Sam Anderson, age 13, of Prescott, Ariz., for his question:
WHO INVENTED THE COMPUTER?
An English mathematician named Charles Babbage developed the idea of a mechanical digital computer in the early 1830s. He designed and tried to build a complicated machine called an analytical engine.
Unfortunately Babbage wasn't able to complete his machine. But computers today are based on many of the principles which Babbage designed.
It took almost a hundred years to do the~job. In 1930, an American electrical engineer named Vannevar Bush built the first analog computer. He called his machine a differential analyzer. During World War II engineers developed electronic analog computers to help aim anti aircraft guns.
A Harvard University professor named Howard Aiken completed the first digital computer in 1944. He called his machine Mark I. Both mechanical and electrical devices were used to control the operation of Mark I.
The most important computer advancement came in the 1940s with the work of an American mathematician named John von Neumann. He developed the idea of storing the computer program in the machine's memory.
In 1946, the engineers at the University of Pennsylvania built the first digital computer controlled by vacuum tubes. They called it the Electronic Numerical Integrator and Computer, or ENIAC for short.
Then in 1951 the same team developed UNIVAC I, the first of a variety of computers that were mass produced during the 1950s.
After mass production started, improvements in design and operation followed. New computers worked faster and were more reliable than earlier models. The new models were able to perform operations in one tenth the time it took earlier models.
During the 1960s, manufacturers developed a way of operating computers called multi programming or time sharing. This method makes it possible for many users to "share" a computer at the same time.
A computer can handle more than one problem at a time because its CPU, or central processing unit, operates much faster than its peripheral equipment. The CPU works on one user's problem while the peripheral equipment processes input and output data for other users.
Computer engineers have also developed peripheral equipment that can be linked with a distant computer by telephone lines. Such remote terminals, along with time sharing methods, permit many people at wide spread locations to use a single computer.
By 1970, about 75,000 computers were in use in the United States. By 1980, this number had grown to more than 300,000.