What do you think of this fact?
When your app crashes, people say: “There’s a bug in it.” Sounds like tech jargon, but once, the bug was totally literal. In 1947, a real moth got stuck inside a computer at Harvard University.
An insect in the relay
The computer was called the Mark II, a massive machine full of electromechanical relays, which are little switches that click open and shut. When it acted up, the operators went looking for the cause and found a moth trapped in one of the relays.
They pulled it out and taped it into the machine’s logbook. Next to it, they wrote: “First actual case of bug being found.”
That page still exists. The logbook is part of the collection of the Smithsonian’s National Museum of American History in Washington.
The joke only works because the word already existed
Here’s the twist in the legend: the moth wasn’t where the term came from. The note is a pun. “First actual case” only makes sense if “bug” was already common slang for technical glitches.
And it was. Thomas Edison was writing about “bugs” in his letters back in 1878, meaning the little faults and quirks in his inventions. So the Mark II operators knew the term and suddenly had a bug they could actually touch.
Grace Hopper made it famous
The person who made the story famous was Grace Hopper. The mathematician and computing pioneer worked on the Mark II team in 1947 and loved telling the anecdote later on. The logbook wasn’t hers, though, and it was her associates who found the moth.
Either way, Hopper and her colleagues helped make “bug” and “debugging” standard words in computer science.
Grace Hopper built a career in the US Navy and eventually reached the rank of rear admiral.
Nobody squashes moths in relays anymore. The job is still called debugging, though.