XDM

Last updated -[Wed May 21 08:34:33 1997 by cxh]-

Places to go

  • xdm man page.
  • SunSoft's XDM faq

  • XDM overview

    The X Display Manager (xdm) manages remote displays, allowing users to log in and run X11 in a more friendly fashion than just starting X from a prompt.

    Locally, we use xdm on the Wang room Sparcstation, wang.eecs.berkeley.edu


    Wang Room User notes

    Keybindings in the login window

    The first window that comes up is the chooser window, the second window that comes up is the login in window.

    If the machine that you connect to is running xdm from sww, then you should be able to use Control-R to abort the current login session, and get back to the chooser window.

    A failsafe session is a session that has just an xterm, your .xsession file is not accessed. Using a failsafe session is useful if your .xsession file is horribly mangled.

    To start a failsafe session, you should also be able to hit either F1 or Control-Return after typing your password.


    Wang Room Sysadmin notes

    Startup

    wang.eecs starts xdm at boot time. The script /etc/init.d/xdm-setup is called from /etc/rc3.d

    To start and stop xdm and the X server, use /etc/init.d/xdm-setup start or /etc/init.d/xdm-setup stop

    Layout

    wang.eecs is running a wierd installation of xdm, where we get a chooser window, even though we are sitting at the console. This allows users who don't have accounts on wang.eecs to choose a host to connect to.

    The wang specific files are in /etc/xdm on wang. We've made these files local so that anyone who has root on wang can modified them

  • xdm-config Configuration options for xdm. /etc/init.d/xdm-setup calls xdm and passes xdm-config as the config file option.
  • Xaccess.console List of what machines xdm looks for to add to the chooser window. The line that contains the string *.Berkeley.EDU CHOOSER is the line that actually lists the hosts. Xaccess.console says: # Keep the line below alphabetical, and shorter than 256 chars # (3 80 char lines = 240 chars). If the line is longer than 256 chars, # xdm won't bring up the chooser # Also don't include hosts on the 240 net, such as hera, since we are # broadcasting on the 240 anyway. # 240 hosts: hera # hosts not running xdm: cascades everglades ic nima parker zabriskie *.Berkeley.EDU CHOOSER argon bsac canyonlands cory crown crissy diva eclair glacier hammerhead haiku ic nima nitride paleale po radon riovista resonance robotics shadow swordfish tilden tin waddel BROADCAST If you need to add a host to the list, this is where to do it. However, be sure to observe the 256 character limit. To test your changes, either reboot do /etc/init.d/xdm-setup stop; /etc/init.d/xdm-setup start
  • chooser A simple shell script that sets the background of the initial root window and then starts chooser.bin, which brings up the list of hosts accepting xdm connections
  • ucseal.xbm The background brought up by the chooser.
  • Xsetup_0 A simple shell script that sets the background when we connect to wang.eecs and then starts up xconsole
  • Ptolemy.xbm The background brought up when we connect to wang.eecs.
  • Debugging hints

  • Debugging while trying to use the machine you are debugging is madness. Two machines saves a lot of time. In the wang room, you can sit in the back room and use the mac and see both screens.
  • The DisplayManager.debugLevel value in the xdm config file is really useful. You may also want to start xdm from the shell with the -debug flag
  • The Sun Newsgroup archives can be useful.
  • If you are having problems with xdm, you can try and run the 'failsafe' session. Type your login name and password, but instead of hitting 'Return' at the end of your password, hit the 'F1' key. If 'F1' does not work, then you can try Control-Return (Hold the Control key as you depress the Return Key). This should bring up a simple xterm session. You should be able to start an editor and fix up your .xsession file.
  • If xdm does not start up a session, check that your .xsession file is executable.
  • The initial user defaults often save output to a file called .xlog or .xsession-errors. Check your home directory for information in these files. You could also try looking at /var/adm/xdm-errors on the machine that you tried to connect to.