bug：機械の中のガ

Every programmer knows the word "bug". It means a mistake in a computer program that makes it behave in the wrong way. But why do we use the name of an insect for a software problem? There's a famous story about this. On 9 September 1947, a team of engineers at Harvard University was working on a huge early computer called the Mark II. The machine kept making errors, and when they looked inside, they found the cause: a moth had got trapped in one of the machine's electrical switches. The engineers carefully removed the moth and taped it into their logbook. Next to it, someone wrote: "First actual case of bug being found." The story was later told many times by Grace Hopper, a pioneering computer scientist who worked on the machine, and the logbook – with the moth still in it – is now kept in a museum in Washington. But here's the interesting part. Look closely at the words "first actual case". The engineers were making a joke. They already used "bug" to mean a technical fault, and they thought it was funny that this time, the bug was a real insect. In fact, engineers had been talking about "bugs" for many decades. The famous inventor Thomas Edison used the word in a letter in 1878 to describe small faults and difficulties in his inventions. So the moth didn't create the word "bug". But it did give us one of the best stories in the history of computing – and the phrase "debugging" has been part of every programmer's life ever since.