Prior to joining the University of Washington in 1969, he was a Research Engineer with the Laboratoire de Calcul, Université de Grenoble, and a member of the Digital Technology Group at UCLA (1966-69). His present interests are in parallel and distributed processing and computer systems architecture. He is author or coauthor of more than 100 papers in these areas and the author of the two textbooks ``Computer Systems Architecture'' (Computer Science Press, 1980) and "Microprocessor Architecture: From Simple Pipelines to Chip Multiprocessors" (Cambridge University Press, 2010).