This report presents the United States research and development program for 1993 for high performance computing and computer communications (HPCC) networks. The first of four chapters presents the program goals and an overview of the federal government's emphasis on high performance computing as an important factor in the nation's scientific and technological advancement, economic strength, and national security. Needs and benefits, program description, goals, strategy, and the program management approach are discussed in this chapter. Chapter two describes HPCC program components, including High Performance Computing Systems (HPCS), Advanced Software Technology and Algorithms (ASTA), the National Research and Education Network (NREN), and Basic Research and Human Resources (BRHR). Program development and agency budgets are addressed in chapter three, which includes discussions of program planning, evaluation criteria, agency budgets, and descriptions of programs of the Defense Advanced Research Projects Agency, the National Science Foundation, the Department of Energy, the National Aeronautics and Space Administration, the National Institutes of Health, the National Oceanic and Atmospheric Administration, the Environmental Protection Agency, and the National Institute of Standards and Technology. Chapter four, "Grand Challenge and Supporting Technology Case Studies," provides examples of high performance computing and computer communications technologies designed to represent the diversity and significance of application areas. Included are Magnetic Recording Technology, Rational Drug Design, High Speed Civil Transports, Catalysis, Fuel Combustion, Ocean Modeling, Ozone Depletion, Digital Anatomy, Air Pollution, Design of Protein Structures, Venus Imaging, and Technology Links Research to Education. A glossary of terms concludes the report. (DB)