If you are using Linux or Mac OS X then you can start an X session by starting a session with ssh -XY

Mac OS X Important Note for X11

Apple have decided not to include an X11 client by default with it's latest version of OS (Mountain Lion) If you want to use an application in a way which requires X11 (Graphical User Interface) then, please see the following page, which details installing XQuartz

If you are using PuTTY, or another SSH client to connect to HPC then you will need an Xserver running in order to display graphics.  You will also need to either have your DISPLAY variable set, or tunnel X11 traffic over your SSH connection, as detailed in the Connecting to HPC tutorial.

Using Xming

Xming is a free Windows X Server that can be downloaded from the following link. You will need to download the Xming and the Xming-fonts packages. There are installation instructions on the webpage, but the default installation setting will work fine.

Configuring and Running Xming

Once you have installed Xming, run Xlaunch from the start menu and accept the default values.  The default values are :

  • Multiple windows / Display number 0
  • Start no client
  • Clipboard ticked

If you "Save configuration" and save the created ".launch" file to your desktop, you should have an Xlaunch icon on your desktop.  You can double click on the icon, which should invoke Windows firewall to prompt you to "allow" access, click "allow". The firewall prompting will only happen on first launch.

Once Xming has launched correctly, there will be an icon in the system tray (near the clock).  Xming doesn't start with a visible window.

Testing X Server 

Assuming that you have configured PuTTy correctly, as detailed on the Connecting to HPC page, then once connected you should be able to run "xterm" from the PuTTy terminal and verify that a new window pops up, as shown below.