Luca, X windows systems have a display for each desktop environment (KDE, Gnome). All X windows applications look for a display server usually specified by the DISPLAY environment variable then connect to that server via local mechanism or a network socket. Go to a terminal and type "echo $DISPLAY" you will probably get ":0.0" that number specifies what local display to use. If your system is setup for multiple simultaneous X logins (newer distros) each login will have a different xserver and display, the environment variable is how processes launched in each environment know what xserver to connect to. Only one xserver process can use a video card at one time, though they can hand off control from one server to another and the text console typically using the Ctrl+Alt+Fx keys. Until the recent xrandr 1.2 implementation, if an xserver was setup to use two monitors it would create two displays one for each monitor unless the Xinerama option was on. In this case a different desktop environment could be run on each display with a common keyboard and mouse which I think is what you are asking.
If you have two separate video cards, it is possible (though there can be issues) to run a different xserver instance for each card with an independent mouse and keyboard. So one computer with two sets of video, keyboard and mouse could act like two different computers. This can also be done with one dual headed video card using Xephyr, but lacks some features (3D) and will be a little slower. Check out http://www.x.org/wiki/Development/Documentation/Multiseat Why do you need to switch between virtual desktops rapidly from a script? Are you sure this is the right solution to your problem? Quinn _______________________________________________ xorg mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/xorg
