I

N THE BEGINNING, computers were people.

When America entered World War II in 1941, a need arose to calculate precise trajectories of ballistic weapons. At the Ballistic Research Laboratory, Aberdeen Proving Ground, Md., a hundred or so women — all college graduates — were enlisted to compute artil- lery fi ring tables using mechanical calculators. Their time spent at the task was calculated in “girl-years,” or “kilo-girl hours.” It was a cum- bersome, ineffi cient system, but it was about to change, due in no small part to the eff orts of Navy Reserve Lt. j.g. Grace Murray Hopper.

Joining the war eff ort After several years teaching mathe- matics at Vassar College, N.Y., Hopper joined the Navy Reserve in 1943 and was assigned to the Navy’s Bureau of Ships Computation Project at Har- vard University, Mass. She reported to Navy Cmdr. Howard H. Aiken, an intense, no-nonsense offi cer who put her to work on the Mark I, America’s fi rst digital computer. At 50 feet long, 8 feet tall, and 8 feet wide, the Mark I was an im- posing sight. In contrast to other, single-function calculating machines, the Mark I was a general-purpose

54 MILITARY OFFICER MARCH 2014

computer, adaptable to diff erent tasks. Aiken had designed it to help him calculate formulas more effi - ciently, calling it “a lazy man’s idea.” The Mark I was programmed using punched paper tape loops, the holes in the tape representing binary ones and zeros. Mechanical feelers trans- lated the holes into directions for the machine. Hopper called the process of giving the computer instructions “coding” and was not happy when it later became known as programming. Early on, each program was writ- ten from scratch, a constant “reinven-

tion of the wheel” Hopper considered wasteful of time and eff ort. She began using notebooks to record snippets of code that could be reused when need- ed, though they still were entered manually for each program. Hopper called them “subroutines.” Eventually, Aiken assigned her to create a manual for the Mark I, which became the fi rst computer manual ever written. The Mark I proved so much faster and more accurate than manual computa- tion methods that soon its processing time was booked 24 hours a day. No longer did the Navy need to employ

Grace Hopper and other programmers work at the UNIVAC keyboard in 1957.

IMAGES: SMITHSONIAN INSTITUTION; PREVIOUS SPREAD, COMPOSITE BY CANDICE TAYLOR

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