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"The Amazing" GRACE HOPPER


Grace Hopper (1906-1992) was a pioneer in computer programming who worked on the Harvard Mark I, the world’s first programmable computer. She invented the first compiler (code translator) for a computer programming language. Her work laid the groundwork for the development of COBOL, one of the first high-level programming languages. Hopper even popularized the term “bug” for a computer glitch after she physically removed a moth from the Harvard Mark II (see side panel to the right).


Wikicommons, 1984

Hopper, born Grace Brewster Murray, was from a prosperous Manhattan family. Her father was an insurance executive, and her mother was a mathematician. She went to Vassar for a degree in math and physics and completed her Ph.D. in mathematics at Yale. Hopper’s career began in academia. She married Vincent Hopper, a comparative literature professor, and became a math professor at Vassar. After a few years, however, Hopper took a partial leave to concentrate on her own mathematics studies.


It was a time of change for the country as well. The U.S. entered World War II in December 1941, after the bombing of Pearl Harbor. Then 36 years old, Hopper joined the U.S. Navy, leaving Vassar for good and divorcing her husband. As Hopper said in a speech recorded in the documentary “The Queen of Code,” “‘41 was Pearl Harbor. The world was in a very, very critical state. Everybody in the country tried to do something for that war effort.” In 1944, she graduated first in her class from the Naval Reserve Midshipmen’s School at Smith College.


Although Hopper, now a lieutenant, had long wanted to be in the Navy, she was underweight and too old to serve. She was instead assigned to the Bureau of Ships Computation Project at Harvard University where she worked alongside Howard Aiken, who designed the Harvard Mark I computer. The Mark I was fully functional during the war and played a crucial role in the Manhattan Project. By 1945, the Mark I was the world’s most easily programmable computer.


Meanwhile, another computer was being built in secret at the University of Pennsylvania. Unlike Mark I, which used punched paper inputs, the Electronic Numerical Integrator And Computer (ENIAC) was electronic and could execute five thousand commands per second to Mark I’s three commands per second. However, the Mark I had the edge, largely thanks to Hopper: the Mark I was easily programmable, whereas reprogramming ENIAC could take a whole day. 


Hopper soon realized that electronics were the way of the future. In 1949, Hopper joined the team that was developing UNIVAC I, which was designed by the inventors of ENIAC. Unlike ENIAC and Mark I, UNIVAC (Universal Automatic Computer) was designed specifically for business and commercial use, but it was also used to help tabulate the 1950 U.S. Census. It was while working on the UNIVAC that Hopper created the first compiler, which translates code written in one programming language into another language. This was an extremely important breakthrough in coding, because it allowed people to translate human language into something that can instruct a computer.  “What I felt was that there was a large number of people in the country who did not like symbols. They were not mathematicians and they hated symbols, so let them write their programs in English. It was common sense,” said Hopper. This work fed into the development of COBOL, which became a dominant programming language for businesses for the rest of the 20th century.


Hopper returned to the Navy in the late-1960’s. She was promoted to the rank of captain and later rear admiral. In celebration of her retirement and long career, Hopper was rewarded the Defense Distinguished Service Medal in 1986. At the time of her retirement, Hopper was 79, the oldest active duty commissioned officer in the U.S. In accordance with her hard-working nature, Hopper then became a senior consultant to Digital Equipment Corporation, serving mostly as a goodwill ambassador and speaking about the computer science field. Hopper held this position until her death in 1992.


Grace Hopper’s impact has been widely felt in the development of modern programming and in the field of technology. She is often referred to as the “queen of code,” “mother of COBOL,” and “amazing Grace.”


Julia Chen

First Published 2/25/2015



Design for a

Calculating Machine

Hopper's Moth in the Computer,

the original computer "bug"


click to enlarge



Wikicommons, uploaded by Daderot



History of Computing















Babbage's Difference Engine, No. 2



Influenced by the day's mechanical automata, Englishman Charles Babbage was inspired to develop complex machines that performed mathematical computations. His mathematical machines were so complicated and massive that they were never built. His Difference Engine No. 2 was completed in 2000, and it is currently housed in the computing section of the British Science Museum. It weighs over three tons.


Babbage held the Lucasian Chair of Mathematics at Cambridge from 1828-1839, and he helped to found organizations aimed at making science acceptable to a wide audience, inclucing the British Association for the Advancement of Science (BAAS).




Biographies of Babbage



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