On September 9, 1947, computer scientist Grace Hopper reported the world’s first computer bug. A bug is a flaw or glitch in a system. Thomas Edison reported “bugs” in his designs as early as the 1800s, but Hopper was the first to identify one in a computer.
In Hopper’s case, it was literally a bug. Her coworkers at Harvard University in Cambridge, Massachusetts, found that their computer was delivering consistent errors. When they opened the computer’s hardware, they found . . . a moth! The trapped insect had disrupted the electronics of the computer.
Grace Hopper, recorded the story in her log book: “It was over in another building, and the windows had no screens on them and we were working on it at night, of course, and all the bugs in the world came in. And one night she (Mark II) conked out and we went to look for the bug and found an actual large moth, about four inches in wing span, in one of the relays beaten to death, and we took it out and put it in the log book and pasted Scotch tape over it.”
According to Hopper, from then on, when anything went wrong with a computer, they said it had bugs in it.
The term “bug” had been used by engineers to describe flaws in machines as far back as Thomas Edison, but Hopper popularized “bug” and “debug” as early computer-programmer language. She was an originator of electronic computer automatic programming and a computer pioneer while working for the Navy, where she was a Rear Admiral. As a lecturer, she often told the story of the computer bug.