BCA - FCIT - Sem I

1BCA1

Fundamentals of Computers
& Information Technology

1BCA1, Fundamentals of Computers & Information Technology

Edition: July 2013
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TABLE OF CONTENTS

Chapter 1 : Know the Computer ---------------------------------------------------5-30
Chapter 2 : Personal Computer-------------------------------------------------- 31-44
Chapter 3 : Boolean Algebra and Logic Gates --------------------------------- 45-62
Chapter 4 : Number System ----------------------------------------------------- 63-78
Chapter 5 : Data Representation and Binary Arithmetic---------------------- 79-92
Chapter 6 : Input Devices ------------------------------------------------------- 93-108
Chapter 7 : Output Devices ---------------------------------------------------- 109-130
Chapter 8 : Central Processing Unit ------------------------------------------- 131-136
Chapter 9 : Storage Devices --------------------------------------------------- 137-168
Chapter 10 : Basics of Software ------------------------------------------------ 169-184
Chapter 11 : Operating System ------------------------------------------------- 185-202
Chapter 12 : Disk Operating System ------------------------------------------- 203-232
Chapter 13 : Programming Languages ----------------------------------------- 233-248
Chapter 14 : Virus ---------------------------------------------------------------- 249-260
Chapter 15 : Communication and IT -------------------------------------------- 261-274
Chapter 16 : Networks ----------------------------------------------------------- 275-294
Chapter 17 : Internet ------------------------------------------------------------ 295-308
Chapter 18 : Management Information System ------------------------------- 309-322
Chapter 19 : Applications of Computers and Information Technology ------ 323-340



1 Know the Computer Know the Computer
NOTES
The Chapter Covers :
n Introduction
n What does computer stand for?
n Strengths of computers
n Limitations of computers
n Fundamental uses of computers
n Development of computers
n Types of Computers
n Generations of Computers
n Summary
n Exercise

Introduction 5

______________________________________________________________________________________

Suppose you are a student or a teacher or a professional concerned with any trade and
you are asked what computer is. Can you afford ‘No’? It is quite amazing that somebody
is literate and does not know what computer is. Seems unbelievable? Today, computer is
everywhere and anybody on the earth can hardly ignore the truth of its existence. You go
to a departmental store there you will find a bar code reader that checks bar code on your
products purchased and a printer that prints your bill having connected to a computer. The
maching loking like an has changed the way of our complete style of living. Post cards have
been replaced with emails. Banking has got new dimensions. Ticketing has taken a new
shape. All look like as if some hidden power is commanding like a Sanskrit word Tatha-
Astu that means-‘Be as you wish’. When this machine has changed the way of our life
, should not this be our responsibility to know every bit and byte of this divine creation?
I personally do not call it human creation, rather it is a divine creation whose idea was
thrust upon human minds to make our lives comfortable. This chapter is an effort to deliver
you maximum information on what this is.

Fundamentals of What does computer stand for?
Computers &
Information Technology ______________________________________________________________________________________

NOTES Simply defining, a computer is an electronic machine that performs arithmetic and
logical operations. In other words, computer can be defined as a machine that can be
6 used for manipulating data according to a list of instructions. However, computer is
not limited today to a few works as it was in its infancy. Early electronic computers were
of the size of a large room, consuming as much power as several hundred modern personal
computers. Today, computers take numerous physical forms. Computers can be made
small enough to fit into a wrist watch and be powered from a watch battery. We can find
around us personal computers and their portable equivalents as well. There are embedded
computers in vogue also. Embedded computers are small, simple devices that are often
used to control other devices—for example, they may be found in machines ranging from
fighter aircrafts to industrial robots, digital cameras, and even children’s toys.

The ability to store and execute programs makes computers extremely versatile and dis-
tinguishes them from calculators. Any computer with a certain minimum capability is, in
principle, capable of performing the same tasks that any other computer can perform.
Therefore, computers with capability and complexity ranging from that of a personal digital
assistant to a super computer are all able to perform the same computational tasks as long
as time and storage capacity are not considerations.

Why computer literacy ?

______________________________________________________________________________________

Why is it necessary to know about computers ? Is it just an effort to establish an industry
or has it really become so important that one can't do without knowing about it ? Before
finding an answer to it, please have a glance at the application of computers around you.
You must be watching T.V. everyday. Is it possible to telecast news or other programs
without being aided by computer ? Not at all. In Television studio, one uses computerised
graphics and high level computer operated light system. In addition, in live telecast of the
news and so many other activities, the application of computer is a must. Have you ever
paid attention to weather news? How are you given weather forecast? The meterological
department, besides using an extensive computer network for it, uses satellite linked
computer forecast system. Have you ever paid attention to the utility of computer in a car
or bike ? The fuel system of a bike or car is controlled by a computer itself. Have you
ever glanced at then Traffic control system ? The entire traffic-light system is controlled by
a computer. In developed countries the entire traffic is controlled by a computer. You must
be aware of the utility of computer in the banking system, which is completely based on
computer. The automated taylor machine in itself is a complete computer. Can you think
of an area where computer is not in use ? Computer helps us in air-craft landing, medicinal
treatment, telecom, education, maintaining the relationship, managing the finance, doing
research, entertainment, and in many such things.

Now, you should tell whether computers literacy is a must for you ? And I think, there
is hardly a single wise person who will reply in negation. Today computers literacy is as
essential as is reading or writing. It is the most important factor in getting a job. If you
are in business, it is as necessary as knowing the details and secrets of a business. Today
it is the foundation of information system and information leads to success. The more
updated you are the faster you lead towards success. Computer today, plays an important
role in decision-making. If you are a business manager and want to take an important
decision, you have at your disposal, not only one intelligent mind, but a collection of
the best brains in the world with the help of computer. This is called Experts System.
In management, computer has generated a Management Information System which is a
must to know for the managers.

Today, every body from a studen a farmer, a doctor, a merchant, an expert, a writer, a
scientist, all are incomplete without computer literacy. Computer awareness is more im-
portant to a person than his personal reasons. I read, a true story in an edition of Readers'
Digest a few years ago. In which, a child was suffering from untreatable disease, but the

child's mother didn't lose heart and conducted a reserch on that disease on the internet Know the Computer
and on the basis of that research, got a medicine with a mixture prepared by some NOTES
company and saved her child. It was only because of computer literacy that the mother
could save her child. 7

Strengths of computers

______________________________________________________________________________________

Now a days, it is very easy to mention and enlist the strengths of a computers. Even a
common man can do it. Let us know what strengths a computer has.

Now-a-days, computer is being used in almost every field, because of its strengths which
are as follows :

n Speed : In case we wish to go somewhere we can walk down to our destination,
but we generally opt for some mode of conveyance, so that we can reach the
destination earlier and faster. We use machine to speed up our work and to save time
and be comfortable. Similarly, computer is a machine which can carry out millions of
mathematical calculations in few seconds.

For instance, if we want to multiply 440 × 56, we would take 1 to 2 minutes to solve.
If we use calculator to solve the above problem, it may take 5 seconds, but a modern
computer programmed for such calculations can carry out 8 millions of such calculations
simultaneously at the same period of time.

n Automation : In our daily life, we may find lots of automatic machines around us
whether, microwave oven, tape recorder, TV, washing machine which save our time
and energy and perform their respective jobs almost automatically. But, when we talk
in context of computer, automation gives a different meaning. Calculations are also
done by calculators automatically, but at each step users have to feed numbers and
have to press the concerned button. Thus job becomes a bit manual though the
calculations are automatic.

As far as automation feature in computer is concerned, here automation is cent
percent. Once a computer is programmed to perform a special task, it keeps on doing
the same without any interruption. For example, a data entry operator enters data in
a program and gets reports based on data without preparing them time and again.

n Accuracy : Computers are accurate. They do not make mistakes in calculations.
In case, we want to calculate the multiplication of two 10 digit numbers, we may
take a lot of time and there could be several chances of mistakes and miscalculations.
But computers easily carry out any kind of operation whether arithmetic or logical.
We can meet a lot of persons complaining about mistakes made by computers, but
it is human error committed by either the person who entered the data or who
programmed it so.

n High Storage capacity : Computer has a large storage capacity. Computer can
store around millions and billions of words. Besides storing any kind of data
whether picture, text, or sound it can retain them for a long time (period can
be in years even) and can be retrieved with the same condition as stored, any
moment within few seconds.

n Versatility : Computers are very versatile. They have spread across the globe just
because of this feature. They can do variety of jobs depending on the instructions fed
to them and their hardware characteristics. Modern computers are capable of handling
not only complex arithmetical problems, but also lots of jobs unrelated to numbers,
like railways and airline ticket reservations. Now, computer is not the name of any kind
of single machine, but it covers a group of machines. It has influenced commercial
world to a great extent. Computers can be attached with several kinds of peripheral
devices to accomplish variety of jobs.

A printer can be attached with computer to generate reports and documents. For

Fundamentals of graphical printing, some special larger printers or plotters can be attached with it. With
Computers & the help of a special device called "modem", which when attached with computer,
Information Technology we can browse Internet, can send e-mail, voice or pictures.

NOTES Computer is a good entertainer too, we can play video games, can listen to melodious
songs, watch movies and even solve riddles on it.
8
n Diligence : Diligence means being constant, careful and steady in making efforts.
Human beings after working for several hours, get tired and continuously working for
several days may lead him to suffering from fever and weakness. They may become
sad, depressed, bored which cause lack of concentration to wards their work. They
cannot do the same work repeatedly with the same quality. But, computer does not
have any sort of weakness, tiredness, isolation and boredom doing the same task,
again and again. It keeps on doing the work provided by its master, i.e. the user,
irrespective of any feeling of monotony, isolation, interest and joy.

n Reliability : As mentioned earlier, accurate storing, automation, retrieval of data
without any change, diligence and high speed make computers very reliable. People
from all professions and intellects rely on it blindly.

Limitations of computers

______________________________________________________________________________________

Jotting down the limitations of computers is a challenging task, but if we think properly
we can throw light on the following limitations of computers. Let's see them one by one.

Computer has undoubtedly contributed in an unprecedented way to make human lives
tremendously relaxed. Invention of computer has got great imprints on all the tools and
devices produced so far. The last section delivered a broad discourse on the strengths of
computers.

The strengths of computers are actually the main reasons of its popularity today. However,
like any man-made machine, computer has got some limitations. Without limitations, the
making of any equipment can not be imagined. Therefore, it is necessary to discuss the
limitations with the strengths of computers. The limitations of computers are as follows-

n Lack of Intelligence – Computer is a machine. Its duty is to perform users’ instruc-
tions diligently. Computer, in no case executes instructions more or less than as
instructed. Although, computer scientists are thinking of generating artificial intelli-
gence and expert system in computers, limitations will be minimized to a great extent
if succeeded, despite natural intelligence will remain a mystery and machine intelli-
gence can never outpower human intelligence.

n Lack of Common Sense – Computer works just like a foolish servant. Suppose you
ask it to go and buy vegetables. It will comply with your command. It will go to the
market, buy vegetables but will never return back. Ask why? Candid answer is that
you have certainly asked it to go and buy vegetables but you had not asked it to come
back. It shows that computer badly lacks common sense.

n Unable in Self Protection – No matter how powerful computer is but the truth is
that the user holds its control and it is controled in the way the user controls it.
Computer can not protect itself in any way. For example, a person namely Sameer
creates an email account and assigns a specific password to open his account. Com-
puter now sees only the password being entered while accessing the mail account and
it does not matter if the person who is accessing the account is Sameer or not.
Likewise, you go to ATM (Automatic Teller Machine) and do transaction with the bank
by inserting card and PIN (Personal Identification Number). That is all for that ATM.
It never asks if you are the genuine master of the ATM card. This outlook of the
computer makes it very reliable while on the other hand puts a question mark whether
the computer is as reliable as it is assumed.

Development of computers Know the Computer
NOTES
______________________________________________________________________________________
Check Your Progress :
The Abacus 1. What is Computer ?
2. What are the strengths of
The history of computers dates back to 500 BC, when Figure 1.1 : Abacus
a calculating machine called Abacus was invented in computers ?
china. Abacus, a device of counting beads in strings or 3. Whate are the limitation of
rods, was used to calculate and store the immediate
results of mental arithmetic. Although the Abacus is still computers ?
widely used in countries like China, Japan and other
Asian countries, it does not provide long term storage
of information. This machine is capable of carrying out
addition, subtraction, multiplication and division.

The Abacus is the first real precursor of the adding machines and computers. It works
with the help of beads strung on wires and uses the principle of place value notation.

John Napier and the Napier's Bones

The pioneer device, Abacus satisfied most calculating requirements until the development
of western societies which required assistance in managing the large volume of
calculations needed to keep track of complex commercial and economic transactions.
The first such aid was the introduction of Logarithms unveiled by Edinburgh-born
mathematician John Napier. His work on Logarithms was produced in Great Britain
in 1614 named 'Mirifici logarithmorum canonis descripto'. Napier besides introducing
logarithmic table is also known for his Napier's Bones being used in multiplication.
The napier's bones adopted the same method of Abacus having only difference that
Abacus used notation to indicate fractional position while Napier's had the decimal
point.

In 1620, William Oughtred developed the "Slide Rule" based on the concept of
Logarithms. Both the above inventions viz., logarithm and slide rule were widely used
until the development of small electronic calculator in late 1960s.

Blaise Pascal and the Pascaline

Two further significant developments took place in the seventeenth century. The first
was the production of a mechanical calculator Pascaline by Blaise Pascal in 1642.
Pascaline was a mechanical machine having many toothed-wheels which worked on
the same principle on which a mechanical clock, odometer works. Each of the tooth-
wheel was having its positional value eg. ones, tens , hundreds etc. and having
numbers from 1 to 9 printed on it. Each of the wheel moves one point when the
preceding number-wheel completes its one rotation. This was the first mechanical
calculating machine and was capable of addition and subtraction. Speedometers of the
automobile work on the same principle of Pascaline. The second was more effective
produced by Gottfried Wilhelm Von-Leibnitz in 1694 which can also perform
multiplication and division. This machine was known as Reckoning machine or Leibnitz
wheel. This calculator was succeeded by a mechanical calculator, the Arithmometer
devised by Thomas de Colmar in 1820.

Figure 1.2 : Pascaline

9

Fundamentals of Jacquard's Loom
Computers &
Information Technology Meanwhile in 1801, a French weaver named Joseph
Jacquard invented such a weawing machine which
NOTES supplied design or pattern in clothes itself. If had a stiff
card with a series of holes punched on it. The card
blocked certain threads from entering the loom and let Figure 1.3 : Jacquard's
other threads go on to complete the weave. Though Loom
they had nothing to do with the history of computer,
the idea devised by Jacquard inspired Charles Babbage.
This loom of Jacquard provides two theoneo. First, the
information can be coded on Punch Card and the other
is the information loaded on the punchcard is a set of
instructions which will work as a program. Babbage
realized that the punched card system could also be
used to control the order of calculations in the analytical
engine, and he incorporated the device in his machine.

Charles Babbage's Difference Engine

Early 19th century is considered as the golden era in the history of computers. An
English professor from Cambridge University Charles Babbage took initiative to develop
a calculating machine for advanced mathematical calculations, which were previously
done manually using 'Handset mathematical tables'. These calculations could be
inaccurate if there were some errors in the table. To overcome this, Charles Babbage
developed a machine in 1822 called "Difference Engine".

This was purely a mechanical machine consisting of gears and shafts and driven by
steam. All expenses to develop Difference Engine were incurred by Govt. of Britain.
Charles Babbage's Difference Engine is the first computer to be thought of. The
Difference Engine was able to compute the values of a polynomial expression to six
decimal digits. It was a special purpose computing machine.

Figure 1.4 : Difference Engine Figure 1.5 : Analytical Engine

In 1833, he thought of building a general purpose computing machine and more advanced
than the Difference Engine, the new machine was "Analytical Engine". It was also a
steam-driven calculator able to perform 60 decimals each, and to handle any type of
calculations and other mathematical problems. The input to this machine was based on
punch cards. This machine was able to accept instructions through punch cards and store
them to produce outputs automatically. Charles Babbage paved the way for modern digital
computers, as his Analytical Engine was built around the same five components i.e.,

n Input
n Control
n Store
n ALU; and
n Output

10 which are used in modern digital computers. Hence, he

is known as the "Father of Modern Computer Science." Charles Babbage

Ada Augusta Know the Computer
NOTES
Charles Babbage's analytical engine was initially supposed
useless and therefore Babbage was very disappointed but Ada Augusta
unexpectedly Lady Ada Augusta, the daughter of famous Byron
English poet Lord Byron joined Babbage and helped him
develop instructions for doing computations on his analytical
engine. She was also the Countess of Lovelace hence
remembered as Lady Lovelace. If Charles Babbage was
honoured as the 'Father of Computer', Lady lovelace was the
first programmer in the world. To honour her, a programming
language "ADA" is named after her.

Hollerith Census Tabulator

In 1890, in the history of computer, the United States Census is an important event.
Before 1890 the census was carried out in a traditional way. The cansus which had
started in 1880 had taken 7 years to complete. To finish it in relatively shorter
period Herman Hollerith (1869-1926) invented a machine in which the punch
cards were run by electricity. The machine helped complete the census task within
3 years. In 1896, Hollerith set up a company, Tabulating Machine Company to make
punch-cards. In 1911 this company merged with another company and its name
changed to Computer Tabulating Recording Company.

In 1924, the name of this company again changed into International Business
Machine, which is, today, one of the leading companies in the world. Now the
computers entered into electro-mechanical era, for Hollerith's machine was
mechanical and was run on electricity.

Herman Hollerith

Figure 1.6 : Herman Hollerith tabulating machine

Dr. Howard Aiken and Mark - I

During 1940s, the electro-mechanical computing was Dr. Howard Aiken
dominating the scenario. In year 1944, Dr Howard Aiken
and four other engineers of IBM ventured together to
develop a machine, officially known as "Automatic
Sequence Controlled Calculator". It was sent to Harword
University in February of 1944 and was received there on
7 August 1944. There it was named Mark-I. This was
world's first electro-mechanical computer. It consisted of
wire networks equivalent to 500 miles and around 30
lacs of electric connections or relay inside. It was capable
of carrying out one multiplication in 6 seconds and a
division in 12 seconds.

In the mid of fourth decade of the 19th century the electronic concepts were fast 11
spreading and influencing computers also. Aiken and IBM-Mark-I became obsolete due
to electronic technology. In this technology, only signals produced by electric current
processed the requirement and no movable parts were required in the devices, based
on this technology. Hence it proved faster.

Fundamentals of
Computers &
Information Technology

NOTES

Figure 1.7 : Automatic Sequence Controlled Calculator or Mark-I

Atanosoff Berry Computer
In 1945, John Vincent Atanosoff and Clifford Berry developed an electronic machine
which was named ABC - Atanosoff-Berry Computer. This was the first digital electronic
computer.
Digital concept was also there when machines were mechanical or electro-mechanical.
In 1935, Konard Zuse of Germany made first digital computer using Binary Arithmetic
and program control. The name of computer was Z1; this was a mechanical machine,
later he developed a machine Z2 using electro-magnetic relays.
During 1945-46, John William Mauchly and JP Eckert developed first large general
purpose computer at the University of Pennsylvania, the ENIAC- the Electronic Numeric
Integrator And Computer.
We have witnessed termendous changes in computers and Information Technology,
However, in coming days, it may be that what we are using today becomes a part
of evolution of computers tomorrow.

John V Atanosoff

Figure 1.8 : Atanasoff Berry Computer or ABC

Generations of Computers

______________________________________________________________________________________

The generation of computer in itself is a subject of discussion. Let's know about the
different generations of computer and their period, main inventions and characteristics are.

In 1946, the first electronic device, vacuum tube based ENIAC computer initiated the
evolution of computer era. This evolution of computer era has witnessed a lot of
developments. We classify this evolution into five generations on the basis of main changes
occurred. They are as follows-

n First Generation – 1946 - 1956

n Second Generation – 1956 - 1964

n Third Generation – 1964 - 1971

12 n Fourth Generation – 1971 - Present

n Fifth Generation – Present and Future

First Generation of Computers (1946-1956) Know the Computer
NOTES
ENIAC

During the Second World War, American Figure 1.9 : The ENIAC
military had faced a lot of problems due to
technical complexity of targetting the enemy,
as this involved complex and tough
computation. Then Dr. John Mauchly, a
professor of the Moore School of Electrical
Engineering at the University of Pennsylvania
and his assistant J. Presper Eckert proposed an
electronic computer to overcome this. During
1943-1946, John William Mauchly and J. P.
Eckert developed the first large general purpose
computer at the University of Pennsylvania,
the ENIAC - the 'Electronic Numerical Integrator
And Calculator'. It was 100 feet long and 10
feet high. It consisted of 18000 vacuum tubes
and consumed 140 kilowatts of electricity. It
was 30 tonnes heavy.

John von Neumann and Concept of Stored Programs

There were a number of drawbacks to ENIAC including serious John von
cooling problems because of the heat generated by all the tubes Neumann
and, more importantly, ridiculously small storage capacity. Worst of
all, the system was quite inflexible. Each time a program was changed,
the machine had to be rewired. This last obstacle was overcome by
the Hungary-born mathematical genius Dr. John von Neumann.

W Mauchly J Presper
Eckert
Figure 1.10 : The UNIVAC- I

A holder of degrees in chemistry and physics, a great story-teller, and a man with total 13
recall, von Neumann was a member of the Institute for Advanced Study in Princeton,
New Jersey. One day in 1945, while waiting for a train in Aberdeen, Maryland, a member
of the ENIAC development team, Herman Goldstine, ran into von Neumann, who was
then involved in the top-secret work of designing atomic weapons. Since both persons
had security clearances, they were able to discuss each other's work, and von Neumann
began to realize that the difficulties he was having in the time-consuming checking of his
advanced equations could be solved by the high speeds of ENIAC. As a result of that
chance meeting, von Neumann joined the ENIAC team as a special consultant.

When the Army requested a more powerful computer than ENIAC, Von Neumann
responded by proposing the EDVAC ( for Electronic Discrete Variable Automatic
Computer), which would utilize the stored program concept. That is, instead of people
having to rewire the machine to go to a different program, the machine would, in less
than a second, "read" instructions from computer for switching to a new program. Von

Fundamentals of Neumann also proposed that the computer uses the binary numbering system , to take
Computers & the advantage of the two-state conditions of electronics ("on" and "off" to correspond
Information Technology to 1 and 0).

NOTES Mauchly and Eckert and others at the Moore School of Engineering set out to build
the EDVAC, but the first computer using the stored program concept was actually the
14 EDSAC, built in 1949 at Cambridge University in England. One reason that EDVAC was
delayed was that Eckert and Mauchly founded their own company in 1946 to build
what would ultimately be called the UNIVAC computer.

Attributes of the First Generation

n Vacuum Tubes : Vacuum tubes were the main logic elements
of the internal circuits of the first generation computers. Due
to the consumption of lot of electricity they also produced heat,
and this high rate of heat emission generally was the cause of
their getting unfunctional. Hence they required a special air-
conditioning unit to maintain an optimum functional temperature
and to keep these computers cool.

n Punch Card for Input/Output : In these computers, the punch Figure 1.11 : A
cards were used for inputting data and getting output. As these Vacuum tube
computers were based on punch cards, hence had low processing
speed.

n Magnetic Drum Internal Memory : First generation computers had magnetic drum
as primary internal storage. Data input through punch cards was stored on this
magnetic drum as magnetic signals.

n Limited Application : First generation computers were capable of carrying out few
commercial transactions i.e. payroll processing, billing and accounting. But at that
time these tasks by human personnels were comparatively cheaper as these computers
were very expensive.

n Programming in Machine and Assembly Language : A set of instructions which
regulates a computer to perform a specific task is called program. First generation
computers were programmed in Machine and Assembly languages.

Second Generation of Computers (1956-1964)

In the second generation of computers, vacuum Figure 1.12 : A Transistor
tubes were replaced with transistors. William
Schockley invented transistor in 1947 which
was used in second generation computers as
Vaccuam tube. The mechanism of transistor
was same as that of vacuum tube but it was
speedier, smaller in size and more reliable
than the tube. It consumed less energy and
emitted less heat.

Attributes of Second Generation

n Tape and Disk Secondary Storage : In these computers, magnetic tapes and disks
were also used for secondary data storage, besides punch cards

n Magnetic Core-Internal Memory: The magnetic drum in internal storage was
replaced by magnetic core, in the second generation of computers.

n Modular Hardware Elements : Maintenance of the first generation computer was
a tedious practice. Hence each of the computer units was given a modular design,
which led to easy maintenance and installation of computers.

n Programming in High Level Languages : To overcome the complexity in assembly
language and machine language, high level languages were developed e.g.,
FORTRAN (for Formula Translator) and COBOL (for Common Business Oriented
Language).

n Reletively Smaller and Less Energy Consuming. Know the Computer
NOTES
n Speeder and Alove Reliable
15
n Using Storage Device, Printer and Operating System.

During this phase of computer development, ANSI set new standards for high level
programming language. ANSI stands for American National Standards Institute.

n New Computer Applications : Second generation computers gave rise to :

n Air ticket Reservation System,

n Launch of Telestar and

n Evolution of Management Information System.

In 1962, IBM and American Airlines jointly developed the first Airlines Passenger Reservation
System. Telestar was a communication satellite launched in 1962. MIS helped executives
prepare reports with less paper work.

Third Generation of Computers (1964 - 1971)

The third generation of computers started in the mid of 1964 when IBM came forward
with the historical Computer Family; it was named as System 1360-line.

In 1958, at Texas Instruments, Jack Kilby completed the building of the first integrated
circuit, containing five components on a piece of germanium, half an inch long and thinner
than a toothpick. Among the computers of this generation. ICL2903, ICL1900, UNIVAC
1108 were notable.

Attributes of third generation

● Use of Integrated Circuit.

● Far smaller in size and lighter in
weight there the 1st and 2nd
Generation of computers.

● More Reliable.

● Portable and easy to maintain.

n Idea of Computer Family propagated Figure 1.13 : Univac-I
in this generation.

n All computer operations could be controlled by a specific Control Program called
operating system. Operating system itself is a group of many programs, each
program is responsible for controlling a single specific operation of the computer.

n Improvement in Software : During this generation more high level languages were
developed. Market was flooded with user-specific and requirement-specific programming
languages.

n Rise of Mini Computer : The size of computers was also minimized and named as
Mini Computer.

n First Mini Computer was PDP-8 which was as big as a refrigerator. It was made by
"Digital Equipment Corporation" and was worth $ 18000.

n Evolution of Word Processing : Preparation of documents using computer is called
Word Processing. It came into existence when IBM came forward with a machine-
MT/ST i.e., Magnetic tape selecting typewriter, in year 1964.

Fundamentals of Fourth Generation of Computers (1971-Present)
Computers &
Information Technology During this phase, Large Scale Integrated Circuits came into existence. These ICs were
having 300000 transistors in the area less than 1/4 of an inch. Finally, a whole CPU circuit
NOTES of a computer was designed in a small chip by Ted Hoff at Intel Corporation. This chip
was developed in 1970 and named Intel 4004, and given a technical name as Micro
Processor. Computers having microprocessor were called Micro Computers.

Now, a market-war started to make a computer useful for a common man in his daily life.
In the year 1970 only, MITS, a computer company launched the first micro computer- Altair
8800. MITS gave the contract of installing BASIC, a programming language on its micro
computer to a Harvard University student, Bill Gates. Bill Gates succeeded in that. Later,
he started his own company, Microsoft Corporation which is world’s no. 1 software company
today.

In year 1981, IBM entered the micro computing market, with its microcomputer - IBM-
Personal. Today Micro Computing Market is dominating the information technology market.

Bill Gates

Figure 1.14 : ALTAIR 8800 Micro Computer

Attributes of fourth Generation

n Microminiaturization : During this generation, the emphasis of developers was to
create the smallest circuits for computers. ICs made during this period grew smaller,
speedier and cheaper than before. Idea of VLSIC and LSIC was propounded during this
phase only. LSIC stands for Large Scale Integrated Circuit and VLSIC stands for Very
Large Scale Integrated Circuit. Today, as an outcome of the efforts even a fingernail-
sized silicon chip contains millions of circuits on it.

n Semiconductor Internal Memory : Fourth generation computers replaced the Magnetic
Core Internal Memory by Semi Conductor Internal Memory. This new memory was fast
in processing, small in size and low in cost.

n Further Improvements in Software : Computers became trendsetter during this phase.
Almost all commercial activities became computerised due to its speed and accuracy
feature. Consequently, several softwares were developed for different trades and
applications. Electronic spreadsheet, applications generator and databases were developed
during this phase. Working with Application softwares was easier than working with
languages of third generation.

n Design Support System : To make managers more comfortable with computer, DSS
was developed which can help them in day to day (routine) decision making activities.

W. thin the Buying capacity of a common man-

n More Efficient, Reliable and Speedier.

n Development of various networks of computers.
16

n Very Large Scale Integration.

Fifth Generation of Computers (Present and Future) Know the Computer
NOTES
Fifth generation of computers includes advanced computer technology of present time
and upcoming computers. Developers are striving hard to develop computer with 17
artificial intelligence. Today's computers are so advanced that they can even work almost
within every specialised area whether accounting, engineering, architecture, researches,
medicines etc.

In the beginning of this generation, computers were interconnected to share data and
information with each other. New ULSIC-Ultra Large Scale Integrated Circuits are replacing
VLSIC chips. The size of computers are also minimising day by day. We can see, watch-
sized computers are available in market today. Using portable computer and Internet, we
can exchange information, documents and even money beyond the boundaries.

Attributes of Fifth Generation

n Different sizes of computers : Size and structure of computers are being designed
as per requirement. We can find various models of desktop, laptop, palmtop in the
market today.

n Internet : It is a global network of computers. A great number of networks in the
world are mutually interconnected via Internet. New information related to health,
medicine, science, art, culture etc. can be available, on the single click of your mouse.

n Multimedia : The combination of sound, images, graphics and text called multimedia
is the gift from the fifth generation of computers.

n New Applications : Computer has so advanced, it can be used in almost every field
whether it is film-production, traffic-control, business, industry, research or anything.

Types of Computers

______________________________________________________________________________________

In the last section we have talked about the definition, evolution and generations of
computer. In this section we will discuss how many types of computer are there.

Since computer is a device to be used in various fields, there is a requirement that there
should be different computers for different areas. Computers which you use for your
personal tasks are different from the ones used in Scientific Research and Medical
Examinations. Some computers are for general purposes while a few one for specific
purposes. On the basis of their functions computers are divided into Micro, Workstation.
Mini, Mainframe and Super Computers.

Computer is a multipurpose machine and suited to almost all kinds of requirements. It
is very difficult to classify them straight forward, therefore we classify then on the following
bases :

n On the basis of applications.

n On the basis of purposes.

n On the basis of sizes.

Classification of Computers on the basis of Applications

On the basis of applications, computers can be classified as :

n Analog computer n Digital computer
n Hybrid computer

Showing figure analog way Showing the same figure digital way

Figure 1.15 : Comparison between analog and digital

Fundamentals of Analog Computers
Computers &
Information Technology These are the computers which can work with continuously variable physical parameters
e.g. pressure, temperature, length, voltage etc. and express them in numerals like a
NOTES thermometer does, which in fact does not calculate anything but compares body temperature
with relative expansion of mercury.
18
Analog computers are mainly being used in the field of science and engineering, as these
fields deal with the computation of physical quantities. But these computers only give
approximation in the values. For example, an analog computer in a patrol pump measures
the quantity of gasoline filled, calculates the related product value and shows it on the
display boards.

Digital computers

Digital computer works with digits. It uses numbers to stimulate real-time process. It
usually refers to general purpose programmable machine that can accomplish versatile task
as per the programs loaded into its memory. Digital computers are actually for business
purpose. These computers read and store data and programs in 0 and 1. Figure 1.15 shows
the comparison between analog and digital techniques.

Hybrid computers

These computers possess the property of both analog Figure 1.16 : Hybrid computer
and digital computers. Such computers are used in
medicine and surgery. The analog devices of computer
mainly compute temperature and blood pressure; and
the digital parts convert them in numeric value. Hence,
they jointly monitor the condition of the patient.

Classification of computers on the basis of purpose

On this basis only two classes have been made which are as under :

n General Purpose Computers

n Special Purpose Computers

General Purpose Computers

These are the computers which are capable of performing multiple tasks of various
nature. But these are general jobs such as word processor is used to prepare letters,
documents etc. These computers have a cheaper CPU. We can’t use these computers
for special purpose. The CPU of these computers have limited working capability.

Special Purpose Computers

These computers are made for special purposes. Their CPUs are specially designed for
a specific task. If that specific purpose requires different CPUs then that CPU is
designed in such a way that it alone can perform all functions, a good example of this
type of computer which is used in studios for music recording. This computer can
be attached to various musical instruments and other devices. It can also edit the
recorded music by inserting Special effects. Similarly in film industry, special purpose
computers are used for film editing. Besides these, the fields where special purpose
computers are used are as under:

n Space exploration
n Meteorology
n Defence (for missile navigation)
n In the field of physical & chemical research
n Traffic control
n Agriculture

n Satellite operations Know the Computer
n Medicine and surgery NOTES
n Oceanography
n Engineering 19

Classification on the basis of size

This classification has following categories:

n Micro Computers Figure 1.17 : Computers in Engineering
n Workstations
n Mini Computers
n Mainframe Computers
n Super Computers
n Embedded Computers

Actually this is a general classification, but sometimes its Figure 1.18 : Robot in
authenticity is suspicious as a large minicomputer could be Industries
bigger than Mainframe. A bigger computer is more efficient
in processing and has more additional devices. In computer,
larger the size is, more the price will be. The costs of a
computer system ranges from a few thousands to millions of
rupees.

Micro Computers

One great invention that took place in the year 1970, was the invention of microprocessors.
This led to the availability of cheaper computer system. This made possible to design, small
computers to the extent that they can be put on the desk or can be kept inside the
briefcase. They are smaller and can be installed either in home or in the office for personal
use. Hence they are called Personal Computers (PC).

Micro computers are being used in homes, offices and schools etc. They keep an eye on
the household budget, whereas in the schools they are assisting in setting question papers
for exams and educating the students. They are one of the main assistants today. In
offices, computer assists professionals to prepare and print letters, documents etc. They
also solve purpose in perfect file maintenance system.

Computer has influenced the business very much. Computer is very useful irrespective of
the size and nature of business. It keeps all the records of business transactions, prepares
and prints business documents, processes the bill of customers and maintains the regular
accounts of business as well. Business professionals not only use them for word processing
or file maintenance but this has also been used to analyse the business activities to take
some vital business decisions.

Micro computer has only one CPU. At present micro computers are still under development.
A book-sized, a phone-sized and even a watch-sized computers are being developed. The
cost of a micro-computer system ranges from Rs. 20,000 to Rs. 1 lac.

With the increasing developments in microprocessor technology, micro computers are
getting smaller and more portable. They are found in different sizes and forms as being
discussed ahead-

n Desktop Computers

n Laptops/Notebooks

n Palmtop Computers

Fundamentals of Desktop Computers
Computers &
Information Technology The most used kind of a personal computer is desktop computers. Desktop, as name
implies is a computer that can be set on a desk and can function from there. It consists
NOTES of CPU (A cabinet where motherboard and other parts are encased), Monitor, Keyboard,
a mouse that we can see as all are separate. Desktop computers cost less but are difficult
to port. Today, you can have a desktop computer with the latest configuration with a price
range between 20-50 thousand rupees.

Figure 1.19 : A Desktop Computer Figure 1.20 : A Laptop

Notebooks and Laptops

Notebooks and Laptops are synonymous though several companies provide more features
with laptops and they are costlier than notebooks. Unlike desktop computers, notebooks
and laptops have nothing separate. All input, output and processing devices are housed in
a case that seems like a travelling briefcase. Usually while travelling and sitting in a chair
notebooks are operated keeping them on your lap, hence, called Laptop (lap + top).
Notebooks and Laptops weigh less than one kilogram. They are costlier than a desktop
computer but can be ported easily. As this is portable means you can carry it with yourself
anywhere, this is highly private. Notebooks and Laptops have battery pack that provides
you normally 4-5 hours power backup when there is no electricity.

Palmtop Computers

Palmtop computers are the most portable personal computers and can be held in your
palm. They can be said pocket computers also though the term is not prevalent officially.
Palmtop computers are now available in several forms. They can be Tablet PCs and PDAs.

Tablet PCs

Tablet PC is a highly portable that houses all the features of a laptop computer. However,
it is much lighter than a laptop and uses a stylus, also called a digital pen, to input
instructions. Users can directly tap or write instructions on the screen. Your Table PCs have
in-built microphones and special software for receiving input in oral form. You can use it
as a CPU as some of the models have facility to connect to a traditional (desktop) keyboard
and a monitor.

Personal Digital Assistant

Personal Digital Assistant is a hand-held personal computer like Tablet PCs and supposed
to be a kind of a palmtop computer. PDAs are coming with several features like camera,
cellphones, music players etc. It is as small as a calculator and can be used for taking notes,
displaying addresses and telephone numbers, appointments and so on. PDAs come with
a pen that the users can use to input instructions directly. PDAs also come with very small
in-built keyboards to input text and microphones for voice inputs. (Figure 1.18)

20

Figure 1.21 : A Tablet PC Figure 1.22 : A Personal Digital Assistant

Workstations Know the Computer
NOTES
Workstations are like micro computers but much powerful
than those and are specially used for running complex Figure 1.23 : A
programs. These are single user computers having a lot of Workstation
features of personal computer . Their processing speed is
like mini computers. These powerful machines are greatly
used by the scientists, engineers and other professionals.
They are very expensive.

However, PCs are not far different from the workstations.
They are also getting highly powerful and equipped with
advanced graphics and communication capabilities.

Mini Computers

These are medium-sized computers. They possess more work efficiency in comparison to
micro computers.

Mini computers are more expensive than a micro computer and one cannot think of
purchasing a mini computer for personal use. These computers are generally useful for
small or medium-sized companies. More than one person can use this computer at a time.
Mini computers possess multiple CPUs. They have bigger memory and higher speed than
micro computers but less than that of Mainframe. They are cheaper than Mainframe.

Figure 1.24 : A Mini Computer 21

In medium-sized companies, mini computer has great importance. It is also possible to
install microcomputer for each person in a company, but it will be a costlier affair. So a
centralized computer system (Mini computer) is the best bet in this case.

In a medium-sized company mini-computer can suffice following purposes:

n Employees payroll.
n Maintenance of books of accounts.
n Cost Analysis.
n Sales supervision.
n Production Planning.

Some other important uses of mini computer are in Passenger Reservation System and
Banking Transaction System.

The first mini-computer was PDP-8 which was equivalent to a refrigerator in size. It was
worth $18000 and manufactured by DEC-Digital Equipment Corporation in 1965.

Mainframe Computers

These are large computers with bigger storage capacity. These can store huge databases
and can also process the data with more speed. Due to their speed in processing huge
databases, they are being used by big companies, banks etc. as a centralised computer
system. It can continuously work round the clock and hundreds of users can work on them
simultaneously.

Fundamentals of Mainframe can easily be attached to any network and even to micro computers.
Computers & Mainframes are widely used by companies for the following purposes
Information Technology
n To maintain customer details
NOTES n To maintain payment details
n To process bills
n To process notices
n Employees payroll
n To maintain detailed record of

tax etc.

Examples of mainframe are - IBM 4381, Figure 1.25 : A Mainframe Computer
ICL - 39 series or CDC Cyber series.

Super Computers

Super computers are computers with biggest capacity
and highest working speed among all the categories of
computers. It has multiple CPUs arranged and working
parallel to each other.

Figure 1.26 : A Super Computer Figure 1.27 : A File photo
of PARAM-10000

The traditional concept of single stream processing of data and program is called, "Von
Neumann Concept". But super computers work on "Non-von Neumann concept". In
a super computer, a CPU consists of many ALU, and each ALU is assigned a specific
process, working parallel.

Super computers are used in the following fields :

n In the mapping of the human genome

n In modelling nuclear fission and other complex processes

n In weather forecasting

n In other big research programmes

n In space research and space exploration

In all the aforementioned fields, calculations and processes require high level accuracy
and can only be achieved by super computers. Super computers are the costliest
computers. Their costs go in millions. The super computer developed by C-DAC in
India is "PARAM" The developed version of PARAM has also been introduced, known
as "PARAM-10000".

Other examples of super computer include Cray - 2, Cray XMP - 24 , Cray T3E and
NEC - 500

Embedded Computers

An embedded computer is a special-purpose computer system designed to perform a
dedicated function. Unlike a general-purpose computer, such as a personal computer,
22 an embedded computer system performs one or a few pre-defined tasks, usually with
very specific requirements, and often includes task-specific hardware and mechanical

parts not usually found in a general-purpose computer. Since the system is dedicated Know the Computer
to specific tasks, design engineers can optimize it, reducing the size and cost of the NOTES
product. Embedded systems are often mass-produced, benefitting from economies of
scale. Check Your Progress :
4. What are Attributes of the
Physically, embedded systems range from portable Figure 1.28 : An Embedded
devices such as digital watches and MP3 players, to Computer being used in First Generation Com-
large stationary installations like traffic lights, factory Traffic Control System puter ?
controllers, or the systems controlling nuclear power 5. On the basic of size com-
plants. In terms of complexity embedded systems run puter can be classfied
from simple, with a single microcontroller chip, to into—
very complex with multiple units, peripherals and 6. What do you understand by
networks mounted inside a large chassis or enclosure. Palmtop Computers ?
7. What is Super Computer ?
Mobile phones or handheld computers share some elements with embedded systems,
such as the operating systems and microprocessors which power them, but are not truly 23
embedded systems themselves because they tend to be more general purpose, allow-
ing different applications to be loaded and peripherals to be connected.

Fundamental uses of computers

______________________________________________________________________________________

In modern times, computer has become an essential element. Everybody in the world
is influenced by computers whether he is a President of a nation, a clerk or a common
man. Neither a national census activity of a nation nor effective railway reservation
system can be done without computers, accurately. Universities and Educational Institutions
prepare marksheets of students in minimum possible time with the help of computers.

Many organisations rely totally on the computers for their day-to-day activities. Banks
are controlling their bilateral transactions, using computers, accurately and efficiently.
Telecommunications are fully computerised. Daily TV serials and other programmes are
edited using computers and transmitted to us by satellite which is also a computer
regulated device.

India is a developing country and facing lots of economic problems such as
unemployment. But computers and related technologies have opened a lot of
opportunities in India. India is one of the main software exporter nations in the world,
hence leading to plenty of employment opportunities in this field.

Uses of computers in different fields are being discussed as follows –

Household and Personal Use

When, micro computer was developed in 1970, the household and personal use of
computer could only be imagined. But today it has become a crystal clear truth. We
can use various types of computers in different sizes and models for our personal use,
in households as well. These can be kept on the desk or can be carried along in the
office briefcase. Few household uses are mentioned below:

n In Kitchen : Microwave ovens do have electronic
processor and memory. Some other kitchen appliances
do have both of the above.

n Computerized Cars : Modern cars have computerised
controls. They also have voice recognising locking system.
They can also alert on low volume of fuel storage.They
can control few superficial changes as per users' wish.
They also drive by navigating electronic road map of a
city in-built in them.

n Computerised Homes : Modern houses are now being Figure 1.29 : A model
built as computer controlled premises. Computers in of computerized car
such buildings identify guests and visitors and also entertain
them. They also irrigate the lawns, When one is not at
home, they also control the temperature of the house.

Fundamentals of n Personal Robot Servants : Robots are not confined to the factories and heavy
Computers & duties alone but they can also be used as house-keepers. Robot is nothing but a
Information Technology computerised machine man.

NOTES n Home Banking & Shopping : Electronic Fund Transfer (EFT) is the system which
gives us the liberty to manage our banking transactions sitting at home. We can
24 pay to shops, banks, travel agencies using personal computer and Internet.

n Modern Cottage Industries : Information has become a saleable thing, due to high
level evolution of computers. This gave rise to some computer based cottage industries.
DTP (for Desk Top Publishing) is a good earning resource for unemployed youths. With
which the publishing work with the help of computer can be performed at home.
Cable-operators use computers to link their device to satellite.

Computers in Education

To enhance the use of computer it was introduced in education, firstly by John Kenery
in 1960 when he developed computer language BASIC. This language got a great response
and became part of curriculum of Dart Mouth College.

Today computer and education are complementary to each other. Importance and application
of computer in education is as mentioned below :

n Learning about computer : One biggest application of computer is education of
computer related subjects viz., Computer Science, Computerised Information System,
Computer Operations, Programming Languages, Internet, E-commerce etc.

n Computer as a teacher : Few softwares are also available which act as teacher
for students. Such a software is CAI-Computer Assisted Instructor which makes
computer a teacher.

This software provides students a Figure. 1.30 : Learning from computers
mathematical problem. If students
solve it properly, it accepts the
answer and grades it accordingly.
But if the student gives wrong
answer, it suggests the solved
answer on the screen and further
gives similar questions until the
student is thorough with that. After
completion of the whole exercise,
computer can also print the
marksheet for the student.

Another software - CMI (Computer Managed Instruction) gives access to the student
to read a variety of books online. They can share their writings with other student
fellows. Hence information does not remain confined to one computer system. Hence
CMI is also called Electronic University.

Using VCD in computer, we can watch documentaries which enhance our knowledge
about different subjects.

n Problem solving : Computer is a good tool to make complex and tough problems
simpler and easier during studies. Computers can collectively analyse the solutions
given by many persons and promptly give the best suitable answer.

n Computers in Training and Examinations : Today many reputed Institutions are
running on-line courses. You can be trained by Microsoft Corporation, Sun Corporation
on their products. You can sit for the examinations conducted by them on-line and
having passed them can obtain a degree from them. Magnetic Ink Recognition in such
a technology which can check the answer sheets of Banking and other objective
exams with unique speed and precision.

Computers in Entertainment Know the Computer
NOTES
Today computer is the largest and the most entertaining device. If a voting is taken
among the educated class. I think, people will vote in favour of it as the greatest means 25
of entertainment. Directly or Indirectly, computer, today is the largest entertainer. I was
quite amazed when I logged on to youtube.com, a few months ago. I got to listen
their all the songs and videos I wanted to have and I can bet that, there would hardly
exist a musical store larger than this in any corner of the world. Major areas of
entertainment are being described in which computer has become essential.

n Games : Using computers we can play a lot of interesting games which also help
in enhancing the mental ability of the player.

n Movies : Computer has got deep roots in recreation industry. Many photographic
effects, musical effects, action effects are induced in movies using computers. Animation
in movies looks so enchanting and lively that one can't differentiate between an
animation and movie of living characters. In movie JURASSIC PARK, the extinct
Dynasaurs were shown; that was made possible by using some specialized software,
such as 3D-studio Max.

n Music : A special musical instrument called Electronic Synthesiser records voices,
produces various instrumental compositions and can store them for later uses with the
help of computers only.

n Arts and Graphics : Using some computer softwares, we can draw and paint
figures. Such softwares are Photoshop and Paintbrush.

Computers in Science and Medicine

Science and medicine are such fields where computers are essential today. The
applications are as follows :

n Science : Computer is essentially required in weather forecasting. It first records
the present climatic conditions and then compares it with the past climatic conditions
to give some conclusions. As input data quantity is huge, super computers are used
for this purpose.

Computers are heavily used in Space Exploration. Computers navigate the spaceships
and also calculate distance and other vital computations for heavenly bodies.

This work can only be done by computers accurately.

One very important application is "simulation". It is a technique, in which, virtual
models of objects like buildings, cars, aeroplanes, missiles, spacecrafts are made and
are then tested for competence. It is a general practice of testing missiles, without
using them actually. This technique of simulation is also called Computer Aided
Designing or CAD.

Computer Simulation

Computer simulation is the discipline of designing a model of an actual or theoretical
physical system, executing the models on a digital computer, and analyzing the execution
output. Simulation embodies the principle of 'learning by doing.' The use of simulation
is an activity that is as natural as a child who plays a role. Chidren understand the world
around them by simulation with most of their interaction with other people, animals
and objects.

Simulation is often used in the training of civilian and military personnel. This usually
occurs when it is prohibitively expensive or simply too dangerous to allow trainees to use
the real equipment in the real world. In such situations they will spend time learning
valuable lessons in a safe virtual environment. Often the convenience is to permit
mistakes during training for a safety critical system.

Fundamentals of
Computers &
Information Technology

NOTES

Fig. 1.31 : A soldier tests out a heavy-wheeled-vehicle driver simulater

n Medicine : Computers are also being used for making us more healthier so that
we can live a long life. Computers have following applications in medicines :

➪ Computer Assisted Diagnosis : It is a diagnosing facility in which hardware

and related softwares help doctors diagnose and test the patient properly with
definite results. In this, symptoms of a patient are fed into computer, and a
special software analyses and compares them with the symptoms of the patients
checked in the past, stored in a database to conclude out the exact disease.

➪ Computer Tomography : This is also called CAT-Scanning. In this technique,

a combination of X-ray devices, computer hardware and software are used to
scan three dimensional view of organs of internal body . This helps physician
cure diseases with more accuracy.

Fig. 1.32 : Computed Tomography

➪ Computerised Life-Support System : This is primarily a nursing aid system. This

system continuously monitors the conditions of a serious patient by keeping an
eye on his pulse rate, blood pressure and other vital changes during the course
of his treatment. If it observes some fatal changes in the body of a patient, it
alarms the nursing staff. This is also regulated by computers only.
Computer is also a boon for physically incapable persons. Some portable computers
have been developed which can be given command by voice. These types of
competence can be greatly useful for blinds.
Information Technology
Due to the advancement in computers, a new stream has also been evolved known as
Information Technology and popularly known as IT.
n Internet : It is a global network of computers. We can access any required
information, sitting at home on a single click of mouse. Any kind of information
related to politics, games, sports, cinema, music, health & medicines, sciences, art
and culture etc. can be obtained from this international network.
26 To know about the sites of our interest we can use Search Engines. Some popular
search engines are Google, Alta-vista, Lycos, Yahoo, Mamma etc. The web search

engines can search websites of our interest by getting a single keyword from user. Know the Computer
Almost all websites are prefixed by "www" which means "world wide web". NOTES

n e-business : Computer is an electronic device and operates electronically. Hence, 27
business transactions which are made through computers are called electronic transactions
and constitute e-business.

Biometric Security Systems

This is a security system in which physical traits of a person can be recognised by
physiological devices of computers.

Computers in future

One major necessity has been realised in the computer field, like there should be such
computers can receive command through voice and confirm us after completing the
job itself. Hence future computers will be highly user friendly. Research teams world
wide are engaged in developing "talking computers" which can take orders from user
during conversation and can confirm by speaking. One of the pioneering company in
this competition is "MIT". MIT has proposed an "Oxygen System." This has been
proposed that for "Oxygen System" unique hardwares and softwares will be developed.
This effort is being made to make computing as omnipresent as Oxygen. The basis of
this system is a device called Handy-21. Handy-21 will look like cellular phone, having
a small screen, a camera, an infrared detector and a computer etc. This will be a
multipurpose machine.

The second technology of Oxygen System is Enviro-21. The Enviro-21 will be connected
to the surrounding environment through sensor cameras, phones and faxes.

In Oxygen System a new microchip called "RAW" will be used. This is used as a unique
chip which does not have a definite circuit inside. The circuit of the chip will be of the
kind, that can be controlled by softwares. Hence the new computing model is commonly
known as RAW and this would be the first kind of computer in which hardware will be
regulated by software.

Summary

______________________________________________________________________________________

● Computer is an electronic machine that performs arithmetic and logical operations
as well.

● Strengths of computers include speed, automation, accuracy, storage capacity,
versatility, diligence and reliability.

● Weaknesses of computers include lack of intelligence and common sense. In addition,
computer is unable in self-protection.

● Electronic Fund Transfer is the system that gives us the liberty to manage our banking
transactions from home.

● In 1801, a French weaver Joseph Jacquard invented a loom which was able to give
pattern and design, automatically, to the fabric.

● Beginning of the nineteenth century was a golden era in the history of computers.

● Charles Babbage developed "Difference Engine" in 1822.

● In 1833, Charles Babbage, developed an advanced version of "Difference Engine"
called Analytical Engine.

● In year 1896, Hollerith established a company "Tabulating Machine Company", this
company was engaged in making punch card machines.

Fundamentals of ● IBM developed "Automatic Sequence Control Calculator" in 1944.
Computers &
Information Technology ● ABC means Atanasoff-Berry Computer. It was the first electronic digital computer.

NOTES ● In year 1946, Eckert and Mauchly developed a computer, named ENIAC.

28 ● ENIAC was 100 feet long, 10 feet high and weighing around 80 tonnes. It was
having 18000 vacuum tubes and used to consume 140 Kilowatt of energy.

● Period for Different generation of computers are as under :

First generation - 1946-1956

Second generation - 1956-1964

Third generation - 1964-1971

Fourth generation - 1971-Present

Fifth generation - Present-Future

● Second generation computers were having main logic element - transistors-instead
of vacuum tubes.

● EDVAC stands for Electronic Discrete Variable Automatic Computer.

● Transistors were developed by William Shockley in 1947.

● Third generation computers were having IC as logic element instead of transistors.

● Super Computer developed by India is PARAM.

● Workstations are more powerful machines than micro computers, however incorporate
many features of those computers.

● Embedded computers are small, simple devices that are often used to control other
devices.

● Mini Computers have multiple CPUs.

● Examples of mainframe are IBM-4381, ICL-39 series, CDC Cyber Series.

● Super computers work on "Non-von Neumann principle."

● In Super Computer, a CPU has many ALUs.

Answers to Check Your Progress :

1. A computer is an electronic machine that performs arithmetic and logical opera-
tions. In other words, computer can be defined as a machine that can be used for
manipulating data according to a list of instructions.

2. Strengths of Computer :
• Good Speed
• Automotion
• Accuracy in output
• High storage capacity
• Versatility
• Reliability.

3. Limitations of Computers :
• Lack of Intelligence

• Lack of Common Sense Know the Computer
• Unable in Self Protection. NOTES
4. Attributes of the First Generation :
• Vacuum Tubes 29
• Punch Card for Input/Output
• Magnetic Drum Internal Memory
• Limited Application
• Programming in Machine and Assembly Language.
5. Classification on the basis of size – This classification has following categories :
• Micro computers
• Workstations
• mini computers
• mainframe computers
• super computers
• embedded computers
6. Palmtop Computers–Palmtop computers are the most portable personal computers and
can be held in your palm. They can be said pocket computers also though the term is
not prevalent officially. Palmtop computers are now available in several forms. They can
be Tablet PCs and PDAs.
7. Super Computers–Super computers are computers with biggest capacity and highest
working speed among all the categories of computers. It has multiple CPUs arranged and
working parallel to each other.

Exercise

______________________________________________________________________________________

1. What is a computer ?
2. Write a detailed account on evolution of computers.
3. Who is called the father of computer science ?
4. Write strengths and weaknesses of computers.
5. Elaborate fundamental uses of computers.
6. Explain different generations of computers.
7. Differentiate between analog and digital computer.
8. How many types of computers are there on the basis of application? Explain them

in details.
9. What are super computers ? What are they being used for ?
10. Differentiate between micro computers and mini computers. Write a short note on

embedded computers.
11. Why do people need to be computer literate today ?
12. What do you understand by versatility of computers.

Fundamentals of 13. Computer works as a foolish servant of yours. Explain.
Computers & 14. How are computers useful in medical examinations ?
Information Technology 15. What do you understand by computer Simulation ?
16. Tell about the Analytical Engine and Difference Engine of Charles Babbage.
NOTES 17. Why is Blaze Pascal called the father of computer science ?
18. Which generation of computers vaccume tube was used in ?
19. Write the names of a few first generation computers.
20. Write the names of a few second generation computers ?
21. Write a short essay an 'Abacus'.
22. What is in-built computer ? Tell the names of our three devices in which in-built

computers are used.

30

2 Personal Computer Personal
Computer
The Chapter Covers :
NOTES
n Introduction
n Personal computer
n Uses of personal computers
n Components of personal computers
n Evolution of pcs
n Developments of processors
n Architecture of pentium iv
n Configuration of pc
n Summary
n Exercise

Introduction

______________________________________________________________________________________

Personal Computer is a term that anybody is hardly unfamiliar with. Personal computer and
Micro Computer are likely interchangeably used terms. Personal computer probably has
been coined for a computer that is limited to use for a single hand. Though it is still vague
for a personal computer is an ordinary micro computer and used in an office it remains
hardly personal to an individual. This chapter serves you information about different dimen-
sions of a personal computer.

31

Fundamentals of Personal Computer
Computers &
Information Technology ______________________________________________________________________________________

NOTES A personal computer (PC) is a microcomputer whose price, size, and capabilities make it
useful for individuals. The term was popularized by Byte magazine, as well as Apple
32 Computer with the Apple II in the late-1970s and early-1980s, and afterwards by IBM with
the IBM Personal Computer. Personal computers are also known as home computers.
Often, the term “Personal Computer” is used exclusively for computers running a Microsoft
Windows operating system, however erroneous. Any microcomputer that is used for
personal causes or for small purposes like wordprocessing, accounting and running general
applications running any software like Linux etc. may be termed as a personal computer.

During the 1990s, the power of personal computers increased radically, blurring the for-
merly sharp distinction between personal computers and multi-user computers, such as
mainframes. Today higher-end computers often distinguish themselves from personal com-
puters by greater reliability or greater ability to multitask, rather than by brute CPU ability
alone.

Uses of Personal Computers

______________________________________________________________________________________

Personal computers are normally operated by one user at one time to perform general
purpose tasks such as word processing, Internet browsing, Internet faxing, e-mail and other
digital messaging, multimedia playback, computer game play, computer programming, etc.
The user of a modern personal computer may have significant knowledge of the operating
environment and application programs, but is not necessarily interested in programming nor
even able to write programs for the computer. Therefore, most software written primarily
for personal computers tends to be designed with simplicity of use, or “user-friendliness”
in mind. However, the software industry continuously provides a wide range of new
products for use in personal computers, targeted at both the expert and the non-expert
user. In short, uses of personal computers include:

n Running a single operating system

n Typing a letter using a common word processor like MS-Word, Adobe PageMaker,
OpenOffice.org etc.

n Maintaining accounts or generating graphs, charts and sheets using spreadsheet
like MS-Excel, etc.

n Making presentations using MS-PowerPoint

n Using Database Management System and Relational Database Management
System

n Using Internet services like WWW, FTP, Telnet etc.

n Using general purpose applications like Tally, Customized Softwares etc.

n Using desktop publications packages like CorelDraw, Photoshop etc.

Components of Personal Computers

______________________________________________________________________________________

A personal computer mainly consists of an input device, an output device, a CPU and
additional devices like modem, scanner printer etc. They are briefly discussed ahead.

To know about the various components of personal computers, we need to know about
both the Internal and External part. Here the internal ones stand for those components
which are inside the CPU cabinet Motherboard, RAM, HardDisk, Video Card, Power
Supply are inside the CPU cabinet which we can't see. Likewise, in the front part of CPU
cabinet we see Floppy Disc Drive and CD or DVD Drive. In the rear part, there are some

important connections which links the internal components of the CPU to other Personal
peripherals. These components are as follows : Computer

u Monitor u Motherboard NOTES
u Main Memory u Hard Disk
u Expansion Card u Computer Power Supply
u Video Card u Optical Disk Drive
u Mouse u Keyboard
u Sound Card u Parallel Port
u Network Card u Universal Serial Bus

Fig. 2.1 : Internal parts Fig. 2.2 : External and internal parts of
of CPU cabinet the drives attached to the computer

Motherboard

The motherboard (or mainboard) is the primary circuit board inside a personal computer.
Many other components connect directly or indirectly to the motherboard. Motherboards
usually contain one or more CPUs, supporting circuitry - usually integrated circuits (ICs)
providing the interface between the CPU memory and input/output peripheral circuits,
main memory, and facilities for initial setup of the computer immediately after being
powered on. In many portable and embedded personal computers, the motherboard
houses nearly all of the PC’s core components. Often a motherboard will also contain
one or more peripheral buses and physical connectors for expansion purposes.

Figure 2.3 : Various types of connecters Figure 2.4 : Motherboard
at the rear part of CPU cabinet

What is a daughterboard ? 33

A daughterboard or daughtercard is a circuit board meant to be an extension or
daughter of a motherboard (or mainboard) or occasionally another card. In particular,
daughter boards have plugs, sockets, pins, connectors or other attachments for other

Fundamentals of boards, which is what differentiates them from a
Computers & standard expansion board such for PCI. In addition,
Information Technology daughterboards usually have only internal connec-
tions within a computer or other electronic device
NOTES rather than any external ones and usually access the
motherboard directly rather than through a com-
34 puter bus.

Main memory

A PC’s main memory (i.e., its ‘primary store’) is fast storage that is directly accessible
by the CPU, and is used to store the currently executing program and immediately
needed data. PCs use semiconductor random access memory (RAM) of various kinds
such as DRAM or SRAM as their primary storage. Main memory is much faster than
mass storage devices like hard disks or optical discs, but is usually volatile, meaning
it does not retain its contents (instructions or data) in the absence of power, and is
much more expensive for a given capacity than is most mass storage. Main memory
is generally not suitable for long-term or archival data storage.

Hard Disk

A hard disk drive (HDD), commonly referred to as a hard drive or hard disk, is a non-
volatile storage device which stores digitally encoded data on rapidly rotating platters
with magnetic surfaces.

HDDs were originally developed for use
with computers. Today, applications for
HDDs have expanded beyond computers
to include digital video recorders, digital au-
dio players, personal digital assistants, digi-
tal cameras, and video game consoles. Use
of HDDs also be found in mobile phones
from Samsung and Nokia. (Figure 2.5)

Expansion Card Figure 2.5 : Harddisk

An expansion card (also expansion board, Figure 2.6 : Expansion Card
adapter card or accessory card) is a printed
circuit board that can be inserted into an ex-
pansion slot of a computer motherboard to add
additional functionality to a computer system.
One edge of the expansion card holds the
contacts that fits exactly into the slot. They
establish the electrical contact between the
electronics (mostly integrated circuits) on the
card and on the motherboard. (Figure 2.6)

Computer Power Supply

In desktop computers, the power supply is a box Figure 2.7 : An SMPS
inside the computer. It is an important part of
the computer because it provides electrical power
in a form that is suitable for every other compo-
nent inside or attached to the computer in order
for it to work. In portable computers (such as
laptops) there is usually an external power brick
which converts AC power to one DC voltage
(most commonly 19v), and further DC-DC con-
version occurs within the laptop to supply the
various DC voltages required by the other com-
ponents of the portable computer. (Figure 2.7)

Video Card Personal
Computer
A video card, also referred to as a graphics accelerator card, display adapter,
graphics card, and numerous other terms, is an item of personal computer hard- NOTES
ware whose function is to generate and output images to a display.

The term is usually used to refer to a separate, dedicated expansion card that is
plugged into a slot on the computer’s motherboard, as opposed to a graphics controller
integrated into the motherboard chipset.

Some video cards offer added functionalities, such as video capture, TV tuner adapter,
MPEG-2 and MPEG-4 decoding or even FireWire, mouse, light pen or joystick connec-
tors.

Figure 2.8 : Graphics card with description of various parts

With their help you can link more tham one monitors which you must have seen in
a music recording studios. This card is used to operate one dimensional two dimen-
sional and three dimensional graphic programs.

Every motherboard supports a definite range of Video Card format, therefore, before
buying it decide whether it is as per the motherboard.

Today, many computers don't have Video Expansion Cards. In its place the graphics
processing unit on motherboard is directly integrated on the motherboard. It lowers
the cost of computers, but such a graphics system is less powerful. It can suit average
business and domestic users. High Graphic capacity or the people having interest in
latest games need to add video card from outside. The names of NVIDIA corporation,
A.T.I. Technologies, Matrox are the names of popular Video Card Makers.

Sound Card

It is a hardware unit of Figure 2.9 : Sound Card with the description of 35
computer- which is fit- different parts.
ted on the Mainboard
as Expansion Card. It
turns the analog sym-
bols received from the
microphone into digital
form to be stored into
computer memory. In
addition a Sound Card
turns digital symbols
into analog form and
sends it to speaker as
output.

Fundamentals of Optical Disc Drive
Computers &
Information Technology An optical disc is a flat, circular, usually polycarbonate disc whereon data is stored
in the form of pits (or bumps) within a flat surface, usually along a single spiral
NOTES groove that covers the entire recorded surface of the disc. This data is generally
accessed when a special material on the disc (often aluminium) is illuminated with
a laser diode. The pits distort the reflected laser light.

The information on an optical disc is stored sequentially on a continuous spiral track
from the innermost track to the outermost track. An acronym for Optical Disc Drives
is ODD.

Parallel Port

Parallel Port is a kind of interface that links so many parts of computers and is found
on the same. It is also known as Printer Port. IEEE 1284 defines the bi-directional
version of standard Port. Before USB arrived the parallel interface was also used to
access numerous peripheral devices (external devices) apart from printer. Zip Drives
and scanner were the first devices which ap-
plied parallel interface which were followed in
external modems, sound card, webcams, game
pads, joy-sticks and external disk drives and
CD-Rom Drives.

Many manufactures of Personal Computer and Figure 2.10 : Parallel Port
Laptop consider parallel interface a legacy port
and is no more in use now. Parallel adapters
are available for the use of Parallel printer of
USB system.

Network Card

Network Card is also known as network adapter, LAN adapter or Network Interface
Card. It is a part of computer Hardware which has been made to connect the
computer with computer network. It works as physical layer, i.e. O.S.I. first layer and
data link layer it means OSI Second Layer device. It provides physical access to
networking media and provides lower-level addressing through the use of MAC ad-
dress. With its help the users can communicate with each-other through wire or
without wire.

Though, other network technologies are available but Ethernet has expanded its area
since the middle of 1990. Every Ethernet has a unique 48-bit serial number of network
card- which is also called MAC Address which is stored in the ROM of the Card. Every
computer of Ethernet network must have a unique MAC Address Card. Any two cards
ever built cannot share the same addresses. This task is accomplished by Institute of
Electrical and Electronic Engineers (IEEE). This Institution is responsible for allocating
unique MAC Address to the Vendors of Network Interface Controllers.

36 Fig. 2.11 : Network card

Universal Serial Bus Personal
Computer
Universal Serial Bus is called U.S.B. in short. U.S.B. has been designed to link the
peripherals of computers with the help of only one standardised interface socket. With NOTES
its help the external devices may be linked without re-booting the computer. It
increases plug and play capabilities. One of its features is, it provides lower-energy
consumption devices with power without any external power-supply. Besides, with its
help, several devices can be linked to computers and run without setting up Greater-
specific driver.

The purpose of Universal Serial Bus is to free the users from serial and parallel ports.
USB can link computer peripherals like mouse, key-board, personal digital assistant,
Game Pads, Joy-stick, Scanners, Digital Camera, Printer, Personal Media Player and
Flash Driver. For many devices out of these. USB has become standard connection
mode, USB has been specifically prepared for Personal Computers but it is also being
used in other devices such as Personal Digital Assistant and Video Game Consoles.

Figure 2.12 : Universal Serial Bus

Monitor

Technically, monitor is known as Visual Display Unit. It is also called a computer
display. Monitor is a piece of electrical equipment which displays viewable images
generated by a computer without producing a permanent record. This is usually either
a cathode ray tube or some form of flat panel such as a TFT or LCD display. The
monitor comprises of the display device, circuitry to generate a picture from electronic
signals sent by the computer, and an enclosure or case. Within the computer, either
as an integral part or a plugged-in interface, there is circuitry to convert internal data
to a format compatible with a monitor. (Figure 2.13)

Figure 2.13 : Monitor Check Your Progress :
1. What are basic componets
Mouse
of computers ?
A mouse (plural mice or mouses) functions as a pointing device by detecting two- 2. What is sound card ?
dimensional motion relative to its supporting surface. Physically, a mouse consists of 3. Define Network Card.
a small case, held under one of the user’s hands, with one or more buttons. It 4. What is parallel port ?
sometimes features other elements, such as “wheels”, which allow the user to per-
form various system-dependent operations, or extra buttons or features can add more 37
control or dimensional input. The mouse’s motion typically translates into the motion
of a pointer on a display.

Fundamentals of The name mouse, coined at the Stanford Research Institute, derives from the
Computers & resemblance of early models (which had a cord attached to the rear part of the
Information Technology device, suggesting the idea of a tail) to the common eponymous rodent.

NOTES Keyboard

38 A computer keyboard is a peripheral partially modelled after the typewriter
keyboard. Keyboards are designed for the input of text and characters and also
to control the operation of a computer.

Physically, computer keyboards are an arrangement of rectangular or near-rectangular
buttons, or “keys”. Keyboards typically have characters engraved or printed on the keys.
In most cases, each press of a key corresponds to a single written symbol. However, to
produce some symbols requires pressing and holding several keys simultaneously or in
sequence. Other keys do not produce any symbol, but instead affect the operation of
the computer or the keyboard itself.

Roughly 50% of all keyboard keys produce letters, numbers or signs (characters). Other
keys can produce actions when pressed, and other actions are available by the simul-
taneous pressing of more than one action keys.

Evolution of PCs

______________________________________________________________________________________

PC's came into existence after many years of the development of Micro-processor. In
earlier versions of PC's, all the tasks were performed on a Floppy Disk. Then Hard Disk
was invented and we got a relatively more durable device which could store more data.
The development of PC has taken place as follows :

(i) Personal Computer : First IBM-PC was a computer having microprocessor as Intel-
8086. It was an 8 bit processor which was best suited to IBM PC requirement at that
time. The main job of this processor was to store data, memory address and points
of instruction. This micro processor was having 14 resistors to carry out data transfer
and data processing. The storage capacity of this processor was 128 to 640 KB. It was
having 1 to 2 floppy drives. Such computers had no Hard Disk and the speed of
calculation was 8 Mega Hz. It had 1 MB memory. The data bit size was 8 bits and
the address bit was of 20 bits.

(ii) PC-XT : In this computer, a new processor 8088 was used. The storage capacity was
640 KB and if had an 8 bit microprocessor. It also had 1 to 2 floppy drives. But the
exclusive characteristic of this PC was Hard Disk Drive attached to it, and computation
speed was 10-12 MHz. Hard disk storage capacity was 1 MB. The size of data bus
was also 8 bits and size of address bus was 20 bits.

(iii) PC-AT : These PCs were having microprocessor named 80286. It had some additional
features, one of which was speedy program processing. It was much speedier than
8086. The storage capacity of these computers was around 1 MB to 2 MB. It was also
having 1 to 2 floppy drives. These computers were also having hard disks which could
work at 16-20 MHz. and maximum capacity was 16 MB. The size of databus was 16-
20 bits and the address bus was 24 bits. Table 2.1 lists some vital information on these
PCs.

Name Storage Capacity Microprocessors No. of FDDs HDD Speed
8+ MHz
PC 128 to 640 KB 8086 1 to 2 No 10-12 MHz
10-12 MHz
PC-XT 640 KB 8088 1 to 2 Yes

PC-AT 1 MB to 2 MB 80286 1 to 2 Yes

Table 2.1 : Features of different PCs

Developments of Processors Personal
Computer
______________________________________________________________________________________ NOTES

Micro computers or Personal computers are all about microprocessors. In olden times, 39
computers were like a big truck and wires used in those computers were in length equal
to the distance between Delhi and Kolkata. With the advent of micro-processor, comput-
ers got desksized, lapsized, palmsized and now can be embedded into your wrist watch.
There have been a number of micro-processors that helped in making more portable and
faster computers. Although, today there are several processor manufactures namely Motorala,
AMD, etc. But, Intel had pioneered in manufacturing processor and even today it stands
first.

Intel 4004

It was the world’s first microprocessor, released in 1971. The 4004 contained 2300
transistors (compared with 5.5 million in the 1996 Pentium Pro) and was intended for
use in a calculator. It processed data in 4 bits, but its instructions were 8 bits long.
Program and Data memory were separate, it had 1 kilobyte of data memory and a
12-bit PC for 4K of program memory. There were also sixteen 4-bit (or eight 8-bit)
general purpose registers. The 4004 had 46 instructions.

Intel 4040

This was the enhanced version of the Intel 4004, adding 14 instructions, larger (8
level) stack, 8 kbyte program memory and interrupt abilities (including shadows of the
first 8 registers).

Intel 8008

A microprocessor intended for use as a terminal controller, and similar to the Intel
4040. The 8008 had a 14-bit PC and addressing and an eight level internal stack. It
was followed by the Intel 8080.

Intel 8080

This was successor to the Intel 8008. The 8080 had a 16-bit address bus and an 8-
bit data bus. It had seven 8-bit registers (six of which could also be combined as three
16-bit registers), a 16-bit stack pointer to memory which replaced the 8008’s internal
stack and a 16-bit program counter. It also had 256 I/O ports (so I/O devices could
be connected without needing to allocate any addressing space as is required for
memory mapped devices) and a signal pin that allowed the stack to occupy a separate
bank of memory. Shortly after the 8080, the Motorola 6800 was introduced.

Intel 8086

A sixteen bit microprocessor chip used in early IBM PCs. The Intel 8086 was a version
with an eight-bit external data bus. The Intel 8086 was based on the design of the
Intel 8080 and Intel 8085 (it was source compatible with the 8080) with a similar
register set, but was expanded to 16 bits.

Intel 8088

An Intel 8086 with 16-bit registers and an 8-bit data bus. The 8088 was the processor
used in the original IBM PC.

Intel 80186

A microprocessor developed by Intel circa 1982. The 80186 was an improvement on
the Intel 8086 and Intel 8088. As with the 8086, it had a 16-bit external bus and was
also available as the Intel 80188, with an 8-bit external data bus. The initial clock rate
of the 80186 and 80188 was 6 MHz. They were not used in many computers, but
one notable exception was the Mindset, a very advanced computer for that time. They
were used as embedded processors.

Fundamentals of Intel 80188
Computers &
Information Technology A version of the Intel 80186 with an 8 bit external data bus (instead of 16 bit).
This makes it cheaper to connect to peripherals.
NOTES
Intel 80286
40
Also 286 or i286. was a microprocessor developed by Intel. The 80286 processor
had a 16-bit data bus and incorporates a memory management unit that allowed
a limited amount of multitasking. The 80286 only had a segmented MMU while
the later processors add a paged MMU “behind” the segmented one. The 80286
was the processor in the IBM PC AT personal computer.

Intel 80386

This was the successor to the Intel 80286 microprocessor. It was the first Intel
processor with 32-bit data and address busses. It could have addressed four gigabytes
(2^32 bytes) of memory; however, 16 megabytes was a typical maximum in IBM
PCs. The 386 allowed multiple application programs to run at the same time (when
running under 386-specific operating systems) using “protected mode”.

Intel 80386SX

This was a lower-speed version of the Intel 80386. It used a 16-bit data bus instead
of a 32-bit data bus. It had a 24-bit address bus. It was faster than the 286, and more
importantly, like the full-size 386, provided more flexibility in running existing DOS
applications.

Intel 486

Known as “i486”, “iAPX 80486”, and “Intel DX4” but usually just “486”. A range of
Intel CISC microprocessors which was part of the Intel 80x86 family of processors.

The 486s were very similar to their immediate predecessor, the Intel 80386DX. The
main differences were that the 486 had an optimised instruction set, had an on-chip
unified instruction and data cache, an optional on-chip floating-point unit (FPU), and
an enhanced bus interface unit. These improvements yielded a rough doubling in
performance over an Intel 80386 at the same clock rate. The successor to the 486
was the Pentium.

Pentium

It was Intel’s superscalar successor to the 486. It had two 32-bit 486-type integer
pipelines with dependency checking. It could have executed a maximum of two
instructions per cycle. It did pipelined floating-point and performs branch prediction.
It had 16 kilobytes of on-chip cache, a 64-bit memory interface, 8 32-bit general-
purpose registers and 880-bit floating-point registers. It was built from 3.1 million
transistors on a 262.4 mm^2 die with ~2.3 million transistors in the core logic. Its
clock rate was 66MHz, heat dissipation was 16W, integer performance was 64.5
SPECint92, floating-point performance 56.9 SPECfp92.

It was called “Pentium” because it was the fifth in the 80x86 line. The successors
were the Pentium Pro and Pentium II.

Pentium Pro

The Pentium Pro had an internal RISC architecture with a CISC-RISC translator, 3-way
superscalar execution, and out-of order execution (or “speculative execution”, which
Intel calls “Dynamic Execution”). It also featured branch prediction and register renam-
ing, and was superpipelined (14 stages).

The Pentium Pro was optimised for 32-bit software and ran 16-bit software slower than
the original Pentium. The successor was the Pentium II.

Pentium II Personal
Computer
Intel Corporation’s successor to the Pentium Pro. The Pentium II could execute all NOTES
the instructions of all the earlier members of the Intel 80x86 processor family.
There were four versions targetted at different user markets. The Celeron was the 41
simplest and cheapest. The standard Pentium II was aimed at mainstream home
and business users. The Pentium II Xeon was intended for higher performance
business servers. There was also a mobile version of the Pentium II for use in
portable computers.

All Pentium II processors had Multimedia Extensions (MMX) and integrated Level
One and Level Two cache controllers. Additional features included Dynamic
Execution and Dual Independent Bus Architecture, with separate 64 bit system and
cache buses. Pentium II was a superscalar CPU having about 7.5 million transistors.

Pentium III

The microprocessor that was Intel Corporation’s successor to the Pentium II,
introduced in 1999 with a 500 MHz clock rate. The Pentim III is very similar to
the Pentium II in architecture. Its external bus can be clocked at 100 or 133 MHz.
It can have up to 512 KB of secondary cache buses, and it comes in various
packages including SECC2 and FC-PGA.

Some other important facts related to processors have been presented in the
following table with the year of processor, the width of the bus, the speed of the
clock and the number of processor.

Year Processor Bus width Speed of the clock Transistor
1971
1974 4004 4 bits 740 Khz 2300
1979
1982 8080 8 bits 2 MegaHz. 6000
1985
1989 8088 16 bits Up to 8 MHz 29000
1993
1995 80286 16 bits Up to 12 MHz 134000
1998
1998 80386 32 bits Up to 33 MHz 275000
1999
2000 80-486 32 bits 100 MHz 1]600]000

Pentium (Real) 64 bits 200 MHz 33 lakh

Pentium (Pro) 64 bits 200 MHz and more 55 lakh

Pentium Pro 64 bits 233 MHz and more 75 lakh

Xeon 64 bits 400 MHz and more 75 lakh and more

Pentium III 64 bits 400 MHz and more 95 lakh and more

Pentium IV 64 bits 1.5 GigaHz and more 4 crores 2 lakh
and more

Table 2.2 : Development of Processors

Architecture of Pentium IV

______________________________________________________________________________________

The Intel Pentium 4 Processor is designed to deliver Tip :
performance across usages—such as image processing, Pentium term has been
video content creation, games and multimedia—where derived from the Greek
end-users can truly appreciate the performance. With a Pent that stands for five
PC based on the Intel Pentium 4 Processor with HT and the Latin ium that
Technology, you get advanced performance and stands for ending. It is a
multitasking capabilities for today’s digital home and blend of two roots.
digital office applications.

Fundamentals of This is a seventh-generation x86 architecture microprocessor produced by Intel and was
Computers & the company’s first all-new CPU design since the Pentium Pro of 1995. Unlike the
Information Technology Pentium II, Pentium III, and various Celerons, the architecture owed little to the Intel
P6 design. The “NetBurst” microarchitecture featured a very deep instruction pipeline,
NOTES with the intention of scaling to very high frequencies. It also introduced the SSE2 SIMD
instruction set for faster integer and 64-bit floating-point computation. Later Pentium
42 4 models integrated technological advances such as Hyper-threading, a feature to make
one physical CPU appear as two logical and virtual CPUs.

The original Pentium 4, codenamed “Willamette”, launched with models at 1.4 and
1.5 GHz and was released in November 2000 on the Socket 423 platform, and later
Socket 478 from 1.5 GHz to 2.0 GHz. Notable with the introduction of the Pentium
4 was the comparatively fast 400 MT/s FSB. It was actually based on a 100 MHz clock
wave, but the bus was quad-pumped, meaning that the maximum transfer rate was
four times that of a normal bus, so it was considered to run at 400 MT/s.

As is traditional with Intel’s flagship chips, the Pentium 4 also came with a low-end
Celeron version (often referred to as Celeron 4) and a high-end Xeon version intended for
SMP configurations. Nearly 5 years after the introduction of the original Pentium 4 CPUs,
a dual core version, called the Pentium D, was released.

Development of the Pentium 4 line of processors was officially halted on July 27, 2006.
Intel’s main focus was then shifted to the Intel Core 2 family of processors.

What is NetBurst?

The Intel NetBurst Microarchitecture, called P68 inside Intel, was the successor to the P6
microarchitecture in the x86 family of CPUs made by Intel. The first one to use this
architecture was the Willamette core, released in late 2000. This was the first of the
Pentium 4 CPUs, and all subsequent Pentium 4 variants have also been based on NetBurst.
In mid 2001, Intel released the Foster core, which was also based on NetBurst, thus
switching the Xeon CPUs to the new architecture as well. Pentium 4 based Celeron CPUs
also use the NetBurst architecture.

NetBurst is sometimes referred to as the Intel P7, Intel 80786, or i786 architecture when
comparing to previous generations. These are not official names. P7 was in fact used
internally at Intel for what became the Itanium architecture.

The NetBurst architecture includes features such as “Hyper Pipelined Technology” and
“Rapid Execution Engine” which are first in this particular microarchitecture.

Configuration of PC

______________________________________________________________________________________

If you go to a computer shop and ask for a personal computer. The first question the
salesman would asks is about the configuration of PC you are looking for. The latest
configuration of a computer should likely be this –

n A 3.4 GHz Intel Pentium 4 Processor
n 1 MB of L2 cache memory
n 1 GB of D2 RAM ( Random Access Memory )
n A 300 GB Hard Disk
n 2 Magabytes L2 Cache Memory
n Graphics Card 256 Megabyte
n Intel Motherboard.
In the above PC configuration, the Intel Pentium Processor is the CPU. However, to get
the best deal on configuration, go to a leading shop in your area and ask what configuration
is in vogue. Alternatively, you can see ads of different companies for the latest features
and configuration as you can see one ad from Dell describing features and configurations
in a news-paper as shown in Figure.

Personal
Computer

NOTES

Figure 2.14 : An ad revealing the latest configuration of PC.

Summary

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l Personal computer is a term that we all are familiar with.
l A personal computer (PC) is a microcomputer whose price, size and capabilities

make it useful for individuals.

l Personal Computers are also known as home computers.
l Personal computers are normally operated by one user at one time to perform

general purpose tasks.

l A personal computer mainly consists of an input device, an output device, a
CPU and some additional devices like modem, scanner, printer etc.

l Monitor is technically known as Visual Display Unit.

l Monitor is a piece of electrical equipment which displays viewable images
generated by a computer without producing a permanent record.

l The motherboard is the primary circuit board within a personal computer.

l Many other components connect directly or indirectly to the motherboard.
l A PC's main memory is fast storage that is directly accessible by the CPU and

is used to store the currently executing program and immediately needed data.

l A hard disk drive (HDD), commonly referred to as a hard drive or hard disk,
is a non-volatile storage device which stores digitally encoded data on rapidly

rotating platters with magnetic surfaces.

l An expansion card is a printed circuit board that can be inserted into an
expansion slot of a computer motherboard to add additional functionally to a

computer system.

l First IBP-PC was a computer having microprocessor as Intel 8086 and was an Check Your Progress :
8 bit processor and best suited to IBM PC that time. 5. What is key-board ?
6. What was the world’s first
l The storage capacity in PC-XT was 640 KB and was a 8-bit microprocessor.
micro processor ?
l PC-AT had 80286 microprocessor and storage capacity was 1 MB - 2 MB. 7. What features includes in
l Intel 4004 was the world's first microprocessor released in 1971.
NetBurst Architecture ?
l The best bet to have information on the latest configuration is either to go to
43
a leading computer store or see the ads floated in the newspapers by the
companies.

Answer of the Check your progress :

1. These components are as follows :

• Monitor • Motherboard

• Main Memory • Hard Disk

Fundamentals of • Expansion Card • Computer Power Supply
Computers & • Video Card • Optical Disk Drive
Information Technology • Mouse • Keyboard
• Sound Card • Parallel Port
NOTES • Network Card • Universal Serial Bus

44 2. Sound Card–It is a hardware unit of computer- which is fitted on the Mainboard as
Expansion Card. It turns the analog symbols received from the microphone into digital
form to be stored into computer memory. In addition a Sound Card turns digital symbols
into analog form and sends it to speaker as output.

3. Network Card–Network Card is also known as network adapter, LAN adapter or Net-
work Interface Card. It is a part of computer Hardware which has been made to connect
the computer with computer network.

4. Network Card–Network Card is also known as network adapter, LAN adapter or Net-
work Interface Card. It is a part of computer Hardware which has been made to connect
the computer with computer network.

5. Keyboard–A computer keyboard is a peripheral partially modelled after the typewriter
keyboard. Keyboards are designed for the input of text and characters and also to control
the operation of a computer.

6. Intel 4004 –It was the world’s first microprocessor, released in 1971. The 4004 con-
tained 2300 transistors (compared with 5.5 million in the 1996 Pentium Pro) and was
intended for use in a calculator. It processed data in 4 bits, but its instructions were 8
bits long.

7. The NetBurst architecture includes features such as “Hyper Pipelined Technology” and
“Rapid Execution Engine” which are first in this particular microarchitecture.

Exercise

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1. What is a personal computer ? Describe all of its components.
2. What is a microprocessor ? Write a note on evolution of microprocessor in detail.
3. Describe the classification of PCs in detail.
4. Write uses of personal computers.
5. What is a daughterboard ?
6. What is an expansion card ?
7. Write a brief note on Computer Power Supply.
8. How can you get best deal on getting a PC with the latest configuration? Prepare

a chart for the latest configuration of a PC from three different companies and
compare the prices also.
9. What is parallel port ?
10. What is Universal Serial Bus?
11. What is Ethernet Card ?
12. Tell about Video Card.
13. Write about Power Supply.
14. What is the difference between Mother board and Daughter Board ?
15. What is Monitor technically called. as?
16. What is the difference between Universal Serial Bus and Parallel Port ?
17. Why is Main Memory called the primary memory of computer ?
18. How many transistors were there in Pentium II ?
19. What uses the speed of clock in Pentium II ?
20. What is Netburst ?
21. What is done by Institute of Electrical and Electronic Engineers related to
Network ?

3 Boolean Algebra Boolean Algebra
And Logic Gates And Logic Gates

NOTES

The Chapter Covers :

n Introduction
n Boolean Algebra
n Binary Valued Quantities
n And Operator
n OR Operator
n NOT Operator
n Basic Postulates of Boolean Algebra
n Therorems of Boolean Algebra
n De Morgan's Theorems
n Reducing Boolean Expression by their Simplifications
n Proving the Equations of Boolean Expressions By Truth Table
n Principle of Duality
n Standard Forms
n Basic Logic Gates
n Use of Logic Gates in Circuits
n Karnaugh Maps

Introduction

______________________________________________________________________________________

Boolean Algebra is the algebraic structure of Abstract Algebra in which required properties
of set operations and logic operations. Expecially it contains intersection, union and comple-
ment set operations and AND,OR and NOT logic operations. Logic gates act on signals
which express true or false. Logic gates help in building a circuit. This chapter deals with
the concerned topics in detail.

45

Fundamentals of Boolean Algebra
Computers &
Information Technology ______________________________________________________________________________________

NOTES Let us know what Boolean Algebra is. It is a part of Algebra. Boolean logic is a
It was invented by an British Mathematician Jeorge Boole. complete system of logical
46 It is used to simplify the electronic digital circuits. With its processes. It was named
help, one writes expressions for complex Circuits and these after an English
are turned into simple expressions through some simple mathematician, George
rules. These simple expressions remove complexities from Boole. He was the first
the circuits. The main principle of Boolean algebra is that to explain the algebraic
an equation has either True or False value. Digit 1 or letter system of logic in mid
T express truth while digit 0 or letter F, express False. 19th century. Boolean
logic is extremely useful
According to Boolean Algebra there are two probabilities in electronic computer
for a statement. First it is True or Second it is False. hardware and software.
Boolean algebra has only two possible values True or
False. That is why it's also called Two state Algebra. Let
us analyze the following statements carefully.

n The capital of India is New Delhi.

n 2 and 2 add up to 5.

n The sun rises in the east.

Here statements 1 and 3 are True, while statement 2 is False. Here different logics
have been supplied in the statements. Therefore the True and False conditions of the
statements are called Logical Values. The Logical values True and False are called
Logical constant.

By adding two statements, we can frame a new statement and this new statement
again will have logical constants as its value. Such as-

______________________________________________________________________________________

"The moon revolves round the earth." AND
"The earth moves round the sun."

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Here "AND" has linked two statements. If these two added statements are true, then the
entire statement will be true. If any of the statements added by AND is False, the entire
statement will be False. such as-

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"The capital of India is Jaipur AND Jaipur is a city in Rajasthan."

______________________________________________________________________________________

Here the entire statement is not True as the capital of India is not Jaipur. Boolean Algebra
turns set of statements into symbols and expressions. These symbols and Expressions are
manipulated on the basis of some rules.

Binary Valued Quantities

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You know that in Binary Number System two digits 1 and 0 are used. In Boolean Algebra,
the values of the statements True and False are expressed by 1 and 0 respectively. 1 and
0 are called Binary Valued Quantities. It means the values of Boolean algebraic expressions
1 and 0 are called Binary Values Quantities. Where 1 stands for True and 0 stands for
False. Claude Shannon and other mathematicians used the symbolic logics of Boolean
Algebra for the analysis of switching circuits at Bell Laboratories in 1938. Switch is a device
made to continue or discontinue electric transmission in an electric circuit. If the switch
is ON, then the current flows in the circuit and if it is OFF, the current flow stops. The
circuit interconnecting such switches is called switching circuit. A switch is ON or OFF in
two conditions. When it is ON it allows the flow of current and if it is OFF the current
flow halts. (See figure 3.1)

(a) Open Boolean Algebra
(b) Close And Logic Gates

Figure 3.1 : Current Flow NOTES

In the statements of Boolean algebra these complex circuits are expressed. These 47
expressions are simplified by the Basic Postulates of Boolean Algetra. The simple circuits
can be prepared based on these simplified expressions which increases the efficiency
of the circuits and saves time.

AND operator

______________________________________________________________________________________

Focus on the circuit given in the following picture. It has two switches S1 and S2 connected
to a battery and a bulb. The two situations possible for the flow of electric current in the
bulb are as follows -

Switch S1 Switch S2

Bulb B

Current Flow

Figure 3.2 : AND Operator

Situation 1 S1 = Open and S2 = Open, current will not flow in the bul B.
Situation 2 S1 = Open and S2 = Closed, current will not flow in the bul B.
Situation 3 S1 = Closed and S2 = Open, current will not flow in the bul B.
Situation 4 S1 = Closed and S2 = Closed, There will be current flow in the bul B.

These results can be expressed in table 3.1 in a tabular form :

S1 S2 B Truth table is a kind of
Closed Closed mathematical table
Current Flow which is used to deter-
No No mine whether an ex-
No Yes No pression is true or false
Yes No No in the logic
Yes Yes No
Yes

Table 3.1 : The results of AND operator

You know that a logic has only two possible values Yes or No. If Yes is replaced by 1 and
No is replaced by 0, the simple form of Table 3.1 is obtained as table 3.2.

S1 S2 B
Closed Closed
Current Flow
0 0
0 1 0
1 0 0
1 1 0
1

Table 3.2 : The results of AND operator

Fundamentals of Table 2, expresses a simple statement the value of B will be True while S1 and S2 are
Computers & True. This statement can be written mathematically like this -
Information Technology
B = S1 AND S2
NOTES
When a new statement is prepared by adding two statements it is called a compound
48 statement. The above said compound statement is added with AND. Here AND is an
operator which adds two logics. AND operator is called Logical AND.

A Table which expresses all the possibilities of a switching circuit as Binary Valued Quantity
1 and 0 is called Truth Table. Table 3.2 is an example of a Truth Table. Here B is affected
with S1 and S2 conditions. If S1 and S2 conditions are taken as Input the output is seen on
the Bulb B. In the truth table the effect of all the possible inputs on the switching circuits
is seen on the output. For AND two inputs a and b and output c have been given in Truth
Table 3...

a bc

0 00
0 10
1 00
1 11

Table 3.3 : Truth Table for AND

OR Operator

______________________________________________________________________________________

Let's focus on switching circuit in the Switch S1
following picture in which two switches
S1 and S2 have been connected parallelly →
and electric bulb B and battery have
been added in a series. →

Switch S2

Figure 3.3

For this circuit the following situations of electric transmission are possible -

Situation 1. S1 = Open or (OR) S2 = Open S1→
Situation 2.
There is no current flowing in bulb B. S2

S1 = open (OR) S2 = closed there →
is current flow on bulb B.
Current flow
Situation 3. S1 = closed (OR) S2 = open
There is current flow in bulb B. Figure 3.4

Situation 4- S1 = closed (OR) S2 = closed
The current flows in bulb B.

Current flow
S1

S2

Figure 3.5

For the situations, the truth table for the switching circuit will be as follows : Boolean Algebra
And Logic Gates
S1 S2 B
NOTES
0 00
0 11 49
1 01
1 11

Table 3.4

It is clear from the table given above that if any of S1 or S2 or (OR) both are closed, the
current will flow in the bulb. It can be written mathematically in the following way-

B = S1 OR S2

Here OR works as a logic operator in the compound statement. That is why it is called
logical OR. Similarly, if the Inputs are a and b, then in their switching circuit, the truth
table affecting the 0 output will be as follows :

a b0

0 00
0 11
1 01
1 11

Table 3.5

NOT Operator

______________________________________________________________________________________

Let's focus on the switching circuit given below. Here a switch S has been connected in
such a way that it will open only when current flows in the bulb otherwise if it is closed,
there will be no current flow in the bulb.

Battery B bulb

S1, switch

Table 3.6

The following conditions are possible for this switching circuit -

Condition 1. S = open, current flow in the bulb B.

Condition 2. S = closed, no current flow in the bulb B.

The truth table for this switching circuit will be as follows :

SB

01
10

Here, it is noteworthy that only one switch S has been fitted in this switching circuit. The
current will flow in the bulb only when the switch S is open. Therefore the opposite result
is obtained. It can be written mathematically in the following way :

B = NOT S

Here the NOT operator is called logical NOT. The other names of NOT operator are
Negation and Inverse operator.

Fundamentals of If the input is a, all the possibilities of the output are expressed the following way in
Computers & truth table given below :
Information Technology
a Result
NOTES
10
50 01

If the statement has been expressed by a then if NOT operation is performed upon
it the acquired result is expressed by a'. It means if there is an input a its NOT operation
can be expressed with a'.

a' = NOT a

Basic Postulates of Boolean Algebra

______________________________________________________________________________________

In boolean algebra, to simplify the complex expressions there are some accepted facts and
postulates. These rules are the basis of boolean algebra. By simplifying boolean expressions,
electronic circuits are prepared for an operation. If the boolean expression for an operation
is complex, the electronic circuit prepared on its basis is also complex. Therefore it is
necessary to simplify boolean expressions.

Suppose, S is a set whose elements are boolean amounts, the following postulates will be
accepted.

If a, b, c, 0, 1 are the elements of set S, it means a, b, c, 0, 1 ∈ S.

Rule 1. (i) a + b ∈ S

(ii) a . b ∈ S

(iii) a' ∈ S

(iv) b' ∈ S

This rule will also be considered true for more then two elements.

Rule 2. Logical operations OR and AND will be as follows -

a+b=b+a

a.b=b.a

Rule 3. The Distrubutive Rule distrubites 't' on '.' or .' on '+'.

a . (b + c) = a . b + a . c

a + b . c = (a + b) . (a + c)

Rule 4. a + (b + c) = (a + b) + c = a + b + c

a . (b . c) = (a.b).c = a . b . c

Rule 5. a+ 0 = 0 + a = a

a.1=1.a=a

Rule 6. If a ∈ S, its complement a' ∈ S will be as follows :

a + a' = 1 = a' + a

a . a' = 0 = a' . a

Thus, the set S includes operations of OR, AND and NOT. The above given postulates
are also called Huntington's (1904) postulates.