The heterogeneous nature of high performance computing requires inexhaustible knowledge about the hardware, software, and interconnects that comprise such machines. Thus, such a myriad of architectures presents unique challenges that require testing and development of applications that are often quite unique to the platform on which they reside. For this reason, it is imperative that we have access to a very wide range of computing resources in order to conduct our cutting-edge research. On this front, we have multiple, heterogeneous systems in-house. But we also have access to multiple architectures around the country due in large part to our many collaborators and partners. Locally, we maintain systems ranging from individual desktops to large, networked clusters. We've even built and experimented on a cluster of Sony Playstations. Below is a summary of the many computing resources used by ICL.

The following are the local systems that we use on a daily basis to test our work:

• 64 node Intel EM64T cluster connected with Myrinet 2000
• 64 node AMD Opteron cluster connected with Myrinet 2000
• 24 node AMD Opteron cluster connected with Silverstorm, Mellanox, and Myricom
• 16 node Intel Xeon connected with Gigabit Ethernet
• 8 node Intel Core2 Duo cluster with Gigabit Ethernet
• Intel Itanium clusters

In addition to these resources, we have access to several server class machines and several HPC clusters in other departments. These clusters consist of multiple architectures and comprise over 100 machines with various architectures. All of our clusters are arranged in the classic Beowulf configuration in which machines are connected by low latency, high-speed network switches.

Furthermore, exclusive access to many remote resources, some that are regularly found in the Top500 list of the worldís fastest supercomputers, help keep us at the forefront of enabling technology research. The recent modernization of the DOE’s Center for Computational Sciences, just 30 minutes away at the Oak Ridge National Laboratory (ORNL), has enabled us to leverage our ORNL collaborations to take advantage of what is becoming the world’s fastest scientific computing facility. The following are some of the remote systems and architectures that we utilize:

• Cray X1, X1E, XT3, and XT4
• HP XC system
• IBM Power 4, 4+, 5, 5+, 6, Cluster 1600, BlueGene/L, and the Cell
• Several large (256+ proc) Linux Clusters
• SGI Altix