High-performance computers, also called supercomputers or high-end computers, by every definition describes machines that employ massively parallel processing to address scientific and engineering challenges.  "Massively parallel processing" splits up a task or problem and parcels it out to multiple processors that work simultaneously but in concert to quickly supply results. High-performance computers link hundreds or thousands of processors - the computer chips that perform most calculations - in massively parallel configurations.  Some of the processors in high-performance computers are specially designed for their purpose.  In others, the processors are similar to the commercially available ones found in home computers, but they're linked by custom-made hardware and software that lets them work together quickly and efficiently.

High-performance computers carry out billions or even trillions of calculations each second - powerful enough to simulate complex physical, biological and chemical phenomena.  They help scientists understand these processes at unprecedented levels - from individual atoms for nanoscale engineering to the entire planet for global climate studies. High-performance computers also are powerful enough to provide insight into systems and process by simulating them with great detail over relatively long times.

The primary facilities funded and managed by ASCR are listed below.

• Leadership Computing Facility - Oak Ridge
  The Leadership Computing Facility (LCF) at Oak Ridge National Laboratory is building the world's most powerful unclassified scientific research supercomputer to provide computational science researchers with an environment for new discoveries.
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• Leadership Computing Facility - Argonne
  Argonne Leadership Computing Facility provides the computational science community with a world-leading computing capability dedicated to breakthrough science and engineering.  The ALCF provides resources that make computationally intensive projects of the largest scales possible.
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• INCITE
  The Innovative & Novel Computational Impact on Theory and Experiment (INCITE) program was conceived specifically to seek out computationally intensive, large-scale research projects with the potential to significantly advance key areas in science and engineering.
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• NERSC
  The National Energy Research Scientific Computing Center (NERSC) is a supercomputing center funded and maintained by ASCR at the Lawrence Berkeley National Laboratory to support basic scientific research.
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• ESnet
  Energy Sciences Network (ESnet) provides an interoperable, highly capable and reliable communications infrastructure and a spectrum of core services that are the essential components of the highly-advanced scientific research collaborative environment for all of DOE.
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