Bug

A bug is an unintended and unwanted property or behavior of a software program or piece of hardware, especially one that causes it to malfunction. An antonym of feature: e.g. "There's a bug in the text editor: it writes things out backward." The identification and removal of bugs in a program is referred to as "". A running joke among software engineers is that if a bug is predictably reproducible and can be documented, then "It's not a bug, it's a feature."

History
The use of "bug" to mean an industrial defect had already been established in 's time, and a more specific and rather modern use can be found in an electrical handbook from 1896 (Hawkin's New Catechism of Electricity, Theo. Audel & Co.) which says: "The term "bug" is used to a limited extent to designate any fault or trouble in the connections or working of electric apparatus." It further notes that the term is "said to have originated in y and have been transferred to all electric apparatus."

This early observation may explain a common folk etymology of the term; that it came from telephone company usage, in which "bugs in a telephone cable" were blamed for noisy lines. Though this derivation seems to be mistaken, it may well be a distorted memory of a joke first current among operators more than a century ago.

In computing
Admiral (an early computing pioneer better known for inventing ) liked to tell a story in which a technician solved a  in an early  computer by pulling an actual insect out from between the contacts of one of its relays, and she subsequently promulgated bug in its hackish sense as a joke about the incident (though, as she was careful to admit, she was not there when it happened). For many years the logbook associated with the incident and the actual bug in question (a ) sat in a display case at the (NSWC). The entire story, with a picture of the logbook and the moth taped into it, is recorded in the Annals of the History of Computing, Vol. 3, No. 3 (July 1981), pp. 285--286.

The text of the log entry from September 9, 1947 reads: "1545 Relay #70 Panel F (moth) in relay. First actual case of bug being found". This wording establishes that the term was already in use at the time in its current specific sense - and Hopper herself reports that the term "bug" was regularly applied to problems in radar electronics during.

Articles

 * Software bugs have become Apple’s greatest vulnerability by Dan Moren at Macworld (2019-11-23)
 * Apple’s Most Notorious Code Bug by Komal Venkatesh Ganesan at Medium (2020-07-31)
 * Apple's 10 biggest screw-ups, ranked by Monica Chin at Mashable (2017-11-10)