Grace Brewster Hopper (née Murray; December 9, 1906 – January 1, 1992) was an American computer scientist, mathematician, and United States Navy rear admiral. She was a pioneer of computer programming, credited with devising the theory of machine-independent programming languages and developing the FLOW-MATIC and COBOL programming languages. Hopper was also one of the first programmers on the Harvard Mark I computer and authored the first computer manual, "A Manual of Operation for the Automatic Sequence Controlled Calculator."
Born in New York City, Hopper earned a Ph.D. in mathematics from Yale University and taught at Vassar College before joining the Navy Reserve during World War II. Her career spanned academia, industry, and the military, and she became a prominent advocate for making programming more accessible through English-based languages. Her work laid foundations for modern software development, and she received numerous honors, including the National Medal of Technology and the Presidential Medal of Freedom.
Early life and education
Grace Brewster Murray was born in New York City, the eldest of three children. Her parents, Walter Fletcher Murray and Mary Campbell Van Horne, were of Scottish and Dutch descent. Her great-grandfather, Alexander Wilson Russell, was a US Navy admiral who fought in the Battle of Mobile Bay during the Civil War. As a child, Hopper was intensely curious; at age seven, she dismantled seven alarm clocks to understand their mechanics, after which her mother limited her to one clock. This curiosity persisted throughout her life, exemplified by her habit of keeping a clock that ran counterclockwise to challenge conventional thinking.
For preparatory school, Hopper attended the Hartridge School in Plainfield, New Jersey. She was initially rejected for early admission to Vassar College at age 16 due to low Latin test scores but was admitted the following year. She graduated Phi Beta Kappa from Vassar in 1928 with a bachelor's degree in mathematics and physics. In 1930, she earned a master's degree from Yale University, and in 1934, she completed a Ph.D. in mathematics at Yale under the direction of Øystein Ore, with a dissertation titled "New Types of Irreducibility Criteria." Hopper began teaching mathematics at Vassar in 1931 and was promoted to associate professor in 1941.
In 1930, she married Vincent Foster Hopper, a New York University professor; they divorced in 1945, and she retained his surname.
World War II and the Harvard Mark I
During the early years of World War II, Hopper attempted to enlist in the Navy but was rejected for being too old at 34 and underweight, and because her mathematics professorship was deemed valuable to the war effort. In 1943, she obtained a leave of absence from Vassar and joined the United States Navy Reserve as part of the WAVES program. She required an exemption to be commissioned, as she was 15 pounds below the Navy's minimum weight of 120 pounds. After training at the Naval Reserve Midshipmen's School at Smith College, she graduated first in her class in 1944 and was assigned to the Bureau of Ships Computation Project at Harvard University as a lieutenant, junior grade.
At Harvard, Hopper worked on the Mark I computer, also known as the Automatic Sequence Controlled Calculator, under the leadership of Howard H. Aiken. She co-authored three papers with Aiken on the Mark I. Her request to transfer to the regular Navy at the end of the war was denied because she was two years older than the cutoff age of 38, so she continued in the Navy Reserve. Hopper remained at the Harvard Computation Lab until 1949, declining a full professorship at Vassar to work as a research fellow under a Navy contract.
UNIVAC and the development of compilers
In 1949, Hopper joined the Eckert–Mauchly Computer Corporation as a senior mathematician, contributing to the development of the UNIVAC I, the first large-scale electronic computer marketed in 1951. She later served as director of Automatic Programming Development for Remington Rand, which acquired the company. Hopper advocated for a programming language using English words, but her idea was initially rejected; she was told that computers could not understand English. She persisted, arguing that it was easier for most people to write English statements than symbols, and that computers could translate them into machine code.
In 1952, Hopper published her first paper on compilers and completed her initial compiler, known as the A-0 System, which functioned as a linker and loader. In 1954, Eckert–Mauchly appointed her to lead the department for automatic programming, and she oversaw the release of early compiled languages, including FLOW-MATIC. These efforts demonstrated the feasibility of machine-independent programming, laying groundwork for later high-level languages.
COBOL and machine-independent languages
Hopper's work culminated in the creation of COBOL (Common Business-Oriented Language), an early high-level programming language still in use today. In 1959, she participated in the CODASYL consortium, which aimed to develop a machine-independent language based on English words. COBOL was designed to be readable and portable across different computer systems, a radical departure from assembly-level programming. Hopper promoted COBOL throughout the 1960s, and it became widely adopted in business and government applications. Her theory of machine-independent programming languages influenced subsequent developments in software engineering, including later languages and compilers.
Later career and military service
Hopper continued to serve in the Navy Reserve, eventually achieving the rank of rear admiral. Her military career spanned several decades, and she retired from active duty in 1986, at which point she was the oldest serving officer in the US Navy. She remained active in computing, giving lectures and advocating for innovation. Hopper was known for her aphorism, "It's often easier to ask for forgiveness than to ask for permission," and for her efforts to challenge bureaucratic inertia.
Legacy and honors
Hopper received 40 honorary degrees from universities worldwide during her lifetime. A college at Yale University was renamed in her honor. The US Navy named the Arleigh Burke-class guided-missile destroyer USS Hopper after her, and the Cray XE6 "Hopper" supercomputer at NERSC, the "Grace" supercomputing cluster at Texas A&M University, and the Nvidia GPU architecture "Hopper" also bear her name. In 1991, she was awarded the National Medal of Technology. On November 22, 2016, President Barack Obama posthumously awarded her the Presidential Medal of Freedom. In 2024, the Institute of Electrical and Electronics Engineers (IEEE) dedicated a plaque at the University of Pennsylvania honoring her invention of the A-0 compiler, which functioned as a linker and loader, during her time as a lecturer in the School of Engineering.
Hopper's contributions to computing are recognized as foundational, particularly her emphasis on making programming languages more human-readable and her role in developing early compilers. Her work influenced later developments in Artificial intelligence and Machine learning, where high-level abstractions and Large language models rely on similar principles of translating human intent into machine-executable code. Her legacy persists in modern programming practices and in the ongoing evolution of Generative AI systems.
Personal life and death
Hopper never remarried after her divorce from Vincent Foster Hopper. She died on January 1, 1992, in Arlington, Virginia. She was buried with full military honors at Arlington National Cemetery. Her life and work have been the subject of numerous biographies and documentaries, and she remains an iconic figure in the history of computing.