The First Bug

In 1947, engineers at Harvard found a moth trapped inside the Mark II computer — causing a relay failure. Grace Hopper taped it into the logbook with the note: “First actual case of bug being found.”

The word “bug” had been used informally for technical problems before, but this was the moment it was documented and immortalized.

“From that day on, when anything went wrong with a computer, we said it had bugs in it.”