In UNIX-like systems, GUIs (Graphical User Interfaces) of the programs are rendered trought the X Window System (commonly X or X11).

In the X jargon applications launched by users are called an 'X client' and the application that shows all GUIs on a monitor is called an 'X server'.

X clients connect to X server via network (TCP, port 6000), so they can reside on the same machine or on different machines connected by a network.

On UNIX-like (i.e. Linux)  workstations

UNIX workstations already have an X Server that normally shows output from local applications.

To start an application on a remote host (i.e. a node of the ARCBL cluster) you must:

- Open a terminal inside a graphical session (GNOME, KDE, XFCE etc.)

- Login on the node using ssh with the option '-X'

i.e.: $ssh -X user@arcbl01

- Launch the desired application. The windows will appear on your desktop.

On Windows workstations

On windows you have to install an SSH client and an X server: instructions here

Once connected you can launch the desired application and the X server will show the appication GUI on your desktop.