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The RRZK's central computers have powerful processing capability and larger and more secure storage space than most personal computers. They are particularly suitable for running more demanding software such as advanced graphics, data analysis packages, databases and user programs.
The ZAIK/RRZK operates six central HPC (High Performance Computing)-Servers:

• CLIOT (Sun Opteron Cluster)

  Peak Performance >1,1 Tflops Processors 258 Memory 772 GB Operating System Red Hat EL 3.0 + Rocks

• ALTIX1 (SGI Altix 3700 Bx2)

  Processors 128 Memory 512 GB Operating System Red Hat EL 3.0

Information about the use of these systems can be found in Arbeiten auf den Zentralen Rechnern - Unix-Serversysteme (German). In particular you will find there descriptions of specific local features.

Formal Prerequisites

To use one of the compute servers you need a special account. You can find out how to apply for such an account through the Uni-Account web page. The registration procedure is partly automated, in the worst case you will need to complete a user registration form (Pdf-file) and return it to the users office.
Once your account has been set up you should consult your department's designated contact person among the scientific staff of RRZK and provide them with a brief outline of your application. This will also give you the opportunity to discuss your special requirements concerning compute time, disk space, and software environment. During your project the RRZK contact person will help you if questions or problems arise. Furthermore, at the start of your project he will take care that you join some important mailing lists such as "hpc-aktuell" which will provide you with news and information about the RRZK high performance computers. Other interesting lists are "aktuell" and "betrieb-aktuell" -- if you wish to join, leave or simply enquire about any list you can use the Mailman system.

You will find all mailing lists maintained by ZAIK/RRZK on our web pages:
www.uni-koeln.de/rrzk/maillist/liste.html.
An alternative means of obtaining current news about the University's computer networks, systems, hardware and software are the ZAIK/RRZK web pages:
www.uni-koeln.de/aktuell/betrieb.

Batch Jobs

To enable a better load sharing on the UNIX compute servers the batch system Sun Grid Engine (Codine, german website) has been installed. All jobs requiring more than one hour of CPU time must be submitted as batch jobs.
If your job produces large output files we recommend starting it from the directory /scratch. /scratch offers you large disc space, and every user is allowed to create his own subdirectory to store data in /scratch. However, only intermediate results should be stored there, and you are advised to move the final results of your computation into your home directory or into a special /project subdirectory for large amounts of data.

Project Directories

Since April 2004, ZAIK/RRZK provides a SAN (Storage Area Network) for providing users with disk space on the central computers, which now permits us to provide users with project directories of several TB. By using NFS and symbolic links, users are guaranteed a uniform view onto data stored in /projects// from any of the central servers. For installation of a new project directory please ask your RRZK contact person. For long-term storage or back-up of your data use our central file archiving system TSM (Tivoli Storage Manager, german website).

Software

ZAIK/RRZK supplies a wide range of software to cover all the University's routine and department specific needs (e.g. mathematics, chemistry, genetics software systems). A complete list of pre-installed software can be found via our software page.

Development of user software

When you write your own C or Fortran programs to be run on the RRZK compute server platforms you can influence the performance in various ways (compiler options, use of libraries, and much more...). RRZK provides detailed information about writing and optimising parallel programs on the (german) web page "Die Durchführung von Projekten auf den Compute Servern".
You may want to ask your RRZK contact person for assistance. He will be able to give you advice concerning your program options and help you to find appropriate English language information.