# Computing Guide ## Introduction EPP computing resources include the following: Linux desktop machines Linux interactive machines Batch job service Network file stores Grid computing service Backup service Printing service ## Support EPP computing support is provided by Peter and Alex. Please e-mail Peter in the first instance or drop by our offices on B-floor. Messaging via TEAMS is also fine. ## Accounts User accounts may be requested by filling out [ this Google form](https://docs.google.com/forms/d/11rZI5qLSqeAd2nx7hCuSBE4WtVp2DiIM6L_y02nfVm4/edit). This account is valid on any machine in the cluster. You will receive credentials and instructions to access the cluster. ## Changing passwords If you wish to change your password type the following command on any cluster machine. You will need to pay attention to the prompts and enter your current password then the new password twice. $ passwd ## Desktop machines HEP desktop machines run Alma Linux version 9 and are a general purpose Linux desktop for both physics analysis and admin work. ## Interactive machines There are currently four interactive machines running Alma9 Linux and are well specified with many cores and large memory. Grid User Interface (UI) software is available on these machines and they are mainly used for code development, analysis, and submitting jobs to the batch system and Grid. The machines are: - `lapw.lancs.ac.uk`   (Alma9) - `lapx.lancs.ac.uk`   (Alma9) - `lapy.lancs.ac.uk`   (Alma9) - `lapz.lancs.ac.uk` (Alma9) ## External access to the cluster Secure shell terminal access (ssh) To log into the cluster from outside you will need to use secure shell, either the command "ssh" on a Unix machine or using the program "putty" on a windows machine. ## Personal laptops Personal laptops may be connected to the network but must be registered with the ISS PASS system. Access to HEP resources will then be via ssh to the interactive machines. ## Learning There are copious Linux command line tutorials on the web and the AI chat services have learnt them all. ## Batch system Please check [Quick Start](https://slurm.schedmd.com/quickstart.html) and other docs. ## Grid computing Grid users should apply for an x509 certificate here: http://www.ngs.ac.uk/ukca/certificates ATLAS users can request membership of the ATLAS Virtual Organisation here: https://atlas-auth.web.cern.ch/login      (also request /atlas/uk group) ## ATLAS client tools ATLAS client tools can be setup from cvmfs. It's recommended to add these to your ~/.bashrc file. export ATLAS_LOCAL_ROOT_BASE=/cvmfs/atlas.cern.ch/repo/ATLASLocalRootBase alias setupATLAS='source ${ATLAS_LOCAL_ROOT_BASE}/user/atlasLocalSetup.sh' Then you can run the setup command: $ setupATLAS You may then use the rucio data management commands: $ lsetup rucio --quiet ## Backup It is important to realise that only the /home areas are backed up so if you put critical irreplaceable file on the data disks or anywhere else, you do so at your own risk. The backup is run frequently so we can generally help you recover accidentally deleted files, or old version of files up to 3 months in the past. After this period backups are rotated so we will be unable to help, although older snapshots may be available so please ask. ## Printing ISS-managed printers are available on B-floor in B22 and also at the east end of the corridor. Instructions to setup these printers for Windows, MacOS, and Linux are available on the [ISS web pages](https://print.lancaster.ac.uk). ## Video conferencing We have a various video conference rooms around the department. These are managed by ISS. Most experiments use their own systems such as Zoom so please refer to your experiment's documentation. ## Web Browsing Firefox and chrome are available on the Desktops. ## Editing and development IDE A variety of text editors are available on the linux systems. For example vim, nedit, gedit, pico, vscode and even emacs for the brave. These days people tend to run VSCode on their laptop/desktop and remote access into their linux account. ## Compiling Fortran, c and c++ programs are compiled and linked using gcc. Each experiment will have set ways to manage their code development. ## Text processing Use pdflatex.