Basic Computing

Computing Access

One of the very first things you’ll need to do is apply for a Fermilab computing account for your experiment. This will give you a services password (for logging into most Fermilab online resources) and a kerberos password which you use to identify your computer to the Fermilab servers you will be logging into. There are detailed instruction of how to ssh into the appropriate virtual machines for your experiment in the SBND and ICARUS pages.

Communicating with the experiment

If you’re a brand new grad student then the whole idea of how a particle physics collaboration works will be a new concept. The structure can seem a little bonkers but the easiest way to start getting to know how it all fits together is coming to meetings and getting to know who people are. All key information and connection details for relevant meetings will be sent out via the various mailing lists.

  • Let’s start by subscribing you to the SBN Young mailing list!
  • Send an email to with no subject and just one line SUBSCRIBE SBN-YOUNG FIRSTNAME LASTNAME
  • The format is then the same for any other lists just replacing SBN-YOUNG with any other list. An (incomplete) list of SBND mailing lists can be found here and TODO ICARUS MAILING LISTS
  • There is also an SBN-wide slack workspace. This is where most day-to-day conversations happen. You should be able to find anyone on the experiment here, there are also channels for different groups within the experiments which you can join (e.g. #sbn-young). Ask your supervisor to add you to this slack workspace.
  • All important documents, including slides from all internal meetings can be found on the docDB, you should be able to access this through Fermilab’s single sign on once you have your services account (see above).


SSH stands for Secure Shell Protocol. We use it for remote login onto Fermilab servers.

The basic command structure is ssh -KXY <FNAL_username>@<experiment_server>

For example: ssh -KXY

Configuration Files

On your local computer, there are configuration files that specify some configurations for connecting to remote servers. There are system-wide and user-specific configuration files, with the user-specific ones taking precedence.

  • /etc/ssh/ssh_config is the system-wide configuration file. This file provides defaults for users, and the user can be changed in per-user configuration files or on the command line.
  • /home/matt/.ssh/config is my local user configuration file on my local computer

A basic configuration (to connect me to dunegpvm13) looks like the following:

  GSSAPIAuthentication yes
  ForwardX11 yes
  ForwardX11Trusted yes
  User mking
  GSSAPIDelegateCredentials yes

This declares the configuration for sshing into the dunegpvm13 machine

  • GSSAPI Authentication is the requirement for kerberos authentication to SSH
  • ForwardX11 allows for the -X option when sshing e.g. ssh -XY This allows for popup windows when sshing
  • User mking specifies that I can ssh onto this host as that user
  • GSSAPIDelegateCredentials passes on your kerberos identity/authentication onto your user on the server.


-X Enables X11 forwarding. “X11 Forwarding is an SSH protocol that enables users to run graphical applications on a remote server and interact with them using their local display and I/O devices.” - source

-Y enables trusted X11 forwarding.

-K Enables GSSAPI-based authentication (Kerberos) and forwarding (delegation) of GSSAPI credentials to the server.

Local Forwarding


Once you’re able to ssh into the fermilab clusters and are working on these machines it is often useful to be able to view windows such as event displays or plots. This can be done by using a VNC, there are some useful instructions for this on an SBND page.

MRB and setting up a basic build of sbndcode/icaruscode