Charles Babbage Herman Hollerith John Mauchley

1823 - Charles Babbage begins work on the first of his machines to mechanize solutions to general mathematical problems   1885 - Allan Marquand designs the first electric logic machine   1890 - Herman Hollerith designs the first tabulating machine   1924 - Computing-Tabulating-Recording becomes International Business Machines   1930 - Claude Shannon's Ph.D. thesis explains how electrical switching circuits can model Boolean logic   1936 - Benjamin Burack builds the first electric logic machine John Atanasoff and Clifford Berry design the first computer with vacuum tubes as switching units   1940 - John Mauchley and J. Presper Eckert build ENIAC, the first all-electronic digital computer   1945 - Vannevar Bush writes essay envisioning information-processing technology as an extension of human intellect   1947 - The transistor is perfected