Born on Oct.28,1955，Gates grew up in Seattle with his two sisters.Their father，William H．Gates H，was a Seattle attorney.Their late mother，Mary Gates，was a schoolteacher，University of Washington regent，and chairwoman of United Way International.Gates attended public elementary school and the private Lakeside School.There，he discovered his interest in software and began programming computers at age 13. In 1973，Gates entered Harvard University as a freshman，where he lived down the hall from Steve Ballmer，now Microsoft's chief executive officer.While at Harvard，Gates developed a version (版本) of the programming language BASIC for the first microcomputer－the MITS Altair.