This Day in History: September 9
September 9, 1947
First Instance of Actual Computer Bug Being Found
At 3:45 p.m., Grace Murray Hopper records 'the first computer bug' in the Harvard Mark II computer's log book. The problem was traced to a moth stuck between relay contacts in the computer, which Hopper duly taped into the Mark II's log book with the explanation: “First actual case of bug being found.” The bug was actually found by others but Hopper made the logbook entry.