The First “Bug” Was a Real Insect

Programmers call errors “bugs,” and the most famous story behind this word is literal. On September 9, 1947, a malfunction occurred in the Harvard University Mark II computer. After a long search, engineers found a real moth stuck in one of the relays.

The team, which included Grace Hopper, one of the key figures in the history of programming, taped the moth into the logbook and wrote next to it that this was the first actual case of a bug being found. That logbook is now held at the Smithsonian National Museum of American History in Washington.

For accuracy, it should be noted that the word “bug” had been used to mean a technical problem since the time of Thomas Edison, but it was this incident that firmly established it in programmers’ vocabulary. And “debugging,” the process of fixing errors, makes up much of every programmer’s daily work today.