what’s that in girl-years?

Long before the dawn of calculators and inexpensive desktop computers, the grinding work of large problems had to be broken up into discrete, simple parts and done by hand. Where scads of numbers needed computing—for astronomical purposes at the Royal Observatory in Greenwich, England, or to establish the metric system at the Bureau du Cadastre in Paris—such work was accomplished factory-style.

In his book When Computers Were Human, a history of the pre-machine era in computing, David Alan Grier quotes Charles Dickens’s Hard Times to capture the atmosphere of such workplaces: “a stern room with a deadly statistical clock in it, which measured every second with a beat like a rap upon a coffin-lid.” The most famous modern example of such work is probably Los Alamos, where scientists’ wives were recruited in the early stages to compute long math problems for the Manhattan Project.

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In the history of computing, the humbler levels of scientific work were open, even welcoming, to women. Indeed, by the early twentieth century computing was thought of as women’s work and computers were assumed to be female. Respected mathematicians would blithely approximate the problem-solving horsepower of computing machines in “girl-years” and describe a unit of machine labor as equal to one “kilo-girl.”

David Skinner writing about David Alan Grier's book «When Computers Were Human» in The New Atlantis