In 1947, Grace Murray Hopper was working on the Harvard University Mark II Aiken Relay Calculator (a primitive computer).
The 74-year-old captain, who is still on active duty, was a pioneer in computer technology during World War II. At the C.W. Post Center of Long Island University, Hopper told a group of Long Island public school administrators that the first computer "bug" was a real bug -- a moth. At Harvard one August night in 1945 1947, Hopper and her associates were working on the "granddaddy" of modern computers, the Mark I Mark II. "Things were going badly; there was something wrong in one of the circuits of the long glass-enclosed computer," she said. "Finally, someone located the trouble spot and, using ordinary tweezers, removed the problem, a two-inch moth. From then on, when anything went wrong with a computer, we said it had bugs in it."
Hopper said that when the veracity of her story was questioned recently, "I referred them to my 1945 1947 log book, now in the collection of Naval Surface Weapons Center, and they found the remains of that moth taped to the page in question."