Using the startx script is only one way to start an X session. Linux has the capability to boot directly into an X session, displaying the login prompt in a graphical fashion. The login prompt can be presented by the traditional xdm (X Display Manager) client, the more recent gdm (Gnome Display Manager), or kdm (K Display Manager) clients.
The xdm (X Display Manager) client is used to display a logon screen before running your window manager. It eliminates the need to use the startx script because the X session is started before logging in. To use xdm (as shown in Figure 12.1), you must configure Linux to boot directly to X11.
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