Howard Aiken's third machine: the Howard Mark III calculator or Aiken-Dahlgren electronic calculator

The lines of computing machines that had their origin in the days immediately preceding World War II include a series of calculators which Howard Aiken, a professor of applied mathematics at Harvard University, designed. Starting with the Mark I in 1944, Aiken spearheaded an effort that provided not only the physical means of computation but also the tools to direct them and the people to operate them. The third in this sequence of machines was an innovation in design and implementation, while at the same time being conservative in the selection of components. The Harvard Mark III Calculator had the potential to be a significant entry into the field of computing, but events slowed its completion until competitors finished other markedly superior systems. The Mark III was not a machine that would be emulated or replicated beyond its lifetime, but the people who planned it, built it, programmed it and operated it went on to make significant contributions to the science and practice of computing.