Grace Brewster Hopper

1906-1992

American Mathematician and Computer Programmer

Grace Hopper developed COBOL, a computer programming language, in the 1950s and her related innovations, such as compilers used for business processes, provided a foundation for more sophisticated computing systems. A computer software pioneer, Hopper encouraged her colleagues to enhance technology for data processing. She set precedents in technological professions that were considered almost exclusively male at the time, enabling other women to gain access to computing careers. Hopper's achievements helped make the production of commercial computers possible.

Born on December 9, 1906, in New York City, Hopper was encouraged by her parents, Walter Fletcher and Mary Campbell (Van Horne) Murray, to pursue her academic ambitions, especially in mathematics. Hopper resisted being restrained by conventional gender roles. Curious about how mechanical devices worked, she explored her home to investigate small machines such as clocks. Attending private girls' schools in New York and New Jersey, Hopper enrolled at Vassar College, where she majored in mathematics and physics, graduating in 1928. She married Vincent Foster Hopper in 1930. While teaching at Vassar, Hopper completed a master's degree and doctorate in mathematics from Yale University in the early 1930s.

When the Japanese bombed Pearl Harbor in 1941, Hopper decided to enlist in the U.S. Navy. Military officials, however, thought that she was too old and urged her to contribute to the war effort as a mathematics instructor. Instead, Hopper secured authorization to join the Naval Reserve in 1943, beginning a 43-year career. Hopper trained at midshipman's school and was commissioned a lieutenant for service in the Bureau of Ordnance Computation Project, located at Harvard University's Cruft Laboratories. Commander Howard Aiken directed Hopper to program the school's Mark I, an early digital computer. During World War II, the Mark I computer figured out projectile trajectories.

Using punched cards to input data, Hopper focused on preparing code for the Mark I computer. When the war concluded, Hopper resigned from active military duty but retained reserve status. She began work as a research fellow in physics and engineering sciences at Harvard's Computation Laboratory. Here, Hopper programmed the Mark II and III computers. In 1949 she accepted a mathematics position at the Eckert-Mauchley Computer Corporation. This company developed the BINAC (Binary Automatic Computer), which used code, rather than punched cards, for data entry. Hopper programmed BINAC with a base eight numerical system called octal that utilized the digits 0 to 7.

When the company was bought by Remington Rand Corporation (which later merged with the Sperry Corporation), Hopper was designated a systems engineer and director of Automatic Programming Development for the UNIVAC (Universal Automatic Computer) Division. She assisted John Eckert and John Mauchly, who invented the UNIVAC computer. Hopper focused on bettering compiler design in order to translate mathematical code (on tape) to machine code for performing processes. She innovated a compiler known as the Flow-Matic that understood English instructions so that the UNIVAC computers could be used for business applications. Hopper then concentrated on standardizing a universal programming language, developing COBOL (COmmon Business-Oriented Language) by 1959. This computer language recognized words—unlike its predecessors, which read numbers only.

When a moth flew into a computer that she was monitoring, Hopper developed the term "bug" to indicate a technical malfunction, and this reference was incorporated into computer terminology. Because of her age, she retired from the Naval Reserves in 1966. Navy officials, however, asked her to return to active duty to standardize computer languages that were crucial for payroll procedures. When she retired in 1986 at the rank of Rear Admiral, Hopper was the country's oldest active-duty officer. The Department of Defense presented her with its most prestigious award and she also received the National Medal of Technology. Hopper died on January 1, 1992. Five years later, a Navy destroyer was named for her.

ELIZABETH D. SCHAFER