Login and logout

Remote login

A remote login is a connection between your personal computer and another computer via a network (normally the internet). Your computer is local and the other computer is remote. In the case of Melbourne Bioinformatics (formerly VLSCI), the remote system will be one of our supercomputers. A remote log in allows you to type commands into your computer and have them execute on the remote system, with the results displayed on your screen.

Connection between local and remote computers

There are a few ways to remotely login to a Unix computer, but at Melbourne Bioinformatics we require you to use the Secure Shell (ssh). It is secure because it encrypts all the data sent between the connected computers, which, amongst other things, prevents eavesdroppers from seeing your password in plain text.

In order to use ssh you must run an ssh client on your computer and tell it the hostname of the remote computer. These are the hostnames of the supercomputers at Melbourne Bioinformatics:

Barcoo and Snowy are x86 clusters. More information about these machines is available.

There are a variety of ssh clients available depending on which operating system you use. We show how to use ssh clients on Windows, OS X and Linux below.

SSH login from Windows

On Microsoft Windows we recommend that you use an ssh client called "PuTTY" (putty.exe), which can be downloaded from this web page:

http://www.chiark.greenend.org.uk/~sgtatham/putty/download.html

Documentation for using PuTTY is here:

http://www.chiark.greenend.org.uk/~sgtatham/putty/docs.html

When you start PuTTY you should see a window which looks something like this:

Putty Configuration Window

To connect to one of the computers at Melbourne Bioinformatics you should enter its hostname into the box entitled "Host Name (or IP address)", then click on the Open button. All of the settings should remain the same as they were when PuTTY started (which should be the same as they are in the picture above).

In some circumstances you will be presented with a window entitled PuTTY Security Alert. It will say something along the lines of "The server’s host key is not cached in the registry". This is nothing to worry about, and you should agree to continue (by clicking on Yes). You usually see this message the first time you try to connect to a particular remote computer.

If all goes well, a terminal window will open, showing a prompt with the text login as:. An example terminal window is shown below. You should type your Melbourne Bioinformatics username and press enter. After entering your username you will be prompted for your password. Assuming you type the correct username and password the system should then display a welcome message, and then present you with a Unix prompt. If you get this far then you are ready to start entering Unix commands and thus begin using the remote computer.

Putty terminal window

SSH login from Mac OS X and Linux

Both Mac OS X and Linux come with a version of ssh (called OpenSSH) that can be used from the command line. To use OpenSSH you must first start a terminal program on your computer. On OS X the standard terminal is called Terminal. It is installed by default and you can find it in the Utilities folder (/Applications/Utilities). On Linux there are many popular terminal programs including: xterm, gnome-terminal and konsole. (If you aren’t sure, then xterm is a good default.) When you’ve started the terminal you should see a command prompt. To log into Snowy, for example, type this command at the prompt and press return (where the word username is replaced with your Melbourne Bioinformatics username):

ssh username@snowy.melbournebioinformatics.org.au

The same procedure works for barcoo or any other machine where you have an account.

You may be presented with a message along the lines of:

The authenticity of host 'snowy.melbournebioinformatics.org.au (128.250.108.4)' can't be established.

...

Are you sure you want to continue connecting (yes/no)?

Although you should never ignore a warning, this particular one is nothing to be concerned about; type yes and then press enter. If all goes well you will be asked to enter your password. Assuming you type the correct username and password the system should then display a welcome message, and then present you with a Unix prompt. If you get this far then you are ready to start entering Unix commands and thus begin using the remote computer.

Logout

When you have finished using the remote computer you can terminate your connection by typing logout or exit, or just quit your ssh client.