Photograph cc-by Marcin Wichary

Charles P. (Chuck) Thacker was one of the great generation that took networking and the personal computer into the mainstream world. After studying at UC Berkeley and developing the Berkeley Timesharing System on an SDS 940 mainframe, he was one of the ‘dealers of lightning’ recruited by Bob Taylor when he set up the Computer Systems Lab at Xerox PARC. In three years, Chuck, Butler Lampson, Bob Metcalfe, David Boggs, Alan Kay and Charles Simonyi invented much of the computing kit we use today — from graphical windowing interfaces and the mouse (adapted from Douglas Engelbart’s original design) to Ethernet local-area-networking and the laser printer. I got to know him in the late 1990s when I was writing my history of the Net and he was working in Cambridge in the Microsoft Research Lab. The photograph captures him as I remember him: large, imperturbable, wise, friendly.