CHAPTER SEVEN
T Information
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arly computers were really just mechanical calculators. They used turning shafts and gears to perform routine arithmetic. Numbers were represented by the position of the shafts and gears. Even a person skilled in the use of an ancient invention called the abacus could compete with a mechanical calculator. Mechanical calculators were already common in the first fifty years of the twentieth century. Many of them were driven by motors that used electricity as their source of energy. Still, no one thought of using variations in electricity to represent numbers instead of to power a mechanical device. By the 1930s, some telephone systems used automatic electric switches to connect phone lines for making calls. A telephone call transferred information by human voice, but the electric device that did the connecting was not a computer. Nevertheless, it was devices such as these that got Claude Shannon thinking about electricity. Shannon was a university student from Michigan who studied both electrical engineering and mathematics. This was the perfect combination for the founding father of the electronic communications age and the advent of the computer and telecommunications industries. Shannon realized that the switching of phone lines could be represented by purely mathematical concepts. He also saw that all
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Great Inventions of the 20th Century