COMPUTER INTRODUCTION
“Computer is an
electronic device which is capable of receiving information (data) in a
particular form and of performing a sequence of operations in accordance with a
predetermined but variable set of procedural instructions (program) to produce
a result in the form of information or signals”.
“A computer device is an
electronic device that manipulates information or data. It has the ability to
store, retrieve and process data. You can use a computer to type documents,
send email and browse the internet. You can also use it to handle spreadsheets,
accounting, database management, presentations, games and more”.
A computer is a
programmable machine designed to perform arithmetic and logical operations
automatically and sequentially on the input given by the user and gives the
desired output after processing. Computer components are divided into two major
categories namely hardware and software. Hardware is the machine itself and its
connected devices such as monitor, keyboard, mouse etc. software are the set of
programs that make use of hardware for performing various functions.
Charles Babbage is called the ‘Father’ of the computer. The first
mechanical computer designed by Charles Babbage was called Analytical Engine. It uses read-only memory in the form of punch
cards.
Four Functions about computer
are:
Accepts
data
|
Input
|
Process
data
|
Processing/Mill
|
Produces
output
|
Output
|
Stores
results
|
Storage
|
1. Input (Data):
Input is the raw
information entered into a computer from the input devices. It is the
collection of letters, numbers, images etc.
2. Process:
Process is the operation
of data as per given instruction. It is totally internal process of the
computer system.
3. Output:
Output is the processed
data given by computer after data processing output is also called as result.
We can save these results in the storage devices for the future use.
3.1.1 CHARACTERISTICS OF
COMPUTERS
Much of the world runs
on computers and computers profoundly changed human life mostly for better. Characteristics of computer are:
1. Speed:
A computer is a very fast
device. It can carry out instructions at a very high speed obediently,
uncritically and without exhibiting any emotions. It can perform in a few
seconds the amount of work that a human being can do in an entire year – if he
work day and night and is nothing else. A powerful computer is capable of
performing about 3-4 million simple instructions per second.
Some calculation that
would have taken hours and days to complete otherwise, can be completed in a
few seconds using the computer. The speed of computer is calculated in MHz,
that is one million instructions per second.
2. Accuracy:
Accuracy of a computer is
consistently high and the degree of accuracy of a particular computer depends
on the instructions and the type of processor. But for a particular computer,
each and every calculation is performed. For example, the computer accurately
give the result of division of any number up to 10 decimal points.
3. Versatility:
Versatility is one of the
most wonderful things about computer. Multiprocessing features of computer
makes it quiet versatile in nature. One moment, it is preparing the results of
particular examination, the next moment it is busy preparing electricity bills
and in between it may be helping an office secretary to trace an important
latter in second.
It can perform different
types of tasks with same ease. All that is required to change its talent is to
slip in a new program into it. Briefly, a computer is capable of performing
almost any task provided that the task can be reduced to a series of logical
steps.
4.
Reliability:
Computer provide very
high speed accompanied by an equality high level for reliability. Thus
computers never make mistakes of their own accord.
5.
Power
of Remembering:
A computer can store and
recall any amount of information because of its secondary storage capability.
Every piece of information can be retain as long as desired by the user and it
can be recalled information almost instantaneously. Even after several years,
the information recalled will be as accurate as on the day when it was fed to
the computer.
6.
Common
Data Used:
One time can be involved
in several different procedures or accessed, update and inspected by a number
of different users. This can hinder the work of those who need access to data.
As the time is changing, more and more facilities are being added to the computers
they can perform but in practical life many tasks are limited to these basic
operations.
7.
Diligence:
The computer is a
machine, does not suffer from the human traits of tiredness. Nor does it loses
concentration even after working continuously for a long time.
This characteristics is
especially useful for those jobs where sane tasks is done again and again. It
can perform long and complex calculations with same speed and accuracy from the
start till the end.
8.
Storage:
The computers have a lot
of a storage devices which can store a tremendous amount of data. Data storage
is essential function of the computer. Second storage devices like floppy disk
can store a large amount of data permanently.
0
or 1 - 1 Bit
4
Bits - 1 Nibble or Nano Byte
2
Nibbles or 8 Bits - 1 Byte
1024
Bytes - 1KB (Kilo Byte)
1024
KB - 1 MB (Mega Byte)
1024
MB - 1 GB (Giga Byte)
1024
GB - 1 TB (Tera Byte)
1024
TB - 1 HB (Hexa Byte)
1024
HB - 1 PB (Peta Byte)
1024
PB - 1 ZB (Zetta Byte)
APPLICATION OF COMPUTERS
Computers have
proliferated into various areas of our lives. For a user, computer is a tool
that provides the desired information, whenever needed. You may use computer to
get information about the reservation of tickets (railways, airplanes and
cinema halls) books in a library, medical history of a person, a place in a map
or the dictionary meaning of a word. The information may be presented to you in
the form of text, images, videos clips etc.
Education Computers are
extensively used, as a tool and as an aid, for imparting education. Educators
use computers to develop computer-based training packages, to provide distance
education using the e-learning software and to conduct online examinations.
Researchers use computers to get easy access to conference and journal details
and to get global access to the research material.
·
The uses of computer provide a tool
in the Education system known as CBE (Computer Based Education).
·
CBE involves Control, Delivery and
Evaluation of learning.
·
The computer education is very
familiar and rapidly increasing the graph of computer students.
·
There are number of methods in
which educational institutions can due computer to educate the students.
·
It is used to prepare a database
about student performance and analysis are carried out.
1. Entertainment:
Computer have a major
impact o the entertainment industry. The user can donload and view movies, play
games, chat, book tickets for cinema halls, use multimedia for making movies,
incorporate visual and sound effects using computers etc. the users can also
listen to music, download and share music, create, music using computers etc.
2. Sports:
A computer can be used to
watch a game, view the scores, improve the game, play games (like chess. etc)
and create games. They are also used for the purpose of training players.
3. Advertising:
Computer is a powerful
advertising media. Advertisement can be displayed on different websites,
electronic-mails can be sent and reviews of a product by different customers
can be posted. Computers are also used to create an advertisement using the
visual and the sound effects. For the advertisers, computer is a medium via
which the advertisements can be viewed globally. Web advertisement has become a
significant factor in the marketing plans of almost all companies. In fact, the
business model of Google is mainly dependent on web advertisement for
generating revenues.
4. Medicine:
Medical researchers and
practitioners use computers to access information about the advances in medical
research or to take opinion of doctors globally. The medical history of
patients is stored in the computers. Computers are also an integral part of
various kinds of sophisticated medical equipments like ultrasound machine. CAT
scan machine, MRI scan machine etc. computers also provide assistance to the
medical surgeons during critical surgery operations like laparoscopic
operations etc.
5. Science and Engineering:
Scientists and engineers
use computers for performing complex scientific calculations, for designing and
making drawings (CAD/CAM applications) and also for stimulating and testing the
designs. Computers are used for storing the complex data, performing complex
calculations and for visualizing 3-dimensional objects. Complex scientific
applications like the launch of the rockets, space exploration etc. are not
possible without the computers.
6. Government:
The government uses
computers to manage its own operations and also for e-governance. The websites
of the different government departments provide information to the users.
Computers are used for the filling of income tax return, paying taxes, online
submission of water and electricity bills for the access of land record
details, etc. the police department uses computers to search for criminals
using fingerprint matching etc.
7. Home:
Computers have now become an integral part of
home equipment. At home, people use computers to play games, to maintain the
home, accounts, for communicating with friends and relatives via Internet, for
paying bills, for education and learning etc. microprocessors are embedded in
household utilities, like washing machines, TVs, food processors, home
theatres, security devices etc.
8. Military:
Computers are largely
used in defense. Modern tanks, missiles, weapons etc. employ computerized
control systems. Some military areas where a computer has been used are:
·
Missile Control
·
Military Communication
·
Military operation and planning
·
Smart Weapons
9. Banking:
Today Banking is almost
totally dependent on computer.
Banks provide following
facilities:
·
Banks online accounting facility,
which includes current balances, deposits, overdrafts, interest charges, shares
and trustee records.
·
ATM machine are making it even
easier for customer s to deal with banks.
10. Business:
The computer’s characteristic
as high speed of calculation, diligence, accuracy, reliability or versatility
has made it an integrated part in all business organizations.
Computer is used in business
organization for:
·
Payroll Calculations
·
Budgeting
·
Sales Analysis
·
Financial forecasting
·
Managing employees database
·
Maintenance of stocks etc.
11. Communications:
Communication means to
convey a message, an idea, a picture or speech that is received and understood
clearly and correctly by the person for whom it is meant. Some main areas in
this category are:
·
E-mail
·
Chatting
·
Usenet
·
FTP
·
Telnet
·
Video-conferencing
Disadvantages of Computers:
·
Computer is highly dependent on the
quality of input data fed to it. Though computers are very fast in tasks that
are pre-programmed, it lacks the ability of human brain to detect and correct
errors that it is not specifically programmed to do.
·
The task of programming a computer
for a computer application is very costly and the time consuming. This reduces
the utility of computers for applications that are non-repetitive.
·
Computer systems are rather rigid.
Once a computers system is designed and programmed, making even minor
corrections or improvements can be quite costly and time consuming. For this
reason a great care is required in design and development of computer systems.
·
Computers require use of
sophisticated and support facilities. For example, a person solving a problem
of maths using just a pen and paper can carry these with him or her anywhere
with ease. However, if the same problem is to be solved using a computer, the
person will not only access will not only need access to suitable computer, it
will also be necessary to have the required software and suitable electric
power to run the computer.
·
The cost of computer and associated
equipments is falling steadily. Still these equipments are and continue to be
much more costly as compared to annual processing equipments like pen and
pencil./ also technological complexity of these equipments as compared to
equipments of manual information processing.
·
Use of computers require additional
infrastructure, such as power supply and software back up. This increases the
chances of problems due to failure of infrastructure. For example, a computer
will not work where there is no electric power supply. Even a laptop with a
battery will work without power supply only
for a limited period.
·
Failures of computer system can be
more serious and difficult to correct. For example, one scratch on a hard disk
can make the complete data on the disk inaccessible. In comparison, manual
system faults have comparatively limited impact. One page torn from a cabinet
full of documents has no impact on other documents.
·
Computers generally reduces the
errors of processing. However if there is an error in input data, it can result
in major blunders in the processing which the computer system is unable to
detect. In manual systems the chances of such blunders passing undetected and
corrected in much less.
CLASSIFICATION OF
COMPUTERS
Computers can be
generally classified by size and power as follows, though there is considerable
overlap:
1. Digital
Computers
2.
Analog Computers
3.
Hybrid Computers
4.
Mainframe Computers
5.
Super Computers
1.
Personal
or Digital Computers: A small, single-user computer based
on a microprocessor. In addition to the microprocessor, a personal computer has
a keyboard for entering data, a monitor for displaying information and a
storage device for saving data.
Personal computers
first appeared in the late 1970s. out of the first and most popular personal
computers was the Apple II, introduced in 1977 by Apple Computer. During the
late 1970s and early 1980s, new models and competing operating systems seemed
to appear daily. Then, in 1981, IBM entered the fray with its first personal
computer, known as the IBM PC. The IBM PC quickly became the personal computer
of choice and most other personal computer manufacturers fell by the wayside.
One of the few companies to survive IBM’s onslaught was Apple Computer, which
remains a major player in the personal computer marketplace.
Personal computers/Digital
Computers broadly divided in following types:
i.
Digital
Computers:
Digital Computer is capable of
receiving information in a particular form and performing sequence of
operations in accordance with a predetermined but variable set of procedural
instructions to produce a result in the form of information or signal that
means digits 0 to 1.
ii.
Desktop
Computers:
Many people use desktop
computers at work, home, school or the library. They can be small, medium or
large in style and usually sit on a desk. Once you add a monitor, mouse and a
keyboard you have what is typically known as a desktop computer.
Most desktop computers are easy
to upgrade and expand, or add new parts. Another benefit of desktop computers
is the cost. If you compare a desktop and a laptop with the same features, you will
most likely find that the desktop computer is priced lower.
iii.
Laptop
Computers:
The second type of computer
that you may be familiar with is a laptop computer, or laptops as they are
often referred to. Laptops are battery or AC-powered personal computers that
are more portable than desktop computers, allowing you to use them almost
anywhere.
Since laptop is smaller than a
desktop, it’s more difficult to access the internal components. That means you
may not be able o upgrade them as much as a desktop. However, it’s usually
possible to add more RAM or a bigger hard drive.
iv.
Tablet
Computers:
These use a touch-sensitive
screen for typing and navigation. Since they don’t require a keyboard or mouse,
tablet computers are even more portable than laptops. The iPad is an example of
a tablet computer.
v.
Mobile
Phones:
Many mobile phones can do a lot
of things a computer can do, such as browsing the internet or playing games.
These phones are often called smart phones.
vi.
Game
Consoles:
A game console is a
specialized kind of computer that is used for playing video games. Although
they are not as fully-featured as a desktop computer.
vii.
Workstation:
A powerful, single-user
computer. A workstation is like a personal computer, but it has a more powerful
microprocessor and a higher-quality monitor.
A type of computer used for
engineering applications (CDA/CAM), desktop publishing, software development
and other types of applications that require a moderate amount of computing
power and relatively high quality graphics capabilities.
Workstations generally come with a large, high-resolution graphics
screen, at least 64 MB of RAM,
built-in-network support and a graphical user interface. Most workstations also
have a mass storage device such as a disk drive, but a special type of
workstation, called a diskless workstations, comes without a disk drive. The
most common operating systems for workstations are UNIX and Windows NT.
viii.
Mini
Computer:
A multi-user computer capable
of supporting from 10 to hundreds of users simultaneously.
A midsized computer in size and
power, minicomputers lie between workstations and mainframes. In the past
decade, the distinction between large minicomputers and small mainframes has
blurred, however, as has be distinction between small minicomputers and
workstations. But in general, a minicomputer is a multiprocessing capable of
supporting from 4 to about 200 users simultaneously.
2. Analog Computers: Analog
Computers are mostly used for measuring frequently changing physical qualities
like temperatures, pressure, speed etc. These computers generally receive
analog data as their input from mechanical devices and calibrate the results.
Ex:
Temperature,
heat
Analog Computers are mostly used in
engineering and scientific fields.
3.
Hybrid
Computers: Hybrid Computers are combination of
analog and digital computers. They have the characteristics of both Computers.
These are useful where calculations are to be performed on analogous data and
results are to be reported in numerical or digital form.
The computers are mostly used in
hospitals and medical field.
Ex:
ECG
Machines, Blood Pressure measuring Instruments.
4.
Mainframe:
A
powerful multi-user computer capable of supporting many hundreds or thousands
of users simultaneously. A very large expensive computer capable of supporting
hundreds, or even thousands of users simultaneously. In the hierarchy that
starts with a simple microprocessor (in watches) at the bottom and moves to
supercomputers at the top, mainframes are just below supercomputers. In some
ways, mainframes are more powerful than supercomputers because they support
more simultaneously programs. But supercomputers can execute a single program
faster than a minute than a mainframe. The distinction between small mainframe
and minicomputers is vague, depending really on how the manufacturer wants to
market its machines.
5.
Supercomputer:
An
extremely fast computer that can perform hundreds of millions of instructions
per second. The fastest type of computer. Supercomputers are very expensive and
are employed for specialized applications that require immense amounts of
mathematical calculations. For example, whether forecasting requires a
supercomputer. Other uses of supercomputers include animated graphics, fluid
dynamic, calculations, nuclear energy research and petroleum exploration.
The chief difference
between a supercomputer and a mainframe is that a supercomputer channels all
its power into executing a few programs as fast as possible, whereas a mainframe
uses its power to execute many programs concurrently.
