Debugging – Bug History

Why is it called a bug? 

The first computer “bug” was a real bug — a moth.  In 1947, Rear Admiral Grace Murray Hopper was working on the Harvard University Mark II Aiken Relay Calculator, an electromechanical computer.

Grace Hopper tells the story:

“Things were going badly; there was something wrong in one of the circuits of the long glass-enclosed computer.  Finally, someone located the trouble spot and found a Moth trapped between points at Relay # 70 on Panel F.

Using ordinary tweezers, we removed the two-inch moth. From then on, when anything went wrong with a computer, we said it had bugs in it.”

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The operators affixed the moth to the computer log, with the entry: “First actual case of bug being found”. The team put out the word that they had “debugged” the machine.

Who was Rear Admiral Grace Murray Hopper?

image003 Grace Hopper (1906-1992) made numerous pioneering contributions to computer science. She was one of the field’s first programmers, she led the development of the programming language COBOL, she did early compiler work, and she created the term debugging and computer bug.

  • The USS Hopper (DDG-70) is named in honor of Rear Admiral Grace Murray Hopper.
  • Grace Hopper is famous for her nanoseconds visual aid. In 1986, she explained the concept of a nanosecond to David Letterman:
  • Grace Hopper’s legacy was an inspiring factor in the creation of the Grace Hopper Celebration of Women in Computing. Held yearly, this conference is designed to bring the research and career interests of women in computing to the forefront.

Was it the first use of the term “bug?”

The term “bug” was used to describe problems in radar electronics during WWII (Grace Hopper was familiar with the use of term in this context).  The terms bug was used earlier to describe industrial defects.