From
http://www.neystadt.org/john/humor/Bugs-Origin.htm
Ever wondered about the origins of the term "bugs" as applied to computer technology? U.S. Navy Admiral Grace Murray Hopper has firsthand explanation. She was on duty until 1992, when she died being. Being 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, Hopper and her associates were working on the "granddaddy" of modern computers, the Mark I. "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 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."