John D. McCalpin is a Research Scientist at the Texas Advanced Computing Center of the University of Texas at Austin.  His work relates the low-level performance characterics of processors with the performance of real-world applications.  Before TACC, his career included twelve years in performance analysis and system architecture in the computer industry (AMD, IBM, SGI).  Prior to his industrial career, John was engaged in research and teaching on numerical simulation of the large-scale circulation of the oceans.  As an oceanographer, he developed the STREAM benchmark -- a simple code to measure sustained memory bandwidth.