Setting up the X Terminals

Setting up the 486 PCs as graphical X terminals was fairly straightforward, consisting of just a few steps:

1. Installing a minimal Debian Linux system on each PC
2. Configuring each PC to start up X and query an XDM server to get a list of hosts to connect to.
3. Configuring one or more XDM servers to provide "chooser" services to the X terminals.
4. Configuring XDM and the chooser to be more aesthetically pleasing and useful.

I'll discuss each of these steps in turn.

Installing a minimal Linux system:

Since our existing Linux systems run Debian Linux we chose to use it for these PCs as well.

On each system, we installed just the basic Debian system from floppy, which provides a very bare-bones Linux system with networking support. No user accounts were created, since none are needed (since no users actually log into the machine itself). A complete list of installed packages necessary to run the X server is listed here.

Next, Debian packages of XFree86 3.3 were loaded on each system. We loaded the base X11 libraries, the X extensions, the S3 X server (since the PS/Valuepoints have 2-meg S3-based video card), and all the X11R6 fonts.

Finally, we installed a few additional packages for convenience, including basic networking utilities (netbase), ssh (to allow use to remotely log in through a secure channel), and nvi since the systems staff here doesn't like the default Debian text editor.

Configuring each PC to start up X:

The first step was configuring X to run locally on each PC. An XF86Config file was created for the machines using the standard 'xf86config' utility, with a couple of considerations:

• The "Emulate3Buttons" option was enabled, since the mice that came with the machines are only 2-button mice.
• While the 2-meg S3 card in the Valuepoints is capable of up to 1152x900x16bit resolution, we chose to run 1024x768x8bit, since it runs at a more comfortable refresh rate, better viewability on the 15-inch IBM monitors, and provides better compatibility with local applications than 16-bit color.
• For added security, "DontZap" is specified so that users cannot inadvertently kill the X server.
• We added additional SGI-defined colors to /usr/lib/X11/rgb.txt so that the X-stations could talk to our SGIs without errors.
• You may wish to set up a font server somewhere.

Once we were satisfied with the configuration of the X server, we then tested if it could connect to a workstation running xdm (xdmserver in this example):

X -quiet -query xdmserver

So, we now know everything is basically working. If we just want the PC to talk to a single workstation, then we are basically done. The only remaining step is to make sure that X is started upon bootup. We can do this with a script in /etc/init.d/xterm.

On a Debian system, we install it with 'update-rc.d xterm defaults 99'. (The procedure for Redhat, Slackware, etc., is similar). We then reboot the machine to make sure it starts X upon boot.