The First Computer Bug Was a Real Bug
A moth jammed a relay on the Harvard Mark II in 1947. The operators taped it into the logbook.
On September 9, 1947, a team operating the Harvard Mark II at the Naval Surface Warfare Center found that the machine was producing wrong answers. They traced the problem to Panel F, Relay 70. Wedged between the relay contacts was a dead moth, about two inches across.
Someone — grace Hopper's log suggests it was not her personally — pulled the moth out with tweezers, taped it into the paper logbook, and wrote next to it: "First actual case of bug being found." The joke was that engineers had called glitches "bugs" for decades, but this one was literal.
The term itself is older than electronic computers. Thomas Edison wrote in an 1878 letter about "bugs" in his phonograph design: "little faults and difficulties" that crop up during development. Telegraph operators used it the same way through the late 1800s. By the 1940s, every engineer in the room would have called a hardware fault a bug without thinking.
What makes the Mark II story stick isn't the coinage. It's the tape. The logbook page, moth still attached, is now in the Smithsonian. The insect is pinned in place like a specimen — which, in a way, it is.
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