Graphical Applications

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General Graphic Application Comments

There are three ways to connect to Arrow to run graphic applications. These are:

  • Running the NoMachine NX client
  • Running the X2Go client
  • Running X

Running NoMachine and X2Go are the most efficient because they transfer information between the cluster and the client using data compression.
Once connected to the cluster by one of these methods, you can easily test that a graphics connection has been made by entering the following:

enter your password

You should now see a graphic display of a set of eyes that can be moved around using your mouse. If this works, then your graphical application should be installed correctly.

Graphical Applications Using NoMachine NX

To provide for remote use of graphical applications on the cluster, we've installed NoMachine NX on the login hosts. To use it,

  1. Download and install the free NX Client. (Windows users should install the optional font packages.) The NX Client uses SSH behind the scenes;
  2. When you log in the first time, you'll see a window with a number of configuration options. Under "Desktop", choose "Unix", either "KDE" or "GNOME", and the appropriate type of connection you have to the Internet. (Users on the Argonne network should use "LAN".)

You should be able to use interactive GUIs with NX even over a DSL or cable connection. If you have problems, please contact us by clicking to send email or via telephone: 630-252-8224.

Terminating and Disconnecting

When you quit an NX session, you can either terminate it or disconnect from it. Terminating it will close all your running programs. If you discconnect you can reconnect later to the same session.

If you close the NX client window, you'll be given a choice of terminating or disconnecting.


If you want to reconnect to an NX session, you'll have to log in to the same login node on which it was started. To do this, instead of using '' as the server host, specify the login node you want to connect to.


  • You may see the error message "Error activating XKB configuration" when you start a new session. This can be ignored, but if you want to get rid of it, then: from the Applications menu, go to Preferences -> Keyboard, then the Layouts tab, and click Reset to defaults. This should only need to be done once.
  • If the NX client stops working for you, log in with SSH, then try moving the .nx directory in your home directory out of the way:
cd; mv .nx .nx.bak
  • If you get errors similar to this:
Warning: Cannot convert string "-*-courier-medium-r-*-*-*-120-*-*-*-*-iso8859-*" to type FontStruct

you need to install the optional font packages for Windows from NoMachine.

Graphical Applications Using X2Go

X2Go can be installed by following the instructions here.. Instructions are provided for Windows, OSX, and a number of other client OSs. It should be noticed that if you don't already have XQuartz installed on OSX, you will need to do that before installing X2Go. A general X2Go tutorial can be here.

Graphical Applications Using X

xming is a convenient and easy to install X server for Windows. However, if you're doing pre- or post-processing that requires sending a lot of graphics over the network, we recommend NoMachine NX or Z2Go because their compression of the graphics yields a significant speed advantage over X.

To install X on a Mac, refer to this site
Mac uses XQuart to implement X applications and should be installed if not alread installed on your version of OSX. To bring up the window, connect to the cluster by:

ssh -Y