UPC: A Distributed Shared Memory Programming Paradigm Tarek El-Ghazawi Department of Electrical and Computer Engineering The George Washington University Abstract UPC, or Unified Parallel C, is an explicit parallel extension of ANSI C. As in message passing, UPC allows the explicit distribution of data and work. As in the shared memory programming paradigm, however, UPC provides an easy to use syntax and semantics. UPC accomplishes this by following a distributed shared-memory programming model, and by providing constructs that facilitate explicit control of data and work distribution among threads, so that remote memory accesses can be minimized. Thus, UPC maintains the C language heritage of keeping programmers in control of and close to the hardware. In this talk the underlying concepts of UPC along with the main language features will be introduced. Initial performance results comparing UPC and MPI will be presented. It will be shown that with proper optimizations, UPC can compare favorably with other paradigms. UPC has been gaining acceptance from several vendors who are producing exploratory compilers. For more information see upc.gwu.edu. ------------------------------------------------------------ Tarek El-Ghazawi has received the Ph.D. degree in 1988 from New Mexico State University in Electrical and Computer Engineering. He is currently an Associate Professor at the Department of Electrical and Computer Engineering of the George Washington University. Dr. El-Ghazawi has also held faculty positions at the George Mason University and Florida Institute of Technology. His research interests include high-performance computing and architectures, parallel I/O, and performance evaluations. Dr. El-Ghazawi has published extensively in these areas and his research has been frequently supported by the DoD, NASA, and NSF. He has also served as a visiting scientist with CESDIS at NASA GSFC, and RIACS at NASA Ames Research Center. He is currently an associate editor for the International Journal on Parallel and Distributed Systems and Networking, and was a guest editor for the IEEE Concurrency, special track on High-Performance Data Mining. He is a Senior Member of the IEEE, a member of the ACM, and a member of Phi Kappa Phi.