PC Hardware

The Abacus

The abacus, shown in Figure 1.1, is a calculator; its first recorded use was circa 500 B.C. The Chinese used it to add, subtract, multiply, and divide. But the abacus was not unique to the continent of Asia; archeological excavations have revealed an Aztec abacus in use around 900 or 1000 A.D.

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Figure 1.1 The first computer

The Analytical Engine (A Pre-Electronic Computer)

The first mechanical computer was the analytical engine, conceived and partially constructed by Charles Babbage in London, England, between 1822 and 1871. It was designed to receive instructions from punched cards, make calculations with the aid of a memory bank, and print out solutions to math problems. Although Babbage lavished the equivalent of $6,000 of his own money-and $17,000 of the British government's money-on this extraordinarily advanced machine, the precise work needed to engineer its thousands of moving parts was beyond the ability of the technology of the day to carry out. It is doubtful whether Babbage's brilliant concept could have been realized using the available resources of his own century. But if it had been, it seems likely that the analytical engine could have performed the same functions as many early electronic computers.

The First Electrically Driven Computer

The first computer designed expressly for data processing was patented on January 8, 1889, by Dr. Herman Hollerith of New York. The prototype model of this electrically operated tabulator was built for the U. S. Census Bureau and computed results in the 1890 census.

Using punched cards containing information submitted by respondents to the census questionnaire, the Hollerith machine made instant tabulations from electrical impulses actuated by each hole. It then printed out the processed data on tape. Dr. Hollerith left the Census Bureau in 1896 to establish the Tabulating Machine Company to manufacture and sell his equipment. The company eventually became IBM, and the 80-column punched card used by the company, shown in Figure 1.2, is still known as the Hollerith card.

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Figure 1.2 Typical 80-character punched card