MDM stands for "multiseat display manager". Despite its name, mdm is actually a wrapper on the real display manager. It is used to configure multiseat environments, allowing users to change a normal machine into a multiseat machine by just installing a package.
There are many ways to configure multiseat environments. Some people use nested X servers, while others use multiple instances of the X server or maybe VNC or directfb or anything else. Also, combined with these solutions people might want to use GDM, KDM, XDM, remote X without display managers or many others. The goal of the mdm package is to be generic enough to be able to be used in any solution.
mdm consists of two disctinct parts: the core, simply called mdm, which is the solution-independent code, and the multiseat mode, which is the solution-dependent code. The core is installed by the mdm package and the other multiseat modes are installed by the other packages (like mdm-xephyr-gdm, which combines Xephyr and GDM). There are also some default modes inside the mdm package, like the xephyr-xdmcp, which just starts X servers connected to remote xdmcp servers. Modes that have extra dependencies are provided by other packages.
The core package is responsible for detecting input devices, video cards, creating xorg.conf, associating seats with devices and then calling the modes
The modes are actually bash scripts that define some specific functions that are called to start the displays used by the seats. They are usually located in /usr/share/mdm/modes. To change between modes, it is necessary to edit the MULTISEAT_MODE variable inside the mdm configuration file.
There are 3 ways to use mdm. You can:
- install the mdm package from our repositories;
- compile and install mdm from git
- or download our Live-CD and boot it in your machine.
You'll have to install the main mdm package, the package for the multiseat mode you want to use and then edit the mdm configuration file to use the right mode and change other preferences.