Admiral Grace Hopper

Grace Hopper, in full Grace Murray Hopper, née Grace Brewster Murray, (born December 9, 1906, New York, New York, U.S.—died January 1, 1992, Arlington, Virginia), American mathematician and rear admiral in the U.S. Navy who was a pioneer in developing computer technology, helping to devise UNIVAC I, the first commercial electronic computer, and naval applications for COBOL (common-business-oriented language).

After graduating from Vassar College (B.A., 1928), Hopper attended Yale University (M.A., 1930; Ph.D., 1934). She taught mathematics at Vassar before joining the Naval Reserve in 1943. She became a lieutenant and was assigned to the Bureau of Ordnance’s Computation Project at Harvard University (1944), where she worked on Mark I, the first large-scale automatic calculator and a precursor of electronic computers. She wrote the first computer manual, A Manual of Operation for the Automatic Sequence Controlled Calculator (1946), which described how to operate Mark I and was the first extensive treatment of how to program a computer. She remained at Harvard as a civilian research fellow while maintaining her naval career as a reservist.

In 1949 Hopper joined the Eckert-Mauchly Computer Corp., where she designed one of the first compilers, which translated a programmer’s instructions into computer codes, and coined the word compiler. As head programmer, she worked on the design of UNIVAC I. She remained with the firm when it was taken over by Remington Rand (1951) and by Sperry Rand Corp. (1955). In 1957 her division developed Flow-Matic, the first English-language data-processing compiler, which had many features that inspired the development of COBOL. Her development of compilers for COBOL and her strong advocacy of the language led to its widespread use in the 1960s. She retired from the navy with the rank of commander in 1966, but she was recalled to active duty the following year to help standardize the navy’s computer languages. She was promoted to commodore in 1983, and that rank was incorporated into that of rear admiral in 1985. At the age of 79, she was the oldest officer on active U.S. naval duty when she retired again in 1986.


Hopper - Digital_Computers_Advanced_Coding_Techniques_Summer_1954.pdf
Hopper - The education of the computer.pdf
Hopper - AutoCodingPaper_1955.pdf


Bugs and debugging

While she was working on a Mark II Computer at Harvard University in 1947, her associates discovered a moth that was stuck in a relay and impeding the operation of the computer. Upon extraction, the insect was affixed to a log sheet for that day with the notation, “First actual case of bug being found”. While neither she nor her crew members mentioned the exact phrase, "debugging", in their log entries, the case is held as a historical instance of "debugging" a computer and Hopper is credited with popularizing the term in computing. For many decades, the term "bug" for a malfunction had been in use in several fields before being applied to computers. The remains of the moth can be found taped into the group's log book at the Smithsonian Institution's National Museum of American History in Washington, D.C.