The Women of ENIAC

Each of the women shown in the photo above is holding a unit with the same storage capacity; the first two decreases in size are due to improvements in the tubes and wiring, but the last is due to the invention of the transistor. These were the calculating components of (respectively) ENIAC, EDVAC, ORDVAC, and BRELESC-I. One unit contained 108 tubes, the equivalent of 108 transistors; the CPU of the computer on which I'm writing these words has 774 million of them, which would require more than seven million of the units shown above. These early computers were hand-programmed, and these women were the first programmers of the electronic computing age; you can learn more about them here.