OAK RIDGE, TN -- Oak Ridge National Laboratory has moved up 21 places to claim the No. 8 spot - and No. 1 in the Southeast -- in the Top500 list of fastest computers in the world. The list, released Thursday, identifies the most powerful commercially available systems and is presented twice per year by authors at the University of Tennessee; the University of Mannheim, Germany; and the Department of Energy's National Energy Research Scientific Computing Center at Lawrence Berkeley National Laboratory. In compiling the list, the authors use the Linpack benchmark, which consists of a dense system of linear equations that allow the user to scale the size of the problem and to optimize the software to achieve the best performance. "This performance does not reflect the overall performance of a given system, as no single number ever can," an explanation posted at the Top500 web site (http://www.top500.org/) notes. "It does, however, reflect the performance of a dedicated system for solving a dense system of linear equations. Since the problem is very regular, the performance achieved is quite high and the performance numbers give a good correction of peak performance." The rating system was introduced by Jack Dongarra, a distinguished professor at UT, and Hans Meuer of the University of Mannheim. This is the 19th compilation, which Dongarra first issued in June 1993. In November 2001, the Department of Energy's ORNL had the 29th fastest computer. ORNL's Cheetah, an IBM Power4 System linking 27 p690 units, achieved 2.3 teraflops, or 2.3 trillion calculations per second. The computer's theoretical speed is 4.5 teraflops. ORNL is on a path to exceed 100 teraflops computing power by about 2006, according to Thomas Zacharia, associate lab director for the Computing and Computational Sciences Directorate. "This is part of an ongoing commitment to Oak Ridge National Laboratory, to the researchers and to the science," Zacharia said. "Without these incredible computers, we simply cannot hope to tackle the challenges our scientists face in climate studies, nanotechnology, genetics research and other disciplines." As further evidence of ORNL's commitment in the area of high-performance computing, Zacharia points to the computational sciences facility, a 300,000-square-foot building under construction at the east end of the laboratory complex. The facility will include 40,000 square feet for the computer center. Also, soon to be under construction is the Joint Institute for Computational Sciences, a state-funded 50,000-square-foot complex to support collaborations between ORNL, UT and other university partners. The new buildings and ever-increasing computing power strengthen ORNL's role as a major resource for DOE's Scientific Discovery Through Advanced Computing (SciDAC) Program, Zacharia said. SciDAC is an integrated program that will help create a new generation of scientific simulation computer programs. The programs will take full advantage of the extraordinary computing capabilities of computers capable of performing trillions of calculations per second to address increasingly complex problems. ORNL's computing power has increased significantly over the past few years. Just two years ago, the laboratory passed the 1 teraflop mark with the IBM RS/6000 supercomputer. In 1995, ORNL had the fastest computer in the world with a speed of 150 gigaFlops, or 150 billion calculations per second. ORNL is a Department of Energy multiprogram research facility managed by UT-Battelle. IBM is a registered trademark of International Business Machines Corp. For more information about IBM research, visit http://www.research.ibm.com