the first computer bug
loreprogrammingops culture
The moth taped into the Harvard Mark II logbook on September 9, 1947, labeled 'First actual case of bug being found'.
Grace Hopper's team traced a relay fault to an actual moth, taped it into the log, and wrote the famous caption; the page survives at the Smithsonian. The joke only works because 'bug' for a technical defect was already old, Edison used it in the 1870s, which the caption itself winks at with 'actual'. So the story is true, the moth is real, and the etymology is older than the moth: the rare legend where every layer checks out.
Also known as: Grace Hopper's moth