Computers Essay, Research Paper

Computers

Computer are electronic device that can receive a set of instructions,

or program, and then carry out a program by performing calculations on numbered

data or by compiling and correlating other forms of information. The old world

of technology could not believe about the making of computers. Different types

and sizes of computers find uses throughout our world in the handling of data

including secret governmental files and making banking transactions to private

household accounts. Computers have opened up a new world in manufacturing

through the developments of automation, and they have made modern communication

systems. They are great tools in almost everything you want to do research and

applied technology, including constructing models of the universe to producing

tomorrow’s weather reports, and their use has in itself opened up new areas of

development. Database services and computer networks make available a great

variety of information sources. The same new designs also make possible ideas of

privacy and of restricted information sources, but computer crime has become a

very important risk that society must face if it would enjoy the benefits of

modern technology. Two main types of computers are in use today, analog and

digital, although the term computer is often used to mean only the digital type.

Everything that a digital computer does is based on one operation the ability to

determine if a switch, or gate is open or closed. That is, the computer can

recognize only two states in any of its microscopic circuits on or off, high

voltage or low voltage, or?in the case of numbers?0 or 1. The speed at which the

computer performs this simple act, however, is what makes it a marvel of modern

technology. Computer speeds are measured in megaHertz, or millions of cycles per

second. A computer with a “clock speed” of 10 mHz?a fairly representative speed

for a microcomputer?is capable of executing 10 million discrete operations each

second. Business microcomputers can perform 15 to 40 million operations per

second, and supercomputers used in research and defense applications attain

speeds of billions of cycles per second. Digital computer speed and calculating

power are further enhanced by the amount of data handled during each cycle. If a

computer checks only one switch at a time, that switch can represent only two

commands or numbers; thus ON would symbolize one operation or number, and OFF

would symbolize another. By checking groups of switches linked as a unit,

however, the computer increases the number of operations it can recognize at

each cycle. The first adding machine, a precursor of the digital computer, was

devised in 1642 by the French philosopher Blaise Pascal. 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. Analog computers began to be built at the start

of the 20th century. Early models calculated by means of rotating shafts and

gears. Numerical approximations of equations too difficult to solve in any other

way were evaluated with such machines. During both world wars, mechanical and,

later, electrical analog computing systems were used as torpedo course

predictors in submarines and as bombsight controllers in aircraft. Another

system was designed to predict spring floods in the Mississippi River Basin. In

the 1940s, Howard Aiken, a Harvard University mathematician, created what is

usually considered the first digital computer. This machine was constructed from

mechanical adding machine parts. The instruction sequence to be used to solve a

problem was fed into the machine on a roll of punched paper tape, rather than

being stored in the computer. In 1945, however, a computer with program storage

was built, based on the concepts of the Hungarian-American mathematician John

von Neumann. The instructions were stored within a so-called memory, freeing the

computer from the speed limitations of the paper tape reader during execution

and permitting problems to be solved without rewiring the computer. The rapidly

advancing field of electronics led to construction of the first general-purpose

all-electronic computer in 1946 at the University of Pennsylvania by the

American engineer John Presper Eckert, Jr. and the American physicist John

William Mauchly. (Another American physicist, John Vincent Atanasoff, later

successfully claimed that certain basic techniques he had developed were used in

this computer.) Called ENIAC, for Electronic Numerical Integrator And Computer,

the device contained 18,000 vacuum tubes and had a speed of several hundred

multiplications per minute. Its program was wired into the processor and had to

be manually altered.

The use of the transistor in computers in the late 1950s marked the advent

of smaller, faster, and more versatile logical elements than were possible with

vacuum- tube machines. Because transistors use much less power and have a much

longer life, this development alone was responsible for the improved machines

called second-generation computers. Components became smaller, as did

intercomponent spacings, and the system became much less expensive to build.

Different types of peripheral devices?disk drives, printers, communications

networks, and so on?handle and store data differently from the way the computer

handles and stores it. Internal operating systems, usually stored in ROM memory,

were developed primarily to coordinate and translate data flows from dissimilar

sources, such as disk drives or co-processors (processing chips that perform

simultaneous but different operations from the central unit). An operating

system is a master control program, permanently stored in memory, that

interprets user c ommands requesting various kinds of services, such as display,

print, or copy a data file; list all files in a directory; or execute a

particular program. A program is a sequence of instructions that tells the

hardware of a computer what operations to perform on data. Programs can be built

into the hardware itself, or they may exist independently in a form known as

software. In some specialized, or “dedicated,” computers the operating

instructions are embedded in their circuitry; common examples are the

microcomputers found in calculators, wristwatches, automobile engines, and

microwave ovens. A general-purpose computer, on the other hand, contains some

built-in programs (in ROM) or instructions, in a chip, but it depends on

external programs to perform useful tasks. Once a computer has been programmed,

it can do only as much or as little as the software controlling it at any given

moment enables it to do. Software in widespread use includes a wide range of

applications programs?instructions to the compute r on how to perform various

tasks.