http://awards.acm.org/citation.cfm?id=1336106&srt=all&aw=140&ao=AMTURING&yr=2009
For the pioneering design and realization of the first modern personal
computer -- the Alto at Xerox PARC -- and seminal inventions and
contributions to local area networks (including the Ethernet),
multiprocessor workstations, snooping cache coherence protocols, and tablet
personal computers.