Japan's K Computer and China's Tianhe-1A took the top two spots, but four Department of Energy systems and one run by NASA made the top 10 of a biannual ranking of the top 500 high-performance-computing systems.
Slideshow: Government's 10 Most Powerful Supercomputers
U.S. supercomputers run by the federal government comprised five of the top 10 most powerful in the world, according to the latest list of the world's top 500 supercomputers.
Four systems run by the Department of Energy and one managed by NASA were the top among the 256 U.S. high-performance computing (HPC) systems that made the TOP500 list, many of them run by the federal government.
Several top super-computer researchers compile the list--Hans Meuer of the University of Mannheim, Germany; Erich Strohmaier and Horst Simon of NERSC/Lawrence Berkeley National Laboratory; and Jack Dongarra of the University of Tennessee in Knoxville.
Supercomputers on the biannual list are ranked by how quickly they can run calculations according to Linpack, a benchmark application developed to solve a dense system of linear equations.
A Japanese supercomputer called the K Computer and manufactured by Fujitsu solidly held the top position on the list. With a performance of 8.2 petaflops per second, it performs at three times the speed of its nearest competitor, a Chinese supercomputer performing at 2.6 petaflops per second that K knocked from its previous position at the top.
The DOE's Cray supercomputer at the Oak Ridge National Laboratory--known as "Jaguar"--came in third place, with a performance of 1.75 petaflops per second.
Rounding out the top five U.S. supercomputers in the list's top 10 are a DOE Cray computer called Cielo at No. 6; an SGI system called Pleiades at the NASA Ames Research Center at No. 7; a DOE Cray system called Hopper at No. 8; and a DOE IBM system called Roadrunner at No. 10.
Overall, the U.S. had the largest number of systems on the list, followed by Europe with 125 systems and Asia with 103 systems. In Europe, Germany, the United Kingdom, and France made the strongest showing; not surprisingly in Asia, the countries with the top two supercomputers on the list--Japan and China--are the dominant in the region.
The list also shows supercomputer speeds picking up. All of the systems in the top 10 for the first time achieved petaflop performance, the current gold standard for HPC systems and the only systems on the list to achieve that kind of performance. "Flop" stands for floating-point operations per second, and a petaflop computer can perform a thousand trillion flops.
The federal government uses supercomputers for a range of high-computational work, such as climate change research; Department of Defense testing and evaluation; and 3D modeling used to track severe weather and, more recently, to aid researchers cleaning up the Deepwater Horizon oil spill in the Gulf of Mexico.
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