To have two Xorg in two Ubuntu's run levels

Question

Ubuntu support by default only one X at run levels. I would like to have two Xs: one for Ion3 and for Gnome, in two diffferent run levels. This means that I need to change the source code of Ubuntu somehow and somewhere.

It may be possible to use X11 in one run level and Xorg on another run level without modifying the source code. However, my friend says that this is not possible.

How would you change Ubuntu's source code to enable two Xs in two different run levels?

Answer 1

I solved the problem by reading the manuals "Xorg" and "xstart" and then find out the following command

 startx -- :1

Answer 2

You can switch window managers right at the xdm / gdm / kdm / ... login screen. Just apt-get install both ion3 and gnome and the switch at login.