David A. Patterson was the first in his family to graduate from college (1969 A.B UCLA), and he enjoyed it so much that he didn't stop until a PhD, (1976 UCLA). After 4 years developing a wafer-scale computer at Hughes Aircraft, he joined U.C. Berkeley in 1977. He spent 1979 at DEC working on the VAX minicomputer. He and colleagues later developed the Reduced Instruction Set Computer (RISC). By joining forces with IBM's 801 and Stanford's MIPS projects, RISC became widespread. In 1984 Sun Microsystems recruited him to start the SPARC architecture. In 1987, Patterson and colleagues wondered if tried building dependable storage systems from the new PC disks. This led to the popular Redundant Array of Inexpensive Disks (RAID). He spent 1989 working on the CM-5 supercomputer. Patterson and colleagues later tried building a supercomputer using standard desktop computers and switches. The resulting Network of Workstations (NOW) project led to cluster technology used by many startups. He is now working on the Recovery Oriented Computing (ROC) project. In the past, he served as Chair of Berkeley's CS Division, Chair and CRA. He is currently serving on the IT advisory committee to the U.S. President and has just been elected President of the ACM. All this resulted in 150 papers, 5 books, and the following honors, some shared with friends: election to the National Academy of Engineering; from the University of California: Outstanding Alumnus Award (UCLA Computer Science Department), McEntyre Award for Excellence in Teaching (Berkeley Computer Science), Distinguished Teaching Award (Berkeley); from ACM: fellow, SIGMOD Test of Time Award, Karlstrom Outstanding Educator Award; from IEEE: fellow, Johnson Information Storage Award, Undergraduate Teaching Award, Mulligan Education Medal, and von Neumann Medal. John L. Hennessy is the president of Stanford University, where he has been a member of the faculty since 1977 in the departments of electrical engineering and computer science. Hennessy is a fellow of the IEEE and the ACM, a member of the National Academy of Engineering, the National Academy of Science, the American Academy of Arts and Sciences, and the Spanish Royal Academy of Engineering. He received the 2001 Eckert-Mauchly Award for his contributions to RISC technology, the 2001 Seymour Cray Computer Engineering Award, and shared the John von Neumann award in 2000 with David Patterson. After completing the project in 1984, he took a one-year leave from the university to co-found MIPS Computer Systems, which developed one of the first commercial RISC microprocessors. After being acquired by Silicon Graphics in 1991, MIPS Technologies became an independent company in 1998, focusing on microprocessors for the embedded marketplace. As of 2004, over 300 million MIPS microprocessors have been shipped in devices ranging from video games and palmtop computers to laser printers and network switches. Hennessy's more recent research at Stanford focuses on the area of designing and exploiting multiprocessors. He helped lead the design of the DASH multiprocessor architecture, the first distributed shared-memory multiprocessors supporting cache coherency, and the basis for several commercial multiprocessor designs, including the Silicon Graphics Origin multiprocessors. Since becoming president of Stanford, revising and updating this text and the more advanced Computer Architecture: A Quantitative Approach has become a primary form of recreation and relaxation.