Computer
The word "computer" comes from the word "compute", which means, "to calculate". Hence, people usually consider a computer to be a calculating device that can perform arithmetic operations at high speed. Although the original objective of inventing a computer was to create a fast calculating device, we now define a computer as a device that operates upon data because more than 80% of work done by today's computers is data processing.
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| What is Computer ? | Important Characteristics of Computer |
Data can be anything like
bio-data of applicants when computer is used for short listing candidates for
recruiting; marks obtained by students in various subjects when used for
preparing results; details (name, age, sex, etc.) of passengers when used for
making airline or railway reservations; or number of different parameters when
used for solving scientific research problems, etc. Notice from the examples
that data can be either numerical, non-numerical, or a mixture of both.
A computer is often referred to
as a data processor because it can store, process, and retrieve data whenever
desired. The name data processor is more inclusive because modern computers not
only compute in the usual sense but also perform other functions with data that
flows to and from them.
For example, data processors may
gather data from various incoming sources, merge (process of mixing or putting
together) them all, sort (process of arranging in some sequence — ascending or
descending) them in the desired order, and finally print them in desired
format. Notice that none of these 'operations involves arithmetic computations
in the usual sense but a computer is the most suitable device for performing
them.
The activity of processing data
using a computer is called data processing. Data processing consists of three
sub-activities: capturing input data, manipulating the data, and managing
output results. As used in data processing, information is data arranged in an
order and form that is useful to people receiving it. Hence, data is raw
material used as input to data processing and information is processed data
obtained as output of data processing.
Characteristics of Computer
1. Automatic
An automatic machine works by
itself without human intervention. Computers are automatic machines because
once started on a job, they carry out the job (normally without any human
assistance) until it is finished. However, computers being machines cannot
start themselves and cannot go out and find their own problems and solutions.
We need to instruct a computer using coded instructions that specify exactly
how it will do a particular job. Some of the other characteristics of computers
(such as speed and accuracy) are because they are automatic and work on a problem
without any human intervention.
2. Speed
A computer is a very fast device.
It can perform in a few seconds, the amount of work that a human being can do
in an entire year — if he/she worked clay and night and did nothing else. In
other words, a computer can do in a few minutes what would take a man his
entire lifetime.
While talking about the speed of
a computer we do not talk in terms of seconds or even milliseconds (10-3) but
in terms of microseconds (106), nanoseconds (I0-9), and even picoseconds (10-12).
A powerful computer is capable of performing several billion (109), even
trillion (1012), simple arithmetic operations per second.
3. Accuracy
In addition to being very fast,
computers are very accurate. Accuracy of a computer is consistently high and
the degree of its accuracy depends upon its design. A computer performs every
calculation with the same accuracy.
However, errors can occur in a
computer. These errors are mainly due to human rather than technological
weaknesses. For example, errors may occur due to imprecise thinking by a
programmer (a person who writes instructions for a computer to solve a
particular problem) or incorrect input data. We often refer to computer errors
caused due to incorrect input data or unreliable programs as garbage-in-garbage-out
(GIGO).
4. Diligence
Unlike human beings, a computer
is free from monotony, tiredness, and lack of concentration: It can
continuously work for hours without creatin9 any error and without grumbling.
Hence, computers score over human beings in doing routine type of jobs that
require great accuracy. If ten million calculations have to be performed, a
computer will perform the last one with exactly the same accuracy and speed as
the first one.
5. Versatility
Versatility is one of the most
wonderful things about a computer, One moment it is preparing results of an
examination, next moment it is busy preparing electricity bills, and in
between, it may be helping an office secretary to trace an important letter in
seconds, All that is required to change its talent is to slip in a new program
(a sequence of Instructions for the computer) into it, in brief, a computer is
capable of performing almost any task, if the task can be reduced to a finite
series of logical steps.
6. Power of remembering
As a human being acquires new
knowledge, his/her brain subconsciously select what it feels to be important
and worth retaining in memory. The brain relegates unimportant details to back
of mind or just forgets them. This is not the case with computers. A computer
can store and recall any amount of information because of its secondary storage
(a type of detachable memory) capability. It can retain a piece of information
as long as a user desires and the user can recall the information whenever
required. Even after several years, a user can recall exactly the same
information that he/she had stored in the computer several years ago. A
computer forgets or looses certain information only when a user asks it to do
so. Hence, it is entirely up to the user to make a computer retain or forget
some information.
7. No I. Q.
A computer is not a magical
device. It possesses no intelligence of its own. Its I. Q. is zero, at least
until today. It has to be told what to do and in what sequence. Hence, only a
user determines what tasks a computer will perform. A computer cannot take its
own decision in this regard.
8. No feelings
Computers are devoid of emotions.
They have no feelings and no instincts because they are machines. Although men
have succeeded in building a memory for computer, but no computer possesses the
equivalent of a human heart and soul. Based on our feelings, taste, knowledge,
and experience we often make certain judgements in our day-to-day life whereas,
computers cannot make such judgements on their own. They make judgements based
on the instructions given to them in the form of programs that are written by
us (human beings).
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