Marine helicopter pilot worked at Lockheed Martin, Honeywell, Intel before cofounding data storage giant EMC Corp. 1979. Took company public 1986; sold most of his shares in tech boom. Stepped down as chairman 2001. Big GOP supporter served as U.S. ambassador to Ireland during President Bush's first term. Forced to pay IRS $62 million in 2006. They claim he used an illegal tax shelter.