How to Build a Multi-Seat Ubuntu System

By Bob Smith



This article shows how to install Ubuntu from DVDs, how to configure Ubuntu to use multiple video cards for one user, and, finally, how to configure X to have one user per video head. This is a follow-on to an earlier article presented here. The information in the earlier article is still valid and so this article focuses on the installation and initial configuration of Ubuntu.

Both this article and the earlier one are attempts to help Yared Timoteus. Yared runs a computer school in Kibre Mengist in south-central Ethiopia.



We divide the installation of a multi-seat PC into five main steps:
  1. Install the Hardware
  2. Install Ubuntu from DVD
  3. Configure a Single-user Multi-head System
  4. Modify xorg.conf
  5. Modify gdm.conf


Step 1: Install the Hardware

After testing many video cards and even more drivers we have settled on an accelerated, fanless video card using the nVidia MX4000 chipset. While nearing end-of-life, these cards are still available in both AGP and PCI versions.

You need a keyboard and mouse for each seat. Typically the original seat has a PS2 keyboard and mouse, and each additional seat has a USB keyboard and mouse.


Step 2: Install Ubuntu from DVDs

Internet access at Yared's school is limited to an expensive and slow dial-up account. To overcome this limitation we've sent him a six DVD set of Ubuntu 7.04 which we bought from The Linux Store. The procedure given below assumes the reader has no Internet access and is still somewhat new to Linux. High bandwidth, experienced Linux users should skip this step.

Since we are not using the Internet we need to configure Synaptic to look at the DVDs and not at any of the Ubuntu download sites.

We need to tell Synaptic what packages are each of the DVDs. There's a bug in this distribution of Ubuntu 7.04 in that DVDs are mounted under /media/CDROM but Synaptic expects to find them under /cdrom. We can create a link but the system doesn't always mount DVDs under /media/CDROM. It is easier to do register each DVD manually using the steps below.

You can verify that the above steps worked by opening Synaptic. Use System->Administration->Synaptic_Package_Manager. The footer at the bottom of the window should report that something like 21,000 packages are available for installation.

When asked, you might want to apply the updates the system finds on the last DVD. Not that you need them, but the system will keep pestering you to install them.


Step 3: Configure a Single-user Multi-head System

At this point we could refer to the earlier article to configure the system for multi-user use. However Ubuntu can make this a little easier by detecting and configuring the video cards for us. The procedure below describes how to do this.


Step 4: Modify xorg.conf

Most of the system changed needed to build a multi-seat system occur in the xorg.conf file. Here are the steps to modify the file.


Step 5: Modify gdm.conf

The final step in setting up your multi-seat Ubuntu PC is to tell gdm, the graphical login program, about your additional seats.