HISTROY OF A computer might be described with deceptive simplicity as “an apparatus that performs routine calculations automatically.” Such a definition would owe its deceptiveness to a naive and narrow view of calculation as a strictly mathematical process. In fact, calculation underlies many activities that are not normally thought of as mathematical. Walking across a room, for instance, requires many complex, albeit subconscious, calculations. Computers, too, have proved capable of solving a vast array of problems, from balancing a checkbook to even—in the form of guidance systems for robots—walking across a room.
Before the true power of computing could be realized, therefore, the naive view of calculation had to be overcome. The inventors who laboured to bring the computer into the world had to learn that the thing they were inventing was not just a number cruncher, not merely a calculator. For example, they had to learn that it was not necessary to invent a new computer for every new calculation and that a computer could be designed to solve numerous problems, even problems not yet imagined when the computer was built. They also had to learn how to tell such a general problem-solving computer what problem to solve. In other words, they had to invent programming.
They had to solve all the heady problems of developing such a device, of implementing the design, of actually building the thing. The history of the solving of these problems is the history of the computer. That history is covered in this section, and links are provided to entries on many of the individuals and companies mentioned. In addition, see the articles computer science and supercomputer.
The abacus
The earliest known calculating device is probably the abacus. It dates back at least to 1100 BCE and is still in use today, particularly in Asia. Now, as then, it typically consists of a rectangular frame with thin parallel rods strung with beads. Long before any systematic positional notation was adopted for the writing of numbers, the abacus assigned different units, or weights, to each rod. This scheme allowed a wide range of numbers to be represented by just a few beads and, together with the invention of zero in India, may have inspired the invention of the Hindu-Arabic number system. In any case, abacus beads can be readily manipulated to perform the common arithmetical operations—addition, subtraction, multiplication, and division—that are useful for commercial transactions and in bookkeeping.
The abacus is a digital device; that is, it represents values discretely. A bead is either in one predefined position or another, representing unambiguously, say, one or zero.
Charles Babbage was an English mathematician and inventor: he invented the cowcatcher, reformed the British postal system, and was a pioneer in the fields of operations research and actuarial science. It was Babbage who first suggested that the weather of years past could be read from tree rings. He also had a lifelong fascination with keys, ciphers, and mechanical dolls.
While working on the Difference Engine, Babbage began to imagine ways to improve it. Chiefly he thought about generalizing its operation so that it could perform other kinds of calculations. By the time the funding had run out in 1833, he had conceived of something far more revolutionary: a general-purpose computing machine called the Analytical Engine.
Lady Lovelace, the first programmer
The distinction between calculator and computer, although clear to Babbage, was not apparent to most people in the early 19th century, even to the intellectually adventuresome visitors at Babbage’s soirees—with the exception of a young girl of unusual parentage and education.
Herman Hollerith’s census tabulator
The U.S. Constitution mandates that a census of the population be performed every 10 years. The first attempt at any mechanization of the census was in 1870, when statistical data were transcribed onto a rolling paper tape displayed through a small slotted window. As the size of America’s population exploded in the 19th century and the number of census questions expanded, the urgency of further mechanization became increasingly clear.
After graduating from the Columbia University School of Mines, New York City, in 1879, Herman Hollerith obtained his first job with one of his former professors, William P. Trowbridge, who had received a commission as a special agent for the 1880 census. It was while employed at the Census Office that Hollerith first saw the pressing need for automating the tabulation of statistical data.
Over the next 10 years Hollerith refined his ideas, obtaining his first patent in 1884 for a machine to punch and count cards. He then organized the health records for Baltimore, Maryland, for New York City, and for the state of New Jersey—all in preparation for winning the contract to tabulate the 1890 U.S. Census. The success of the U.S. census opened European governments to Hollerith’s machines. Most notably, a contract with the Russian government, signed on December 15, 1896, may have induced him to incorporate as the Tabulating Machine Company on December 5, 1896.
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