The Vienna Scientific Cluster (VSC) has been designed to satisfy the demand for High Performance Computing of the University of Vienna (UNI), the Vienna University of Technology (TU), the University of Natural Resources and Applied Life Sciences Vienna (BOKU), the Graz University of Technology (TU Graz), and the University of Innsbruck. Access to the VSC is granted on the basis of peer-reviewed projets which, beside scientific excellence, can demonstrate the need for extremely large computational resources. Currently two systems are in the pool: VSC-1 and VSC-2.