Ada Lovelace wrote the first computer algorithm. Grace Hopper invented the first compiler. Programming was mostly women's work until World War II. Harvard Computers were women paid less than factory workers cataloging stars. Women classified stars at three per minute. Black women computers segregated at NACA worked harder without promotions. ENIAC programmers were six women who understood hardware but got no credit. By 1943 nearly all computers were women due to patience traits. Women invented COBOL precursors and optimized programs. Women proportion peaked at 37% CS graduates in 1984 then declined. No firm explanations for late 20th century gender disparity. Women did ballistics and cryptography but roles minimized. Post-WWII aptitude tests shifted hiring to men from 50%+ women field. Black women at Langley re-did passed college courses unlike whites. Women volunteered for free computing work. Programming professionalized into men's domain after 1960s.