ENIAC was conceived in the thick of World War II, as a tool to help artillerymen calculate the trajectories of shells. Though construction began a year before D-Day, the computer wasn’t activated until November 1945, by which time the U.S. Army’s guns had fallen silent. But the military still found plenty of use for ENIAC as the Cold War began—the machine’s 17,468 vacuum tubes were put to work by the developers of the first hydrogen bomb, who needed a way to test the feasibility of their early designs. The scientists at Los Alamos later declared that they could never have achieved success without ENIAC’s awesome computing might: the machine could execute 5,000 instructions per second, a capability that made it a thousand times faster than the electromechanical calculators of the day. (An iPhone 6, by contrast, can zip through 25 billion instructions per second.)
We’ve come a long way.