1939 - John Vincent Atanasoff, a professor at Iowa State University, working with graduate student Clifford Berry, develops the first electronic digital computer. The computer has vacuum tubes and stores data in capacitors but it uses binary code like present-day computers and is able to perform additions and subtractions. Several other scientists, both in the United States and elsewhere, worked on digital computing machines and the efforts to perfect them were intensified during and after World War II. (DOE photo)