In 1947, operators of the Harvard Mark II computer found a real moth jammed inside a relay — and taped it into the logbook as 'the first actual case of bug being found.' That logbook is still preserved today at the Smithsonian. The word 'bug' meaning a computing error has stuck ever since. Follow for a new fact every day.

• americanhistory.si.edu
• computerhistory.org
• ivizlab.sfu.ca
• ieeexplore.ieee.org
• daily.jstor.org

The very first computer bug was a real insect. On September 9, 1947, operators of the Harvard Mark II computer in Massachusetts discovered a moth had fluttered inside one of the machine's electromechanical relays and jammed it. The relay was a mechanical switch roughly the size of a matchbox, and the moth's wings were just wide enough to stop it from closing. The team pulled it out with tweezers, taped it into the official logbook, and wrote next to it: 'First actual case of bug being found.' The logbook still exists today, preserved at the Smithsonian Institution's National Museum of American History in Washington, D.C. Grace Hopper, the pioneering Navy mathematician who worked on that machine, later popularized the story — and the word 'bug' to mean a computing error has been with us ever since. Follow for a fact every day.