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Babbage managed to build only a simple model because the craftsmen of the day were unable to machine the precise parts required by the contraption. But the temperamental genius soon had a bolder concept. He called it the Analytical Engine. Even more complex than its predecessor, it had all the essentials of a modern computer: a logic center, or what Babbage called the "mill," which manipulated data according to certain rules; a memory, or "store," for holding information; a control unit for carrying out instructions; and the means for getting data into and out of the machine. Most important of all, its operating procedures could be changed at will: the Analytical Engine was programmable.
Babbage worked obsessively on his machine for nearly 40 years. Presumably he was the world's first computer "nerd." Until his death in 1871, he ground out more and more sketches. The Analytical Engine became hopelessly complicated. It required thousands of individual wheels, levers and belts, all working together in exquisite precision. Few people understood what he was doing, with the notable exception of Lord Byron's beautiful and mathematically gifted daughter, Ada, the Countess of Lovelace, who became Babbage's confidante and public advocate. When the government cut off funds for the Analytical Engine, she and Babbage tried devising a betting system for recouping the money at the track. They lost thousands of pounds.
The Analytical Engine was never built. It would have been as big as a football field and probably needed half a dozen steam locomotives to power it. But one of its key ideas was soon adapted. To feed his machine its instructions, Babbage planned to rely on punched cards, like those used to control color and designs in the looms developed by the French weaver Joseph Marie Jacquard. Ada poetically described the scheme this way: "The Analytical Engine weaves algebraical patterns just as the Jacquard loom weaves flowers and leaves."
In the U.S., a young engineer named Herman Hollerith persuaded the Census Bureau to try the punched-card idea during the forthcoming 1890 census. Such personal information as age, sex, marital status and race was encoded on cards, which were read by electric sensors, and tabulated. Hollerith's equipment worked so well that the Census Bureau's clerks occasionally shut it off to protect their sinecures. Soon punched cards were widely used in office machinery, including that made by a small New York firm that absorbed Hollerith's company and became International Business Machines.