The utilities Terminal (already installed on Mac) and Chicken are needed to connect to the PBIC Cluster.



Using Terminal to start a vncserver session


Enter the following at the command prompt in the terminal window, with username being your University ADF user name:


Enter your University ADF password when prompted.

Once successfully connected through ssh enter the following at the command prompt to start a VNC session:


You may want to override the default desktop size (the default is 1024x768) to match your local desktop screen or laptop size. If, for example, you wanted a larger screen size of 1280x1024, amend the command as follows:

vncserver -geometry 1280x1024

You may want also want to override the default color depth (16 bits) to be 24 bit color:

vncserver -depth 24

Or you may want to do both at the same time:

vncserver -geometry 1280x1024 -depth 24

Note that you should only run the vncserver command once, the first time you connect to Only if the vncserver session crashes or if the PBIC Cluster is rebooted should you run this command again. If you do already have a vncserver session running, do not try and run another server session. You should get a warning telling you that you already have a session running (and telling you which session number it is). If you do start multiple sessions, the later ones will be killed automatically.

If you have never run the vncserver before you will be prompted twice to set a password. To avoid later confusion it would be sensible to make this password the same as your regular University ADF login password.

When you run the vncserver command it will show the display name and number of the VNC session in the form:

where XX is a one or two digit number. This is the display number of the virtual desktop.

Make a note of the XX number - it is your unique VNC session identifier.

You may now type "exit" to close this SSH session (or click "x" button on top right of window to close the Terminal window). The remote vncserver session you have started will stay running. So long as the remote computer is not rebooted, this virtual session will continue to run until you choose to kill it.


Connecting to your VNC session on PBIC

The following will need to be done each time you connect to

Open another Terminal window as you did earlier and enter the following at the command prompt, with username being your University ADF user name and XX your VNC server session number on PBIC:

ssh -L 

Enter your University ADF password when prompted.

Leave the above terminal running and click on Chicken, the following window will appear:

Enter the following for the entry Host:


Enter your VNC password and click on connect, you should now have an open VNC session on PBIC.


Finishing a VNC session - Leaving the VNC server running

If you wish to close the connection to close only the SSVNC viewer window.

When you reconnect to this VNCServer session again, you only need to connect using SSVNC.

To close the SSVNC window click on the "x" button in the top right hand side of the VNC window.

IMPORTANT - You should not LOG OUT using the system menu "System -> Log Out user". This will leave the session unaccesable and it will then need to be killed (using vncserver -kill as below) and restarted.


Finishing a VNC session - Shutting down the VNC server

Should you not need to keep the session alive then you should stop your vncserver to free up resources for other users. This can be done by using a Terminal window to connect to as above and then typing:

vncserver -kill :XX

where XX is your display number.


Useful VNC commands


vncserver -geometry 1280x1024 Start vncserver with specified display size
vncserver -depth x24 Start vncserver with specified screen colour depth
vncserver :xx Start specified vncserver session number
vncserver -kill :xx End specified session number
vncpasswd Change vncserver password