The first computer bug was a real moth

The famous first computer bug was a real moth. On September 9, 1947, a moth lodged between relay contacts in Harvard's Mark II, an electromechanical computer. 1

The operators taped the moth into the logbook and wrote, "First actual case of a bug being found." The entry names Relay #70, Panel F, at 15:45. 1

The word bug already belonged to engineering. Thomas Edison used bug for technical trouble in the nineteenth century, and an 1889 newspaper used the word for a phonograph defect. 2

Grace Hopper was present and later helped popularize the incident. The preserved logbook was probably not hers. 12

Remember the chain: a machine fault, a moth, a taped logbook, and a word engineers already knew.