Hopper, Grace (1906–1992)

US computer pioneer and mathematician who created the first compiler and helped invent the computer language COBOL. She also coined the term ‘debug’.

Hopper was educated at Vassar and Yale. She volunteered for duty in World War II with the Naval Ordinance Computation Project. This was the beginning of a long association with the Navy (she was appointed rear admiral in 1983). After the war, Hopper joined a firm that eventually would become the Univac division of Sperry-Rand, to manufacture a commercial computer.

In 1945 she was ordered to Harvard University to assist Howard Aiken in building a computer. One day a breakdown of the machine was found to be due to a moth that had flown into the computer. Aiken came into the laboratory as Hopper was dealing with the insect. ‘Why aren't you making numbers, Hopper?’ he asked. Hopper replied: ‘I am debugging the machine!’

Hopper's main contribution was to develop the first English-like data processing compiler, B-0 (Flow-Matic). In 1959, she was invited to join a Pentagon team attempting to create and standardize a single computer language for commercial use. This led to the development of COBOL (Common Business-Oriented Language), still one of the most widely used languages.