MATH does not have servers dedicated to just faculty and students at MATH. We had at one point, but they were only seldomly used. So instead AUIT provides some general purpose Linux servers all students and faculty at AU kan use. See below.

If you need to run simulation, a large calculation or something similar on a Linux server you can use the server

• linuxapp.au.dk

This is actually several servers (see further explanation below). The server(s) are only accessible via SSH. To login you use your auAUID as your username and your normal AU password, that is

• ssh -l auAUID linuxapp.au.dk

(other SSH option may also be relevant such as -X and -Y).

If you use Windows, we recommend using the free tool Moba Xterm which includes SSH and other tools needed to communication with a Linux server from Windows (Moba Xterm also include a simple file transfer tool). On Mac and Linux SSH is already available, though you will probably need to install XQuartz on your Mac if you want to open a graphical interface from the Linux server and display it on your Mac.

On the linuxapp servers you will find tool like MatLab, Mathematica, SAS, R, python, CPLEX etc. If it is free and available for Ubuntu, you can probably get the IT department to install it. Such request needs to be sent to the helpdesk, this is also the case if you know there are available updates to the tools listed earlier. Note that the MATH department does not have admin access to these servers.

Behind linuxapp.au.dk is actually several servers, linuxapp.au.dk is just a front end/load balancer. As of Jan-2020 it is 3 virtualised serveres running on Intel Xeon each with 64Gb of RAM. They are not super computers, but generally more capable than your average desktop PC or laptop.

Note that the servers does not have dedicated GPUs!

Other noteworthy things you need to know

• Since linuxapp.au.dk is a frontend/load balancer, you have no control over which server you end up with. It will be one of linuxapp01, linuxapp02 or linuxapp03
• Linuxapp01,-02,-03 are NOT accessible from the outside, thus you always have to access them through linuxapp.au.dk
• Linuxapp0x share filsystems (as long as you place your files in your storage area, /home/auAUID), thus for file transfer it does not matter which server you land on.
• Make sure to read the SSH Welcome Message when you log in, it contains several hints as to how one goes from say Linuxapp01 to Linuxapp03 or ask the servers which processes you have running on the three servers (in case you forgot which of the three servers your simulation is running on).
  
  Jump to another: ssh linuxapp0x
  See what processes you have running: ps -fu $USER
  Ask another server if you have something running on it: ssh linuxapp02 ps -fu $USER
• If you are on Eduroam or want to use linuxapp.au.dk from home, you will need to use VPN (the general AU VPN "AU Access" is enough, thus all students can access linuxapp via VPN), see au.dk/vpn for more information
• One-way communication: All communications with linuxapp.au.dk needs to start from your computer. You cannot  "put" a file from linuxapp.au.dk onto your computer, you need to "pull" it it from your computer instead.

A few things that are probably useful to look into as a new Linux user

• Learn to use the commandline (basic folder navigation, move/copy files, inline editing a file, I tend to use nano for simple exits)
• If you need to run lengthy simulations/calculations (that does not run via a graphical interface) it is a good idea to learn to use tmux (terminal multiplexer). This is a sort of "remote desktop" for command lines. If you start your simulation inside tmux, then tmux enables you to leave the tmux session with the simulation still running inside it!! Logout of linuxapp, then come back later (to the same linuxapp0x-server) and then resume the tmux session where the simulation is running. Without tmux you often need to stay logged in to LinuxApp for the duration of the simulation.
• Learn to run MatLab, R or SAS simulations/calculations without using a graphical interface (say Rstudio), then you can easily use it with tmux (mentioned above) and can just start your simulation, log out can come back to it later.
• A file transfer program like FileZilla can be useful for transferring files to and from LinuxApp.
• Windows users are recommended to use Moba Xterm (its free).

Otherwise feel free to come and ask. Just remember that the linuxapp are NOT dedicated MATH servers they are maintained by AUIT (their Linux department).