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CHIPS Articles: "Amazing Grace"

"Amazing Grace"
By CHIPS Magazine - January-March 2012
A pioneer in programming languages and technology development, Rear Adm. Grace Hopper was instrumental in bringing computer technology to Navy desktops and individuals. Hopper had an uncanny ability to predict the IT trends of the future. Many of her predictions came true during her lifetime as industry built more powerful, more compact machines.

Some of her more innovative ideas included using computers for predicting weather patterns and ocean waves, tracking the life cycle of crop eating locusts, and managing water reserves. In 1986, President Ronald Reagan awarded Hopper the prestigious National Medal of Technology at a ceremony in the White House. But Hopper considered her highest award to have been "the privilege and honor of serving very proudly in the United States Navy."

The Mark I – the impressive beast

The Mark I, programmed by pre-punched paper tape, could perform addition, subtraction, multiplication, division and reference to previous results. It had special subroutines for logarithms and trigonometry and used 23 decimal place numbers. Data was stored and counted mechanically using 3,000 storage wheels, 1,400 rotary dial switches and 500 miles of wire. Because of its electromagnetic relays it was considered a relay computer.

Output was displayed on an electric typewriter. The Mark I took three to five seconds to calculate a multiplication equation. It weighed five tons and contained almost 760,000 separate pieces. Lt. j.g. Grace Brewster Hopper was enchanted with its performance, until the UNIVAC I came along — operating a thousand times faster. The Navy used the Mark I until 1959.

As a child growing up in New York City, Hopper was "good with gadgets." When Hopper first saw the Mark I, she couldn't wait to start taking it apart to see how it worked. Remarking on the Mark I, Hopper said, "That was an impressive beast. She was fifty-one feet long, eight feet high and five feet deep."

Lt. j.g. Grace Brewster Hopper working at the Bureau of Ordnance Computation Project, Harvard University, Cambridge, Mass., January 1946. Photo courtesy of the Defense Visual Information Center. For more information about Hopper, visit the Naval History and Heritage Command website at and search under “Grace Hopper.”
Lt. j.g. Grace Brewster Hopper (seated second from right) with Cmdr. Howard H. Aiken (seated center), who developed the first large scale digital computer, officially called the IBM automatic sequence controlled calculator, more commonly called the Harvard Mark I. The posed photograph, with other members of the Bureau of Ordnance Computation Project, was taken in front of the Mark I computer. Hopper started as the first programmer in 1944 on the Mark I (IBM ASCC). As a programmer, she used the Mark I to compute firing tables for weapons and then wrote them into a series of instructions for the computer. In 1946 she published a book, “A Manual of Operations for the Automatic Sequence Controlled Calculator.” Hopper continued to work on the Mark II and Mark III. Photo taken at Harvard University, Cambridge, Mass., January 1944. Photo courtesy of Defense Visual Information Center.
The Mark I. Photo courtesy of the Computer Science Department of Virginia Polytechnic Institute and State University.
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