Access green II

Access to the green II supercomputer is available through Secure Shell (SSH) to for all users. i.e:

ssh [your-username]


The g2 head-node should only be used as an entry point to the supercomputer, for submitting jobs to the queue nodes, and transferring files (single process only). Compute jobs found to be running directly on the head-node will be removed without notice.

We have a set of interactive nodes (gstar001, gstar002, sstar001, sstar002, and sstar003) that can be used to run short jobs directly, compile code, or test your application. These nodes can be accessed from the g2 head node via ssh too. i.e:

ssh gstar001

Please don’t use these nodes to run long jobs or jobs with big computational requirements. Running such jobs in interactive mode can be done by requesting interactive nodes from the queue. Jobs running on interactive nodes can use up to 80% of the nodes total memory with a maximum of 4 GB of swap.

Client Requirements


A terminal is required to access Green II via Secure Shell (SSH) and issue command line instructions.

Operating System Terminal
Mac Available by default via Applications > Utilities > Terminal
Linux Available by default
Windows The recommended software is Putty

File Transfer

In order to transfer files from and to Green II a ssh-based file transfer utility is required. There are a variety of Options that you can use.

Operating System Terminal
Mac “scp” (secure copy) command can be used via the terminal or use Cyberduck as a GUI alternative
Linux “scp” (secure copy) command can be used via the terminal
Windows The recommended software is WinSCP

As an alternative option, you can use a SFTP Client (e.g FileZilla Client – more details about using the SFTP mode in FileZilla can be found on

X11 Windows Forwarding

If you prefer to use the graphical screen of your application rather than a terminal, the ability to forward a graphical screen from the application back to your home computer is available via X11 Windows Forwarding.

With Linux and MacOS this can be done by login from the command line Secure Shell with the -X option (for X forwarding):

ssh -X [username]

For MacOS you will first need to install XQuartz.

For Windows you will need to install an X11 Server implementation. The following options can be used:

You will need also enable X11 forward from Putty, before connecting, This can be done through connection > SSH > X11 by selecting “Enable X11 Forwarding”.