First Computer Bug Was Real

Long before the age of microchips, computers were colossal machines filling entire rooms with thousands of clicking electromechanical relays. The Harvard Mark II, a behemoth of its time, was no exception. When it began malfunctioning on a warm day in September 1947, a team of technicians, including the pioneering computer scientist Grace Hopper, set out to diagnose the problem. This wasn't a matter of running a diagnostic program; it required a physical inspection of the computer's vast and complex circuitry to find the source of the error.

Tucked inside Relay #70, the team discovered the culprit: a small moth that had been electrocuted, its body jamming the mechanical switch. An operator carefully removed the insect with tweezers and taped it into the official logbook. Beside it, a note was made: "First actual case of bug being found." While the term "bug" had been used by engineers for decades to describe inexplicable technical glitches—Thomas Edison even used it in the 1870s—this literal, physical example gave the word a new and lasting life. The tangible evidence of the moth, preserved for posterity, cemented "computer bug" into the lexicon of the digital age as the perfect metaphor for a small, hidden flaw causing major problems.