Matthew Battles unearths the above logbook from the Mark II, one of the “early electromechanical computers, instantiating computational logic in a vast, greasy array of switches, shafts, and clutches”:
In effect, the logbook, which resides in the Smithsonian’s Museum of American History in Washington DC, is a record of early computer bugs rendered in precise, empirical terms. And in those records, one bug stands out: on page 92, at 1545 on 9/9 1945, an actual moth was fixed to the page with a piece of tape. ‘Relay #70 Panel F/(moth) in relay,’ reads the journal; below, in what is likely Hopper’s hand, the line ‘First instance of actual bug being found.’
Alas, that use doesn’t mark the origin of the term “bug”:
Already in the late-19th century, technicians in Thomas Edison’s lab were using the word ‘bug’ to describe thorny technical problems. From the syntax of Hopper’s notes in the journal, it’s clear that engineers working on the Mark II were familiar with this usage; the ‘actual’ bug was entered into the log as a cheeky aside, a bit of lab humour. Bug is an ancient word, and its use in specific reference to creeping arthropods dates only from the 17th century, according to the Oxford English Dictionary. Prior to that, the word named the nameless: bugbears, monsters and creatures of mystery and shadow.
(Photo courtesy Smithsonian’s National Museum of American History)
The Dish 