"A Walk Through 'Visible Storage'", section 1 of 6, by
From "CORE 2.3", a publication of The Computer History Museum.

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Once upon a time, "computers" were people who computed, not computing machines. Mechanical devices helped make the people more reliable and faster than a reckoner who had only pencil and paper. For instance, the 1895 Swiss "Millionaire"

Photo by Jessica Huynh
was one of the first affordable mass-produced machines that could multiply and divide as well as add and subtract. About 5,000 were produced, and this, one of several in our collection, still works as well as it did the day it was made.

The Comptometer

Photo by Jessica Huynh
was used, mostly by businesses, only for adding and subtracting, but trained operators could tally a column of numbers blazingly fast because all the digits of a single number could be pushed at the same time. If you don't believe this, I'll get my mother, who was a Comptometer operator in the early 1940s, to give you a demonstration. But mechanical calculators were not the genesis of modern electronic computers, they were instead one of many dead ends.


One of the direct ancestors of the computer was the handsome Hollerith census machine,

which was designed to solve a new kind of problem. In 1880, the U.S. census had taken seven years to produce 21,000 pages of data. There was a real danger that the 1890 census might take more than 10 years to count, which would trigger a constitutional crisis because that document requires an "actual enumeration" every decade for allocating seats in the House of Representatives. A young New York engineer named Herman Hollerith won a three- way competition for technology to save the day by using "punched cards" to record and then tabulate the data. It was a great success, and 26,000 pages of data were compiled in only 2 1/2 years.

But as a business, Hollerith's "Tabulating Machine Corporation" had a less than stellar business plan: they had only one product, and one major customer that bought every 10 years. Hollerith gradually made the transition to supplying general office machines based on the same technology, and diversified the product line by merging with a computing scale company and a time clock company, calling the result CTR ("Computing-Tabulating- Recording") Company. Hollerith's health was failing and he retired in 1911 with about a million dollars, which was serious money in those days.

It took a consummate salesman fired from National Cash Register in 1911 to rename the company "IBM" in 1924 and create the dominant force in computers for many decades. That salesman was T.J. Watson,

Photo by Yosuf Karsh
and he and his son Tom Watson, Jr. ran the company for an astounding 60 years between them.

IBM started before the invention of the electronic computer. Its products were electro- mechanical machines designed primarily for office automation, based on Hollerith's punched card. Here are machines used for punching,

Photo by Michael Dubinsky
copying, and sorting,

Photo by Michael Dubinsky
the cards.

IBM's business model was brilliant: instead of selling machines, they leased them and so created a recurring revenue stream. And, they sold the "razor" for your "shaver" as well: in 1930 IBM sold 3 billion of those punched paper cards, accounting for 10% of their revenue and 35% of their profit.

The drive toward fast electronic computers with no moving parts was natural and unstoppable, but some people still enjoyed tinkering with homebuilt computers made out of more unusual technology. Here are three examples, constructed as early as 1932, by Prof. Derrick Lehmer at the University of California at Berkeley. One is built from bicycle chains and screws, one from industrial gears and toothpicks, and one from 16mm film strips and wooden bobbins. Lehmer's Sieves,

Photo by Jessica Huynh
three very different "computers," solve the same problem-finding prime numbers using the Sieve of Eratosthenes-and dramatically demonstrate that an algorithm and the device that executes it are very different indeed.

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