Why Is a Computer Problem Called a Bug?

The process of writing a computer program involves endless testing to be sure it works correctly. This task has come to be known as the "debugging" process, and the now common phrase, "getting the bugs out" is applied to just about any process where someone is working to perfect it.

The First "Debug"

The term "debug" probably came from an occurrence where an actual bug caused a computer operation to fail, causing operators to trace out the physical location of the problem.

A Buggy Relay

One of the earliest computers, the Mark II Aiken Relay Calculator, was at Harvard University. The first attempts at building computers used relays as the active devices. On September 9th, 1947, a problem with the calculator lead operators to discover a moth wedged between the contacts of Relay #70 in Panel F. The machine had been "debugged" by the operators, and that term soon spread.

The Bug Is On Display

The operators that day had actually taped the moth to their log sheet, which was acquired by the Smithsonian Institute in 1991 to be exhibited.

Earlier Uses of the Term "Bug"

While the above story is perhaps responsible for catapulting the term "debugging" into our mainstream language, the word "bug" can be traced back to the days of Thomas Edison. An 1896 electrical handbook titled, "Hawkins New Catechism of Electricity," lists "bug" as a term used to designate any trouble or fault in the connections or working of an electric apparatus.

WW II Radar Bugs

When problems occurred in radar electronics during World War II, technicians used the word "bug" to describe the faults.