The Computer
One of the greatest inventions of the 20th
century is the computer. A computer is a device that is used to store and
process information and to perform calculations.
A computer can be designed to
process almost any type of information. Computers are found in most
businesses and industries. They are used in schools,
hospitals and libraries. Computers are used by scientists and mathematicians,
by doctors and lawyers, and by many other people
in many kinds of work.
Computers can do practically anything
— except think. Computers can only act on instructions which are entered
into their systems; this set of instructions is called
a program. A programmer enters instructions into the computer. These instructions
are received in a storage unit called the memory. When information is needed,
instructions and information are processed by the
computer. This information is shown on a screen or printed on paper by a
printer or an automatic typewriter.
The computer was not invented
by just one person. As early as the 1600's, scientists and mathematicians
developed devices for calculations. In the mid-1800's,
several machines were developed to calculate numbers by following a set of
instructions. But it wasn't until the 1930's and 1940's that electronic
computers were designed and built which could compute
facts the microchip
in just seconds. The first modern computer was built
in 1946; it was known as ENIAC. But this first electronic computer was
huge—it required an entire room to hold it.
In 1947, the transistor was invented.
With transistors, computers could be made much smaller and more powerful
than ENIAC.
But the real breakthrough in computers
came in the early 1970's, with the invention of the microchip. A microchip
is about the size of a fingernail. The whole microchip
unit is called a microprocessor. The microchip holds most of the important
parts of a computer.
Because of the microchip, computers
can be made much smaller and cheaper. The microchip makes it possible to
produce the many microcomputers used today, The programs
for microcomputers are called software. The microcomputer itself is
called hardware.
Today, microcomputers are used
to make everything from video games to space rockets.
