be a very handy XServer(X-Terminal) solution.

What I would like to know is if the X11 system support the usage of reattaching previous sessions like the wonder screen utility in text mode. If that can be done, I would be able to go to any workstation, boot knoppix and re-attach to an previously detached but still running desktop on a server.

I know that x11vnc can do this but that would mean running multiple copy of X11 server on the server which can use lots of resource on the server.

[garyng]

thanks. VNC is actually a more suitable solution for me but just that the multiple xserver(which is what xvncserver does) on the server scares me a bit in terms of resource. Didn't test it though.

However, it seems that VNC is slower than X, at least in my limited test situation on a local 100Mbps network, especially when I hold the scrollbar and drag. This is understandable as VNC need to sort of redraw the screen in a pixel by pixel for each small movement. The difference is though quite noticeable.

[Dave_Bechtel]

--VNC gets more responsive when you:
o Load a more lightweight Windowmanager (such as Icewm)

o Use SSH with portforwarding and compression.

Example: Put this in ~/.vnc/Xsession:


# initialize variables for use by all session scripts

OPTIONFILE=/etc/X11/Xsession.options

SYSMODMAP=/etc/X11/Xmodmap
USRMODMAP=$HOME/.Xmodmap
SYSRESOURCES=/etc/X11/Xresources
USRRESOURCES=$HOME/.Xresources

SYSSESSIONDIR=/etc/X11/Xsession.d
STARTUP=$HOME/.xsession
ALTSTARTUP=$HOME/.Xsession
ERRFILE=$HOME/.xsession-errors

#xinit /usr/bin/sawfish

xrdb

rxvt &
# -display :3 &
/usr/bin/sawfish &


--Here is an example script that I use to start VNC on the server side:

BEGIN remotex


#!/bin/sh

#vncserver -cc 3 &
# cc 3 == pseudocolor visual

vncserver :2 -geometry 900x700
# -cc 3 -geometry 1024x768 -fp /usr/lib/X11/fonts/misc/,/usr/lib/X11/fonts/75dpi/ -fn -misc-fixed-bold-r-normal--13-100-100-100-c-70-iso8859-1
# Use font -misc-fixed-bold-r-normal--13-100-100-100-c-70-iso8859-1

# Connect using vncviewer p233:5902 || http://p233:5802
#vncserver -kill :2

# if ssh -2 -C -L 5992:p233:5902 p233
# THEN vncviewer localhost:5992


--Here is how to port-forward with compression (Note the VNC server hostname on my network is p233.)

BEGIN ssh-vncserver


#!/bin/bash

ssh -2 -C -X -c blowfish \
-l dave \
-L 5992:p233:5902 \
10.0.0.2 $*


--The above code forwards port 5902 on the vnc server to port 5992 on the client box, with compression. Connect the VNC viewer to localhost:5992 after starting the remote X session, and it will use the compressed port connection.

--You can also play with the VNC viewer's Options and experiment with different ways to re-draw the screen. :)

--Note that you will have to assign a password to the VNC session the first time you run it... Best of luck.


thanks. VNC is actually a more suitable solution for me but just that the multiple xserver(which is what xvncserver does) on the server scares me a bit in terms of resource. Didn't test it though.

However, it seems that VNC is slower than X, at least in my limited test situation on a local 100Mbps network, especially when I hold the scrollbar and drag. This is understandable as VNC need to sort of redraw the screen in a pixel by pixel for each small movement. The difference is though quite noticeable.

[garyng]

thanks, I was running vnc over SSH(compression on) and the wm is fluxbox. Not that it is slow in normal operation(perfectly fine) but if I am in firefox browsing and use the scrollbar, the speed difference(comparing with X) is quite noticeable.

PS, the machine I am VNC in is a XBOX.