A Computer is an electronic device that can receive a set of instructions, or
program, and then carry out this program by performing calculations on numerical
data or by compiling and correlating other forms of information. The modern
world of high technology could not have come about except for the development of
the computer. Different types and sizes of computers find uses throughout
society in the storage and handling of data, from secret governmental files to
banking transactions to private household accounts. Computers have opened up a
new era in manufacturing through the techniques of automation, and they have
enhanced modern communication systems. They are essential tools in almost every
field of research and applied technology, from constructing models of the
universe to producing tomorrow's weather reports, and their use has in itself
opened up new areas of conjecture. Database services and computer networks make
available a great variety of information sources. The same advanced techniques
also make possible invasions of privacy and of restricted information sources,
but computer crime has become one of the many risks that society must face if it
would enjoy the benefits of modern technology. (Gulliver 12-15) Imagine a world
without computers. That would mean no proper means of communicating, no
Internet, no video games. Life would be extremely difficult. Adults would have
to store all their office work paper and therefore take up an entire room.
Teenagers would have to submit course-works and projects hand-written. All
graphs and diagrams would have to be drawn neatly and carefully. Youngsters
would never have heard of 'video-games' and will have to spend their free time
either reading or playing outside with friends. But thanks to British
mathematicians, Augusta Ada Byron and Charles Babbage, our lives are made a lot
easier. (Malone 5-6) There are two main types of computers that are in use
today, analog and digital computers, although the term computer is often used to
mean only the digital type. Analog computers exploit the mathematical similarity
between physical interrelationships in certain problems, and employ electronic
or hydraulic circuits to simulate the physical problem. Digital computers solve
problems by performing sums and by dealing with each number digit by digit. (Cringley
28-30) Hybrid computers are those that contain elements of both analog and
digital computers. They are usually used for problems in which large numbers of
complex equations, known as time integrals, are to be computed. Data in analog
form can also be fed into a digital computer by means of an analog- to-digital
converter, and the same is true of the reverse situation. (Cringley 31-32) The
French philosopher Blaise Pascal devised the first adding machine, a precursor
of the digital computer, in 1642. This device employed a series of ten-toothed
wheels, each tooth representing a digit from 0 to 9. The wheels were connected
so that numbers could be added to each other by advancing the wheels by a
correct number of teeth. In the 1670s the German philosopher and mathematician
Gottfried Wilhelm von Leibniz improved on this machine by devising one that
could also multiply. The French inventor Joseph Marie Jacquard, in designing an
automatic loom, used thin, perforated wooden boards to control the weaving of
complicated designs. During the 1880s the American statistician Herman Hollerith
conceived the idea of using perforated cards, similar to Jacquard's boards, for
processing data. Employing a system that passed punched cards over electrical
contacts, he was able to compile statistical information for the 1890 U.S.
census. (Hazewindus 44-48) Also in the 19th century, the British mathematician
and inventor Charles Babbage worked out the principles of the modern digital
computer. He conceived a number of machines, such as the Difference Engine, that
were designed to handle complicated mathematical problems. Many historians
consider Babbage and his associate, the British mathematician Augusta Ada Byron
(Lady Lovelace, 1815-52), the daughter of the English poet Lord Byron, the true
inventors of the modern digital computer. The technology of their time was not
capable of translating their sound concepts into practice; but one of their
inventions, the Analytical Engine, had many features of a modern computer. It
had an input stream in the form of a deck of punched cards, a "store"
for saving data, a "mill" for arithmetic operations, and a printer
that made a permanent record. (Hazewindus 56-58) Late in the 1960s the
integrated circuit, or IC, was introduced, making it possible for many
transistors to be fabricated on one silicon substrate, with inter- connecting
wires plated in place. The IC resulted in a further reduction in price, size,
and failure rate. The microprocessor became a reality in the mid-1970s with the
introduction of the large-scale integrated (LSI) circuit and, later, the very
large scale integrated (VLSI) circuit, with many thousands of interconnected
transistors etched into a single silicon substrate. To return, then, to the
"switch-checking" capabilities of a modern computer: computers in the
1970s generally were able to check eight switches at a time. That is, they could
check eight binary digits, or bits, of data, at every cycle. A group of eight
bits is called a byte, each byte containing 256 possible patterns of ONs and
OFFs (or 1's and 0's). Each pattern is the equivalent of an instruction, a part
of an instruction, or a particular type of datum, such as a number or a
character or a graphics symbol. The pattern 11010010, for example, might be
binary data-in this case, the decimal number 210 (see NUMBER SYSTEMS)-or it
might tell the computer to compare data stored in its switches to data stored in
a certain memory-chip location. (Gulliver 30-33) The development of processors
that can handle 16, 32, and 64 bits of data at a time has increased the speed of
computers. The complete collection of recognizable patterns-the total list of
operations-of that a computer is capable is called its instruction set. Both
factors-number of bits at a time, and size of instruction sets-continue to
increase with the ongoing development of modern digital computers. (Dolotta
7-13) Major changes in the use of computers have developed since it was first
invented. Computers have expanded, via telephone lines, into vast nation-wide,
or worldwide, networks. At each extremity of the network is a terminal device,
or even a large computer, which can send jobs over the wire to the central
computer at the hub of the network. The central computer performs the
computation or data processing and sends the results over the wire to any
terminal in the network for printing. Some computer networks provide a service
called time-sharing. This is a technique in which software shifts the computer
from one task to another with such timing that it appears to each user at a
terminal that he has exclusive use of the computer. (Malone 59-62) Other
developments in the industry are aimed at increasing the speed at which data can
be transmitted. Improvements are being made continually in modems and in the
communications networks. Some public data networks support transmission of
56,000 bits per second (bps), and modems for home use are capable of as much as
56kbps. (Chposky 40-42) CD's have developed a lot over the past decade. At
first, they were used only for music. Now, there are CD's from which we can play
PC games and watch movies. The games at present are usually 3D. This means that
the game seems almost life-like or virtual. One can spend hours playing games on
CD because they are addictive. This is one of the main disadvantages of computer
games, because the person prevents himself or herself from doing anything
educational or engaging themselves in any physical activities. Another common
disadvantage is that playing too much on the computer can cause bad eyesight.
But there are a few educational games for young children to help them learn and
understand things better. Games may not be all that good for an individual, but
if seen how they are programmed one will realize that it is not all easy to
program a game. (Gulliver 100-105) A few years ago, if one were bored, they
would usually go to a video shop and rent a movie. Now one can rent Movie CD's
and play them on the computer and special Movie CD players, which are also
installed. We have made many advantages though the years, and we are still
making more in leaps and bounds. Computers have become a major part of our
lives, and will continue to be forever. 
Bibliography
Chposky, James. Blue Magic. New York: Facts on File Publishing. 1988.
Cringley, Robert X. Accidental Empires. Reading, MA: Addison Wesley Publishing,
1992. Dolotta, T.A. Data Processing: 1940-1985. New York: John Wiley & Sons,
1985. Gulliver, David. Silicon Valley and Beyond. Berkeley, Ca: Berkeley Area
Government Press, 1981. Hazewindus, Nico. The U.S. Microelectronics Industry.
New York: Pergamon Press, 1988. Malone, Michael S. The Big Scare: The U.S.
Computer Industry. Garden City, NY: Doubleday & Co., 1985.