Grace Murray Hopper graduated Phi Beta Kappa with majors in math, physics, and economics from Vassar College in 1928. She went on to receive an M. A. in math (1930) and a Ph. D. (1934) from Yale University in mathematics. After working in an academic setting as instructor, assistant professor, associate professor, and researcher, she joined the WAVES (Women Accepted for Volunteer Emergency Service), a unit of the US Naval Reserve, as a Lieutenant in 1943 to help the war effort. Assigned to work on the Bureau of Ordinance Computation Project at Harvard University on the computation of ballistic trajectories, she used the Mark I, the first electronic (as opposed to mechanical) digital computing device - a forerunner of the modern computer. After the war, she joined Eckert-Mauchly (which later became later Sperry Rand), where she continued her work on electronic computing machines until her retirement in 1967. Recalled to active duty in the Navy in 1967 (at the age of 60), she worked at the Pentagon for the next twenty years developing its programming languages. Promoted to captain in 1973 while on the retired list, a precedent in the Naval Reserve requiring an act of Congress, she retired for her second and final time in 1986, at the age of 80, receiving the Distinguished Service Medal, the Defense Department's highest honor.

      At Harvard, she developed the first operating programs for the Mark I. At UNIVAC, she helped to develop the first commercially viable computer, the UNIVAC I. In 1952, she developed the first practical computer compiler, a program which translates English like commands into the strings of 0s and 1s which the computer needs to perform its operations.

      Now, to non-computer experts this might not seem like much of a big deal, but to computer types, this is a very big deal. Let me give a stripped down example of what a computer compiler does. For a computer to add 2 numbers it must follow several steps:

      Get the first number from the user, translate it into binary, and store in the accumulator
      Get the second number from the user, translate it into binary, store in the temporary memory.
      Add the numbers, save the result in the accumulator, convert the number to decimal, display the result to the user.

      Computers only manipulate strings of 0s and 1s so all commands must be given as strings of 0s and 1s.

      Each series of instructions (string of 0s and 1s) must be repeated each time the operation is performed.

      A compiler translates commands given in a high-level language into a string of 0s and 1s, the machine language code, required for the computer to perform the desired tasks. With a compiler, the above computer code in a high-level language might look like this:

      read, A, B
      C = A + B
      print, C

      In short, the development of the computer compiler, a program which writes its own machine language program from commands given in a higher level language, made the computer a viable product because it could be much more easily programmed. Her path-breaking, prototype compiler lead to the first English-language compiler, COBOL (Common Business Oriented Language). Later work included development of virtual storage, greatly increasing the effective memory available to the computer, the computer operating system, and parallel processing. She continued her pioneer work on machine computation throughout her life, publishing more than 50 papers and receiving honorary degrees from 10 American and foreign universities.

      The computer on which you are reading this biography is possible in large part due to Hopper's ground-breaking work. Obviously, any list of the most important men or women of the millennium which excludes Hopper is incomplete.

Reference

      Autumn Stanley, Mothers and Daughters of Invention, Rutgers University Press, 1995, pp. 438 - 442

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