Getting Started

Most HPC Systems are unix-based environments with shell (commandline) access.

To log in, one usually uses ssh [1] to reach the respective Login Nodes (Computers reserved for the login of users).

IT Center - RWTH Aachen	RRZE - FAU Erlangen	ZIH - TU Dresden
cluster.rz.rwth-aachen.de	cshpc.rrze.fau.de	taurus.hrsk.tu-dresden.de

Once there, the user can interact with the system and run (very small) programs to generally test the system/software.

Schedulers or How-To-Run-Applications-on-a-supercomputer

To run any significant program or workload on a supercomputer, generally schedulers [2] are employed. Except from the above-mentioned Login Nodes there are usually far more Backend Nodes (Computers exclusively reserved for computing). The scheduler decides who gets how many of those for what time.

In order to run your application with that, you have to tell the Scheduler, what your application needs in term of

• time
• compute resources (how many cpus/sockets/nodes)
• memory resources (how much RAM/storage)
• how to actually execute your application

This ususally is done with a Jobscript. When you have this jobscript ready with the help of jobscript-examples, colleagues or the Support, you can submit it to the respective Batch-Scheduler.

IT Center - RWTH Aachen	RRZE - Erlangen	ZIH - Dresden
LSF	SLURM

After this the application is executed when a set of nodes (computers) are allocated the your 'job' by the scheduler. Usually there is (optionally) Email notification on start/finish of jobs.

Modules or How-To-Use-Software-Without-installing-everything-yourself

A lot of applications rely on 3rd party software. The most basic beeing compilers, this software is usually loadable with the module system.