Bill has served as a member of the board of directors since July 2012. He has been a member of Sequoia Capital, a venture capital firm, since October 2011. He currently serves on the board of directors of multiple private companies, and he served on the board of directors of Clearwell Systems, Inc. from March 2005 to June 2011, when it was acquired by Symantec, Inc. Prior to joining Sequoia Capital, Bill held a number of roles at Google Inc. from April 2003 to September 2011, including senior vice president of engineering. At Google, he was responsible for security efforts as well as serving on the executive committee and as an advisor to the founders and Eric Schmidt. Prior to Google, Bill co-founded Entrisphere, Inc., a telecom equipment vendor, and served as its initial chief executive officer and in other roles from November 1999 to December 2002. From 1980 to 1999, Bill held a number of roles at Bell Labs, Inc. (originally part of AT&T, Inc. and then Lucent Technologies, Inc.), including vice president of the Computing Sciences Research Center. Bill has held adjunct and visiting faculty roles at Stanford University, Duke University, and ETH Zürich. He has a B.S. and M.S. in mathematics from California Institute of Technology and an M.S. and Ph.D. in computer science from Stanford University.