The first computer bug in history was a real bug. It wasn’t a software problem – it was a moth. It was found on 9 September 1947 inside a Harvard University computer.
It was one of the first computers that were not personal at all at the time: they were huge (this one weighed several tons); which explains why the moth had entered some hole and was got trapped in the circuitry of the machine causing them to go haywire. The scientists working on it immediately suspected that an insect had gotten into it: it was reasonable.
He left then the operation to debug the Harvard computer, or rather free it from the clandestine insect (today debugging is a verb that is used when it comes to correcting software malfunctions). The computer was the Harvard Mark II. The Mark I it had served to win the Second World War; this had been completed precisely in 1947 thanks to a loan from the United States Navy which planned to use it for ballistic calculations for missile trajectories. It still had to be delivered to the clients and these operating problems had to be solved.
When the computer was opened scientists found the moth trapped in the circuit; it is not known if she was still alive or already dead but soon after she was lying under a strip of transparent tape in an official report that called her “the first insect found in a computer”. The report was written by Grace Hopper, which is why Hopper is sometimes given credit for the discovery, but that’s not the case. She was a team scientist with a PhD in mathematics, who went down in history as one of the first computer programmers (she was responsible for the foundations of a once very popular language, Cobol, which will be released ten years after the first debugging. ).
We don’t know when the expression bug and the verb to debug in computer science have taken on another meaning, the contemporary one. Probably very soon. But someone remembers that the same expression, bug, was used by a great inventor of many years before, Thomas Edison to describe malfunctions of his machines experimental (there were still no computers in his day). In a letter from 1878 he begins: “Dear sir, you were partially right, I found a bug in my system”.