Why are computer software errors called 'bugs'?

So where did the term "bug" come from?

"Bug" comes from a term used by Grace Hopper - a mathematician and US Navy officer - in the bug log of the Mark II, a giant computer that took up an entire room at Harvard University ( America).

Grace Hopper is best known for her work developing the Mark II system and played a key role in developing the first programming languages ​​and compilers, such as COBOL which is still used in many business and military environment.

In 1947, the Mark II began producing false readings overnight and without warning. Grace Hopper and the scientists in charge of the system quickly began investigating the cause of this error. The problem was discovered to be related to a moth that had crawled inside the computer and caused a short circuit in one of the relays. This physical problem caused the computer to give incorrect results.

At the time, there was a logbook documenting errors with systems like the Mark II. It was Hopper who took out the moth that caused the problem and pasted it into this notebook. Hopper wrote the term "bug" next to the moth as a reference to a butterfly crawling into the computer and causing problems.

Nowadays any computer error, whether it is a system or code glitch, uses the term "bug" to emphasize the importance of thoroughness when investigating a problem. This term also reminds us that even a very small error can have big consequences.

Marvin Fry

Update 22 July 2024