I just came across this. I didn’t know it before, but now I know the story of how a computer error became to be known as a “bug”, and removing the bug became known as debugging the code.
In 1947, Grace Murray Hopper was working on the Harvard University Mark II Aiken Relay Calculator (a primitive computer).
On the 9th of September, 1947, when the machine was experiencing problems, an investigation showed that there was a moth trapped between the points of Relay #70, in Panel F.
The operators removed the moth and affixed it to the log. (See the picture above.) The entry reads: “First actual case of bug being found.”
(See the link at the bottom of this page for a much larger version of this picture.)
The word went out that they had “debugged” the machine and the term “debugging a computer program” was born.