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2.  High Performance Computing Systems

 When the HPCC Program began in 1991, traditional vector computers  were still the primary highperformance computing systems.  Those  systems were known to be approaching their physical limits, anda  number of computing systems vendors were developing parallel  systems that promised to overcomethose limits.  Today all major  U.S. vendors have adopted parallel technology.  Products span a wide range, including scalable parallel, fine- and coarse-grained parallel,  vector and vector/parallel,networked workstations with high speed  connectivity, and heterogeneous systems connected by highspeed  networks. 
**Performance Accomplishments**
One of the fastest of these systems, an Intel Paragon with 1,904  nodes (each consisting of two Inteli860 processors) and 38 GB  memory at DOE's Sandia National Laboratories, achieved a world  record143.4 gigaflops (Gflops) on the Massively Parallel (MP)  Linpack benchmark. 
By loosely coupling two large Paragons with a total of 2,256 of  Intel's new multiprocessing nodes(each consisting of three i860 XP  microprocessors, for a total of 6,768 processors), world records of 281 Gflops on the MP Linpack benchmark and 328 Gflops on a double- precision complex LU factorizationcode were realized.  The systems  were connected by 16 HiPPI channels with over 3 GB/s capacity.  Both ran SUNMOS (Sandia/UNM Operating System), whose  development was funded by DOE.  SUNMOS is alightweight custom  message-passing OS kernel optimized for high performance and low  latency. Applications demanding this level of performance are  described beginning inSection II.6. 
http://www.cs.sandia.gov/HPCCIT/main.html 
Applications exhibiting half teraflops performance over a network  are expected to be demonstrated onthe exhibition hall floor at  Supercomputing '95 in November 1995 in San Diego.  The HPCC  Programremains well on track toward demonstrating technologies  capable of sustaining one trillion operationsper second (teraops)  performance on select large scientific and engineering problems. 
ARPA is the lead HPCC agency developing the scalable computing  technologies capable of sustainedteraflops and faster performance.   The ARPA program will enable industry to develop such systems for broad commercial use while enabling defense agencies to procure  large-scale versions from thelow-cost commercial technology base  for special applications without redeveloping architectures, operating systems, or applications software.  In FY 1995 ARPA will  support the hardware, software,and system architecture design of  teraflops-scale systems expected to emerge in FY 1996.  Efforts include support for the convergence of architectural models (for  example, message passing anddistributed shared memory, or  scalable vector and massively parallel).  That will result in systems that run critical defense parallel applications more efficiently (for  example, automatic targetrecognition, sensor fusion), and critical  mobile targets.  These systems will take advantage ofARPA's  efforts in microsystems that are expected to produce computer  backplane data ratesapproaching one Gb/s per wire.  FY 1995 ARPA  efforts will also create early prototypes ofsignificantly higher  performance and secure operating systems.  In workstation cluster  computing,ARPA will explore this more loosely coupled scalable  computing architecture, including work onresource discovery,  operating environments, and new models of computing.