Download What is a Computer?

Introduction to Computing
CS-301
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What Is Science?
What is Technology?
What is Computer?
History Of Computer
Generation of Computer
Types of Computer (By Function)
Types of Computer (By Size)
Applications Of Computer
Capabilities of Computer
Limitation of Computer
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Science is "knowledge attained through study
or practice"
Knowledge covers general truths of the
operation of general laws, esp. as obtained and
tested through scientific method [and]
concerned with the physical world."
Refers to a system of acquiring knowledge.
This
system
uses
observation
and
experimentation to describe and explain
natural phenomena.
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Practical application of science is technology.
Technology is a human innovation in action
that involves the generation of knowledge and
processes to develop systems that solve
problems.
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Information technology refers to both the
hardware and software that are used to store,
retrieve, and manipulate information.
The practice of creating and/or studying
computer systems and applications.
A Simple Definition
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an electronic machine that can store and work with large amounts of
information.
Complete Definition
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a programmable usually electronic device that can store, retrieve, and
process data.
2nd Definition
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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.
Finally we conclude that A Computer is:
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An electronic device that can perform the
following tasks:
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Respond predictably to input
Store the set of instructions needed to process
the input
Process the input according to these
instructions
Store the results of processing
Output information
How is a computer defined?
Electronic device operating under the control of
instructions stored in its own memory
Accepts data
Raw facts, figures,
and symbols
Processes data into
information
Data that is organized,
meaningful, and useful
Produces and stores results
How computer works???:
All computers take in information called input and
give out information called output
Calculating Machines
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The first calculating device called
ABACUS was developed by the
Egyptian and Chinese people.
Its only value is that it aids the
memory of the human performing the
calculation.
A skilled abacus operator can work
on addition and subtraction problems
at the speed of a person equipped
with a hand calculator
Abacus Computer
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Napier’s bones
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English mathematician John Napier built a
mechanical device for the purpose of
multiplication.
He invented logarithms, which are a technology
that allows multiplication to be performed via
addition.
The magic ingredient is the logarithm of each
operand, which was originally obtained from a
printed table.
Napier also invented an alternative to tables,
where the logarithm values were carved on ivory
sticks which are now called Napier's Bones.
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Slide Rule
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English mathematician Edmund Gunter developed the slide
rule. This machine could perform operations like addition,
subtraction, multiplication, and division. It was widely used
in Europe in 16th century.
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Pascal's Machine
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Pascal invented the Pascaline as an aid for his father
who was a tax collector. Pascal built 50 of this geardriven one-function calculator (it could only add).
A machine consisted of wheels, gears and cylinders,
that could add and subtract .
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Leibniz’s Multiplication and Dividing Machine
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It could both multiply and divide.
 German co-inventor managed to build a fourfunction (addition, subtraction, multiplication, and
division) calculator that he called the stepped reckon
 It employed fluted drums having ten flutes
arranged around their circumference in a stair-step
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fashion.
Babbage’s Analytical Engine
Charles Babbage (father of computer) built a
mechanical machine to do complex mathematical
calculations.
Mechanical and Electrical Calculator
Mechanical calculator was developed to perform
all sorts of mathematical calculations. Later
mechanical calculator was developed to the
electrical calculator.
Modern Electronic Calculator
 It can do all kinds of mathematical computations
and store some data permanently.
 Its size is too small.
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What do you mean by Generation of
Computer?????
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Generation in computer terminology is a change in
technology a computer is/was being used. Initially, the
generation term was used to distinguish between varying
hardware technologies.
The history of computer development is often referred to in
reference to the different generations of computing devices.
A generation refers to the state of improvement in the
product development process.
This term is also used in the different advancements of new
computer technology.
There are five generations of computer.
Each generation is characterized by major technological
development that fundamentally changed the way
computers operate, resulting in increasingly smaller,
cheaper, and more powerful and more efficient and reliable
devices.
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The period of first generation was 1946-1959.
The computers of first generation used vacuum
tubes as the basic components for memory and
circuitry for CPU (Central Processing Unit).
These tubes, like electric bulbs, produced a lot
of heat and were prone to frequent fusing of
the installations, therefore, were very
expensive and could be afforded only by very
large organizations.
In this generation mainly batch processing
operating system were used. Punched cards,
paper tape, and magnetic tape were used as
input and output devices.
The main features of first generation are:
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Vacuum tube technology
Unreliable
Supported machine language only
Very costly
Generated lot of heat
Slow input and output devices
Huge size
Need of A.C.
Non-portable
Consumed lot of electricity
Punched cards
Some computers of this generation were:
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ENIAC
EDVAC
UNIVAC
IBM-701
IBM-650
Vacuum
Tube
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The period of second generation was 1959-1965.
In this generation transistors were used that were cheaper,
consumed less power, more compact in size, more reliable and
faster than the first generation machines made of vacuum tubes.
In this generation, magnetic cores were used as primary memory
and magnetic tape and magnetic disks as secondary storage
devices.
In this generation assembly language and high-level
programming languages like FORTRAN, COBOL were used.
The computers used batch processing and multiprogramming
operating system.
The main features of second generation are:
 Use of transistors
 Reliable in comparison to first generation computers
 Smaller size as compared to first generation computers
 Generated less heat as compared to first generation
computers
 Consumed less electricity as compared to first
generation computers
 Faster than first generation computers
 Still very costly
 A.C. needed
 Supported machine and assembly languages
Some computers of this generation were:
 IBM 1620
IBM 7094
UNIVAC 1108
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The period of third generation was 1965-1971.
The computers of third generation used integrated
circuits (IC's) in place of transistors.
A single IC has many transistors, resistors and
capacitors along with the associated circuitry. The
IC was invented by Jack Kilby.
This development made computers smaller in size,
reliable and efficient. In this generation remote
processing, time-sharing, multi-programming
operating system were used.
High-level languages (FORTRAN-II TO IV,
COBOL, PASCAL PL/1, BASIC, ALGOL-68 etc.)
were used during this generation.
The main features of third generation are:
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IC used
More reliable in comparison to previous two generations
Smaller size
Generated less heat
IC (Integrated
Faster
Circuit)
Lesser maintenance
Still costly
A.C needed
Consumed lesser electricity
Supported high-level language
Some computers of this generation were:
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IBM-360 series
Honeywell-6000 series
PDP(Personal Data Processor) IBM-370/168
TDC-316
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The period of fourth generation was 1971-1980.
The computers of fourth generation used Very Large
Scale Integrated (VLSI) circuits.
VLSI circuits having about 5000 transistors and other
circuit elements and their associated circuits on a single
chip made it possible to have microcomputers of fourth
generation.
Fourth generation computers became more powerful,
compact, reliable, and affordable. As a result, it gave
rise to personal computer (PC) revolution.
In this generation time sharing, real time, networks,
distributed operating system were used.
All the high-level languages like C, C++, DBASE etc.,
were used in this generation.
The main features of fourth generation are:
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VLSI technology used
Very cheap
Portable and reliable
Use of PC's
Very small size
Pipeline processing
ICs with VLSI
No A.C. needed
(Very Large Scale
Integration)
Concept of internet was introduced
Great developments in the fields of networks
Computers became easily available
Some computers of this generation were:
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DEC 10
STAR 1000
CRAY-1(Super Computer)
CRAY-X-MP(Super Computer)
PDP 11
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The period of fifth generation is 1980-till date.
In the fifth generation, the VLSI technology became
ULSI (Ultra Large Scale Integration) technology,
resulting in the production of microprocessor chips
having ten million electronic components.
This generation is based on parallel processing
hardware and AI (Artificial Intelligence) software.
AI is an emerging branch in computer science,
which interprets means and method of making
computers think like human beings.
All the high-level languages like C and C++, Java,
.Net etc., are used in this generation.
AI includes:
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Robotics
Neural Networks
Game Playing
Development of expert systems to make
decisions in real life situations.
Natural language understanding and
generation.
The main features of fifth generation are:
 ULSI technology
 Development of true artificial intelligence
 Development of Natural language processing
 Advancement in Parallel Processing
 Advancement in Superconductor technology
 More user friendly interfaces with multimedia features
 Availability of very powerful and compact computers
at cheaper rates
Some computer types of this generation are:
 Desktop
Laptop
NoteBook
 UltraBook
ChromeBook
Computers Can be divided into the following
types on the basis of their working
(Functionality):
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2.
3.
Analog Computers
Digital Computers
Hybrid Computers
Analog Computers:
 An analog Computer does not operate with
digital signals.
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recognizes data as a continuous
measurement of a physical property.
 It has no state. Analog computer is difficult to
operate and use.
 Voltage ,pressure, speed and temperature are
some physical properties that can be
measured in this way.
 Analog computer is mainly used in the field
of engineering and medicine.
Examples:
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The speed of the car is measured by
speedometer
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Analog clock measures time by the distance
of the hands of a clock around a dial.
Digital Computers:
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A Digital Computer Works with Digits.
Everything Is described in two states i.e.
either on or off.
The number 1 represents on and 0 represents
off state. it operates by counting numbers or
digits and gives output in digital form.
The digital computers are very fast. These
computers store result in digital form.
Digital Computer
Examples:
1. Digital watch is a good example of digital
computer.
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Score board that directly count discrete values
such as the time left to play and the score of
each team.
Hybrid Computers:
These types of computers are, as the name
suggests, a combination of both Analog and
Digital computers.
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hybrid computer combines the best
characteristics of both the analog and digital
computer.
 It can accept data in analog and digital form.
Examples:
 Hybrid
computer devices may calculate
patient’s heart function ,temperature, blood
pressure etc.
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According to size there are four main types of
computer.
Super Computer
Mini computer
Main frame
Micro Computer
Super Computer:
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Supercomputers are one of the fastest computers
currently available.
Supercomputers are very expensive and are
employed for specialized applications that require
immense amount of mathematical calculations
(number crunching).
For example, weather forecasting, scientific
simulations, (animated) graphics, fluid dynamic
calculations, nuclear energy research, electronic
design, and analysis of geological data (e.g. in
petrochemical prospecting).
Mainframe:
 Mainframe is very large in size and is
an expensive computer capable of
supporting hundreds or even
thousands of users simultaneously.
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Mainframe executes many programs
concurrently and supports many
simultaneous execution of programs
Mini Computer
It is a multi-user computer
system which is capable of
supporting hundreds of users
simultaneously.
It is a midsize multiprocessing system capable of
supporting up to 250 users
simultaneously.
Micro Computer:
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Personal Computer
Work Station
Personal Computer
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It is a single user computer system having moderately
powerful microprocessor.
A PC can be defined as a small, relatively inexpensive
computer designed for an individual user.
PCs are based on the microprocessor technology that
enables manufacturers to put an entire CPU on one
chip.
Businesses use personal computers for word
processing, accounting, desktop publishing, and for
running spreadsheet and database management
applications.
At home, the most popular use for personal computers
is playing games and surfing Internet.
Work Station
 It is also a single user computer system which is similar to
personal
computer
but
have
more
powerful
microprocessor.
 Workstation
is a computer used for engineering
applications, desktop publishing, software development,
and other such types of applications which require a
moderate amount of computing power and relatively high
quality graphics capabilities.
 Workstations generally come with a large, high-resolution
graphics screen, large amount of RAM, inbuilt 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 workstation, comes without a disk drive.
Business
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A computer has high speed of calculation,
diligence, accuracy, reliability, or versatility
which made it an integrated part in all business
organizations.
Computer is used in business organizations for:
Payroll calculations
Budgeting
Sales analysis
Financial forecasting
Managing employees database
Maintenance of stocks etc.
Banking
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Today banking is almost totally
dependent on computer.
Banks provide following facilities:
Banks provide online accounting facility,
which includes current balances, deposits,
overdrafts, interest charges, shares, and
trustee records.
ATM machines are making it even easier
for customers to deal with banks.
Insurance
 Insurance companies are keeping all records up-todate with the help of computers. The insurance
companies, finance houses and stock broking firms are
widely using computers for their concerns.
 Insurance companies are maintaining a database of all
clients with information showing
 procedure to continue with policies
 starting date of the policies
 next due installment of a policy
 maturity date
 interests due
 survival benefits
 bonus
Education
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The computer has provided a lot of facilities in the
education system.
The computer provides a tool in the education system
known as CBE (Computer Based Education).
CBE involves control, delivery, and evaluation of
learning.
The computer education is rapidly increasing the
graph of number of computer students.
There are number of methods in which educational
institutions can use computer to educate the students.
It is used to prepare a database about performance of
a student and analysis is carried out on this basis.
Marketing
 In marketing, uses of computer are following:
 Advertising - With computers, advertising
professionals create art and graphics, write and
revise copy, and print and disseminate ads with
the goal of selling more products.
 At Home Shopping - Home shopping has been
made possible through use of computerized
catalogues that provide access to product
information and permit direct entry of orders to
be filled by the customers.
Health Care(Medical)
Computers have become important part in hospitals, labs, and
dispensaries.
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The computers are being used in hospitals to keep the record of patients
and medicines.
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It is also used in scanning and diagnosing different diseases.
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ECG, EEG, Ultrasounds and CT Scans etc., are also done by
computerized machines.
Some major fields of health care in which computers are used are:
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Diagnostic System - Computers are used to collect data and identify
cause of illness.
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Lab-diagnostic System - All tests can be done and reports are prepared
by computer.
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Patient Monitoring System - These are used to check patient's signs for
abnormality such as in Cardiac Arrest, ECG etc.
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Pharma Information System - Computer checks Drug-Labels, Expiry
dates, harmful drug’s side effects etc.
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Surgery : Nowadays, computers are also used in performing surgery.
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Engineering Design
 Computers are widely used in Engineering purpose.
 One of major areas is CAD (Computer aided design).
That provides creation and modification of images.
Some fields are:
 Structural Engineering - Requires stress and strain
analysis for design of Ships, Buildings, Budgets,
Airplanes etc.
 Industrial Engineering - Computers deal with design,
implementation and improvement of integrated
systems of people, materials and equipments.
 Architectural
Engineering - Computers help in
planning towns, designing buildings, determining a
range of buildings on a site using both 2D and 3D
drawings.
Military
 Computers are largely used in defense.
 Modern tanks, missiles, weapons etc. Military also
employs computerized control systems.
 Some military areas where a computer has been
used are:
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Missile Control
Military Communication
Military Operation and Planning
Smart Weapons
Communication
 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 for. Some main areas in this
category are:
E-mail
 Chatting
 Usenet
 FTP
 Telnet
 Video-conferencing
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Government
Computers play an important role in government.
Some major fields in this category are:
 Budgets
 Sales tax department
 Income tax department
 Male/Female ratio
 Computerization of voters lists
 Computerization of driving licensing system
 Computerization of PAN card
 Weather forecasting
Computers have some significant characteristics
because of which they are becoming versatile
day by day. They have several capabilities and
some limitations.
Following are some important capabilities/
characteristics of Computers :
Speed
Processing
Recalling
Consistency
Versatility
Storage Capacity
Accuracy
Control sequence
Communication
Cost Reduction
Speed:
Computers can carry out instructions in less than a millionth of a second.
For instant , a small computer can sort a set of hundred names in less than
a hundredth of a second.
Storage Capacity:
Computers have the capacity to store large amounts of instructions and
data and supply stored information to us when we ask for it. This is an
advantage over our brains where it is difficult to store all information we
acquire for long time
Processing
A computer can process the given instructions. It can perform different
types of processing like addition, subtraction, multiplication and division.
It can also perform logical Functions like comparing two numbers to
decide which one is greater.
Accuracy
Accuracy means to provide result without any error. Computer can
process large amount of data and generate error free results.
Recalling
A computer can recall the stored data and information as
and when required . The data stored in the computer can be
used at a later time. The computer can recall the data within
few seconds .
Control Sequence
A computer works strictly according to the given
instructions. It follows the same sequence of instructions
that is given to a Program.
Consistency
Computers works in consistent way. It does not lose
concentration due to heavy work. It does not become tired
or bore .Computer performs all the jobs with equal
attention.
Communication
Most computers have the capability to communicate with other
computers. We can
connect two or more computers by
Communicating device such as modem. These computers can
share data , instructions and information.
Versatile
A computer can perform different types of tasks. We can use
computers in hospitals , banks or at home. A variety of facilities
are available through computers.
Cost Reduction
By using computers we can perform a difficult task in less time
and less cost. For example we may have to hire many persons to
handled an office. The same work can be performed by a single
person with the help of computer. It reduce the cost.
We have understood the importance of computer in our lives.
Does that means that a computer act like an Obedient
assistant who can perform all tasks repeatedly at high speed
without any error?
Lack of Commonsense
Yes to some extent computer acts as human being. But there is big
difference between the machine and master. A computer is only a tool. It
cannot think. It does not have Intelligence or commonsense as well.
Inability to correct
When we instruction to the computer we must give the
correct instructions . A computer cannot correct the wrong
instruction itself. This follows the fact that computer cannot
use its brain because it does not have one!
Dependence on human instructions
A computer cannot generate any information on its own.
It can only do what it is told to do.