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The first Computer Bug...

9 September 1945 : The "Bug" is Born

The First Computer Bug...

In 1945, Grace Murray Hopper was working on the Harvard University Mark II Aiken Relay Calculator. On the 9th of September, 1945, 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."

Grace Murray Hopper, who lived from 1906-1992, found the first computer bug while working in a temporary World War I building at Harvard University on the Mark II computer where a moth had been beaten to death in the jaws of a relay. She glued it into the logbook of the computer and thereafter when the machine stops (frequently) they say that they are "debugging" the computer. The very first bug still exists in the National Museum of American History of the Smithsonian Institution. The word bug and the concept of debugging had been used previously, perhaps by Edison, but this was probably the first verification that the concept applied to computers.

Moth found trapped between points at Relay # 70, Panel F, of the Mark II Aiken Relay Calculator while it was being tested at Harvard University, 9 September 1945. First actual case of bug beeing found. Copyright: Smithsonian - National Museum of American History

Rear Admiral Grace Murray Hopper, USNR, (1906-1992)

Grace Murray (Hopper) was born in New York City on 9 December 1906. She graduated from Vassar College in 1928 and received a PhD in Mathematics from Yale University in 1934. She was a member of the Vassar faculty from 1931 to 1943, when she joined the Naval Reserve.

Commissioned a Lieutenant (Junior Grade) 1944, she was assigned to the Bureau of Ordnance and immediately became involved in the development of the then-embryonic electronic computer. Over more than four decades to follow, she was in the forefront of computer and programming language progress.

During her work with Mark II, Hopper was credited with coining the term "bug" in reference to a glitch in the machinery. This story is apparently a bit of computer folk-lore, however, as the term had already been used by Harvard personnel for several years to describe problems with their computers. It is the case that she and her team of programmers did find a moth which flew through an open window and into one of Mark II's relays, temporarily shutting down the system. The moth was removed and pasted into a logbook [Photo of that bug]. At that time the use of the word "bug" referred to problems with the hardware. In the mid 1950's, Hopper extended the meaning of the term "debug" to include removing programming errors.

The Term

So, where did the term "bug" come from?

Well, the entry ("First actual case of bug being found.") shows that the term was already in use before the moth was discovered. Grace Hopper also reported that the term "bug" was used to describe problems in radar electronics during WWII.

The term was use during Thomas Edison's life to mean an industrial defect. And in Hawkin's New Catechism of Electricity, an 1896 electrical handbook from Theo. Audel & Co.) included the entry:

The term "bug" is used to a limited extent to designate any fault or trouble in the connections or working of electric apparatus.

In discussing the origin of the term, the book notes that the term is said to have originated in quadruplex telegraphy and have been transferred to all electric apparatus. Common folk etymology says that the phrase "bugs in a telephone cable" was used to account for noisy lines. There is no support for this derivation.

Remember this quote:

"Where a calculator on the ENIAC is equipped with 18,000 vacuum tubes and weighs 30 tons, computers in the future may have only 1,000 vacuum tubes and perhaps weigh 1 1/2 tons."

Popular Mechanics, March 1949.

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