Fundamental of Computer

1762 Pages·2016·28.78 MB·English

Fundamental of Computer
(MCA/PGDCA - 101)

Jaipur National University
Directorate of Distance Education
_________________________________________________________________________________
Established by Government of Rajasthan
Approved by UGC under Sec 2(f) of UGC ACT 1956
(Recognised by Joint Committee of UGC-AICTE-DEC, Govt. of India)
1
Introduction to Computer

STRUCTURE
1.0 Objectives
1.1 Introduction
1.2 Strengths of Computers
1.3 Limitations of Computers
1.4 Fundamental Uses of Computers
1.5 Development of Computers
1.6 Types of Computers
1.7 Generations of Computers
1.8 Summary
1.9 Keywords
1.10 Review Questions
1.11 Further Studies

1.0 Objectives
After studying this chapter, you will be able to:
Discuss the strengths of computers
Explain the limitations of computers
Discuss the fundamental uses of computers
Explain the developments of computers
Define the generations of computers

1.1 Introduction

The word ―computer‖ comes from the word ―compute‖, which means, ―to calculate‖. Hence, people
usually a computer to be a calculating device that can perform arithmetic operations at high speed. In fact
the original objective for inventing a computer was to create a fast calculating machine. However, more
than 80% of work done by computers today is of non-mathematical or non-numerical nature. Hence, to
define computer merely as a calculating device is to ignore over 80% of its functions.

1.2 Strengths of Computers

Increasing popularity of computers has proved that it is a very powerful and useful tool. The power and
usefulness of this popular tool are mainly due to its following characteristics:
1. Automatic. An automatic machine works by itself without human intervention. Computers are automatic
machines because once started on a job, they carry out the job (normally without am human assistance)
until it is finished. However, computers being machines cannot start themselves and cannot go out and find
their own problems and solutions. We need to instruct a computer using coded instructions that specify
exactly how it will do a particular job. Some of the other characteristics of computers (such as speed and
accuracy) are because they are automatic and work on a problem without any human intervention.

2. Speed. A computer is a very fast device. It can perform in a few seconds, the amount of work that a
human being can do in an entire year, if he/she worked day and night and did nothing else. In other words,
a computer can do in a few minutes what would take a man his entire lifetime.
While talking about the speed of a computer we do not talk in terms of seconds or even milliseconds (10-3)
but in terms of microseconds (10-6), nanoseconds (10-9), and even picoseconds (10-12). A powerful computer
is capable of performing several billion (109) simple arithmetic operations per second.

3. Accuracy. In addition to being very fast, computers are very accurate. Accuracy of a computer is
consistently high and the degree of its accuracy depends upon its design. A computer performs even
calculation with the same accuracy.
However, errors can occur in a computer. These errors are mainly due to human rather than technological
weaknesses. For example, errors may occur due to imprecise thinking by a programmer (a person who
writes instructions for a computer to solve a particular problem) or incorrect input data. We often refer to
computer errors caused due to incorrect input data or unreliable programs as garbage-in-garbage-out
(GIGO).

4. Diligence. Unlike human beings, a computer is free from monotony, tiredness, and lack of
concentration. It can continuously work for hours without creating any error and without grumbling.
Hence, computers score over human beings in doing routine type of jobs that require great accuracy. If ten
million calculations have to be performed, a computer will perform the last one with exactly the same
accuracy and speed as the first one.

5. Versatility. Versatility is one of the most wonderful things about a computer. One moment it is
preparing results of an examination, next moment it is busy preparing electricity bills, and in between. It
may be helping an office secretary to trace an important letter in seconds. All that is required to change its
talent is to slip in a new program (a sequence of instructions for the computer) into it. In brief, a computer
is capable of performing almost any task, if the task can be reduced to a finite series of logical steps.

6. Power of Remembering. As a human being acquires new knowledge, his/her brain subconsciously
selects what it feels to be important and worth retaining in memory. The brain relegates unimportant
details to back of mind or just forgets them. This is not the case with computers. A computer can store and
recall any amount of information because of its secondary storage (a type of detachable memory)
capability. It can retain a piece of information as long as a user desires and the user can recall the
information whenever required. Even after several years, a user can recall exactly the same information
that he/she had stored in the computer several years ago. A computer forgets or looses certain information
only when a user asks it to do so. Hence, it is entirely up to the user to make a computer retain or forget
some information.

7. No I Q. A computer is not a magical device. It possesses no intelligence of its own. Its I. Q. is zero at
least until today. It has to be told what to do and in what sequence. Hence, only users determine what tasks
a computer will perform. A computer cannot take its own decision in this regard.

8. No Feelings. Computers are devoid of emotions. They have no feelings and no instincts because they
are machines. Although men have succeeded in building a memory for computer, but no computer
possesses the equivalent of a human heart and soul. Based on our feelings, taste, knowledge, and
experience we often make certain judgements in our day-to-day life whereas, computers cannot make such
judgements on their own. They make judgements based on the instructions given to them in the form of
programs that are written by us (human beings).

1.3 Limitations of Computers

Computer has done this and that. Actually this is not the computer which has done this but the user.
Despite its various features, a computer does have the following limitations:
No Self Intelligence
Today, a computer is able to do a work which is impossible for man. Computers are used to do risky and
dangerous work and where sharp actually is needed. But it does not have any intelligence of its own. It
works according to the instruction only.
No Decision-Making power
Computer cannot take any decision of its own. It does only those tasks which are already instructed to it.
No learning power
Computer has no learning power. Once you give instructions to a computer how to perform a task, the very
task is cannot perform if you do not give it any instructions for the next time. For example, when you are
taught how to solve a problem and if same type of problem is given you to solve, then you can do it.
Emotionless
Computers are emotionless. They do not have emotion, like dislike feelings. They are simply machines
which work as per the instruction given to them.
Curtail human Capabilities
Although computers are great help to human beings, it is commonly felt that we people have become so
dependent on calculator that we cannot make very simple calculation without calculator. Sometimes, find it
difficult to instantly speak out even that telephone number which they use every now and then as they have
got the habit of using them by retrieving the storage.

Caution
Excessive use of computers is causing various type of health injuries such as cervical and back pain, pain
in eye, headache.

1.4 Fundamental Uses of Computers

With technology continuously evolving and intertwining into everyday life, people are using computers for
more and more simple tasks. This is possible thanks in no small part to the continued efforts of computer
manufacturers as well as software designers to simplify computing so that anyone can sit down, power on
the machine and jump right in.

Communication
Thanks to computers and the Internet, the world has gotten much smaller in recent years. Many people use
their computers to keep in touch with friends and family using instant messenger programs as well as
email. A growing communication tool is social networking, with sites like Facebook and Twitter becoming
incredibly popular.

Games
PCs have long served as recreational devices with hundreds of games available each year. Gaming on a PC
can be an expensive hobby, with video cards ranging in price from INR 3,000 to more than 20,000 and
fully equipped gaming PCs costing in excess of INR 75,000 in many cases. For all the top-tier AAA titles,
there are other games that users can find both pre-installed on PCs as well as online.
Entertainment
Almost all computers come with CD or DVD disk drives, which allow you to use the computer as a CD
player or DVD player. Some computers are also capable, with the proper hardware, of viewing and
recording television onto the machine's hard drives. With an Internet connection, users have a nearly
limitless of videos and music available online as well.

Work
Almost every working environment uses computers in one capacity or another. Office buildings use
computers to keep track of everything from pay wages to hours logged, retail stores use computers as cash
registers and industries such as construction and architecture use computers to help design buildings.

1.5 Development of Computers

Necessity is the mother of invention. The saying holds true for computers too. Computers were invented
because of man‘s search for fast and accurate calculating devices.
Basic Pascal invented the first mechanical adding machine in 1642. Later, in the year 1671, Keyboard
machines originated States around 1880 and we use them even today. Around the same period, Herman
Hollerith came up with concept of punched cards that were extensively used as input medium in computers
even in late 1970s. Machines and calculators made their appearance in Europe and America towards the
end of the century.
Charles Babbage, a nineteenth century Professor at Cambridge University, is considered the father of
modern digital computers. In order to have a better idea of the evolution of computers it is worthwhile to
discuss of the well-known early computers. These are as follows:
1. The Mark-I Computer (1937-44). Also known as Automatic Sequence Controlled calculator, this
was the first fully automatic calculating machine designed by Howard A. Aiken of Harvard University in
collaboration with IBM (International Business Machines) Corporation. It was an electro-mechanical
device (used both electronic and mechanical components) based on the techniques already developed for
punched card machines.
2. The Atanasoff-Berry Computer (1939-42). Dr. John Atanasoff developed an electronic machine
to solve certain mathematical equations. The machine was called the Atanasoff-Berry Computer, or ABC,
after its inventor's name and his assistant, Clifford Berry. It used 45 vacuum tubes for internal logic and
capacitors for storage.
3. The ENIAC (1943-46). The Electronic Numerical Integrator And Calculator (ENIAC) was the first
all electronic computer. It was constructed at the Moore School of Engineering of the University of
Pennsylvania, U.S.A. by a design team led by Professors J. Presper Eckert and John Mauchly.
The team developed ENIAC because of military needs. It was used for many years to solve ballistic related
problems. It took up wall space in a 20 x 40 square feet room and used 18,000 vacuum tubes it could add
two numbers in 200 microseconds and multiply them in 2000 microseconds.

Did You Know?
Baron Gottfried Wilhelm von Leibniz of Germany invented the first calculator for multiplication.

4. The EDVAC (1946-52). A major drawback of ENIAC was that its programs were wired on boards
that made it difficult to change the programs. Dr. John Von Neumann later introduced the ―stored
program‖ concept that helped in overcoming this problem. The basic idea behind this concept is that a
sequence of instructions and data can be stored in the memory of a computer for automatically directing
the flow of operations. This feature considerably influenced the development of modern digital computers
because of the ease with which different programs can be loaded and executed on the same computer. Due
to this feature, we often refer to modern digital computers as stored program digital computers. The
Electronic Discrete Variable Automatic Computer (EDVAC) used the stored' program concept in its
design. Von Neumann also has a share of the credit for introducing the idea of storing both instructions and
data in binary form (a system that uses only two digits - 0 and 1 to represent all characters), instead of
decimal numbers or human readable words.

5. The EDSAC (1947-49). Almost simultaneously with EDVAC of U.S.A., the Britishers developed the
Electronic Delay Storage Automatic Calculator (EDSAC). The machine executed its first program in May
1949. In this machine, addition operations took 1500 microseconds and multiplication operation: took
4000 microseconds. A group of scientists headed by Professor Maurice Wilkes at the Cambridge
University Mathematical Laboratory developed this machine.

6. The UNIVAC I (1951). The Universal Automatic Computer (UNIVAC) was the first digital
computer that was not ―one of a kind‖. Many UNIVAC machines were produced, the first of which was
installed in the Census Bureau in 1951 and was used continuously for 10 years. In 1952, the International
Business Machines (IBM) Corporation introduced the IBM-701 commercial computer. In rapid succession,
improved models of the UNIVAC I and other 700-series machines were introduced. In 1953, IBM
produced the IBM-650, and sold over 1000 of these computers.

Did You Know?
UNIVAC marked the arrival of commercially available digital computers for business and scientific
applications and was developed by General Electric Corporation in 1954.

Self Assessment Questions

1. The value of picoseconds is:
(a) 10–6 (b) 10–12
(c) 10–9 (d) None of these.

2. The term GIGO stands for:
(a) garbage-in-garbage-out (b) global-in-global-out
(c) go-in-go-out (d) None of these.

3. Which one is not the strength of the computer?
(a) Automatic machine (b) Fast speed
(c) No learning power (d) Accuracy

4. The average speed of first analytical engine was:
(a) 60 additions per minute (b) 40 additions per minute
(c) 70 additions per minute (d) 80 additions per minute

Exercise: Check Your Progress 1
Note: i) Use the space below for your answer.
Ex1: Search more about the history of computers.
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1.6 Types of Computers

A computer is one of the most brilliant inventions of mankind. Thanks to computer technology, we were
able to achieve storage and processing of huge amounts of data; we could rest our brains by employing
computer memory capacities for storage of information. Owing to computers, we have been able speed up
daily work, carry out critical transactions and achieve accuracy and precision at work. Computers of the
earlier times were of the size of a large room and were required to consume huge amounts of electric
power. However, with the advancing technology, computers have shrunk to the size of a small watch.
Depending on the processing power and size of computers, they have been classified under various types.
Let us look at the classification of computers.

1.6.1 Operational Based
Based on the operational principle of computers, they are categorized as analog, digital and hybrid
computers.
Analog Computers: These are almost extinct today. These are different from a digital computer because an
analog computer can perform several mathematical operations simultaneously. It uses continuous variables
for mathematical operations and utilizes mechanical or electrical energy.

Digital Computers: They use digital circuits and are designed to operate on two states, namely bits 0 and
1. They are analogous to states ON and OFF. Data on these computers is represented as a series of 0s and
1s. Digital computers are suitable for complex computation and have higher processing speeds. They are
programmable. Digital computers are either general purpose computers or special purpose ones. General
purpose computers, as their name suggests, are designed for specific types of data processing while general
purpose computers are meant for general use.

Hybrid Computers: These computers are a combination of both digital and analog computers. In this type
of computers, the digital segments perform process control by conversion of analog signals to digital ones.

1.6.2 Sizes and Processing Powers
This was the classification of computers based on their style of functioning. Following is a classification of
the different types of computers based on their sizes and processing powers.
Mainframe Computers: Large organizations use mainframes for highly critical applications such as bulk
data processing and ERP. Most of the mainframe computers have capacities to host multiple operating
systems and operate as a number of virtual machines. They can substitute for several small servers.

Microcomputers: A computer with a microprocessor and its central processing unit is known as a
microcomputer. They do not occupy space as much as mainframes do. When supplemented with a
keyboard and a mouse, microcomputers can be called personal computers. A monitor, a keyboard and
other similar input-output devices, computer memory in the form of RAM and a power supply unit come
packaged in a microcomputer. These computers can fit on desks or tables and prove to be the best choice
for single-user tasks.

1.6.3 Personal computers
Personal computers come in different forms such as desktops, laptops and personal digital assistants. Let
us look at each of these types of computers.
Desktops: A desktop is intended to be used on a single location. The spare parts of a desktop computer are
readily available at relatively lower costs. Power consumption is not as critical as that in laptops. Desktops
are widely popular for daily use in the workplace and households.
Laptops: Similar in operation to desktops, laptop computers are miniaturized and optimized for mobile
use. Laptops run on a single battery or an external adapter that charges the computer batteries. They are
enabled with an inbuilt keyboard, touch pad acting as a mouse and a liquid crystal display. Their
portability and capacity to operate on battery power have proven to be of great help to mobile users.

Notebooks: They fall in the category of laptops, but are inexpensive and relatively smaller in size. They
had a smaller feature set and lesser capacities in comparison to regular laptops, at the time they came into
the market. But with passing time, netbooks too began featuring almost everything that notebooks had. By
the end of 2008, netbooks had begun to overtake notebooks in terms of market share and sales.
Personal Digital Assistants (PDAs): It is a handheld computer and popularly known as a palmtop. It has a
touch screen and a memory card for storage of data. PDAs can also be used as portable audio players, web
browsers and smartphones. Most of them can access the Internet by means of Bluetooth or Wi-Fi
communication.

Minicomputers: In terms of size and processing capacity, minicomputers lie in between mainframes and
microcomputers. Minicomputers are also called mid-range systems or workstations. The term began to be
popularly used in the 1960s to refer to relatively smaller third generation computers. They took up the
space that would be needed for a refrigerator or two and used transistor and core memory technologies.
The 12-bit PDP-8 minicomputer of the Digital Equipment Corporation was the first successful
minicomputer.

Servers: They are computers designed to provide services to client machines in a computer network. They
have larger storage capacities and powerful processors. Running on them are programs that serve client
requests and allocate resources like memory and time to client machines. Usually they are very large in
size, as they have large processors and many hard drives. They are designed to be fail-safe and resistant to
crash.

Supercomputers: The highly calculation-intensive tasks can be effectively performed by means of
supercomputers. Quantum physics, mechanics, weather forecasting, molecular theory are best studied by
means of supercomputers. Their ability of parallel processing and their well-designed memory hierarchy
give the supercomputers, large transaction processing powers.

Wearable Computers: A record-setting step in the evolution of computers was the creation of wearable
computers. These computers can be worn on the body and are often used in the study of behaviour
modelling and human health. Military and health professionals have incorporated wearable computers into
their daily routine, as a part of such studies. When the users' hands and sensory organs are engaged in other
activities, wearable computers are of great help in tracking human actions. Wearable computers do not
have to be turned on and off and remain in operation without user intervention.

Tablet Computers: Tablets are mobile computers that are very handy to use. They use the touch screen
technology. Tablets come with an onscreen keyboard or use a stylus or a digital pen. Apple‘s iPod
redefined the class of tablet computers.

Exercise: Check Your Progress 2
Note: i) Use the space below for your answer.
Ex1: Discuss about some advance computer generations such as iPod and tablet PCs.
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1.7 Generations of Computers

Generation in computer talk is a step in technology. It provides a framework for the growth of computer
industry. Originally, the term ―generation‖ was used to distinguish between varying hardware technologies
but it has now been extended to include both hardware and software that together make up a computer
system. The custom of referring to computer era in terms of generations came into wide use only after
1964. There are totally five computer generations known till today. Below we describe each generation
along with its identifying characteristics. Although there is a certain amount of overlap between different
generations, the approximate period shown against each are normally accepted. During description of
various computer generations, you will come across several new terminologies and computer jargons that
you may not be able to understand properly. There are Five Generations of Computer given below:
1 First Generation (1942-1955)
2 Second Generation (1955-1964)

Figure 1.1: Electronic devices used for manufacturing computers of different generations.

3 Third Generation (1964-1975)
4 Fourth Generation (1975-1989)
5 Fifth Generation (1989-Present)

Exercise: Check Your Progress 3
Note: i) Use the space below for your answer.
Ex1: Search more about Computer Generation.
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Did You Know?
An integrated circuit (IC) is a small electronic device made out of a semiconductor material. The first
integrated circuit was developed in the 1950s by Jack Kilby of Texas Instruments and Robert Noyce of
Fairchild Semiconductor.

Exercise: Check Your Progress 4
Case Study-Apple Computer
Apple Computer is an American Multinational corporation with a focus on designing and manufacturing
consumer electronics and even develops software products. It was co-founded by Steve Wozniak and Steve
Jobs. Steve Wozniak met Steve Jobs while he was working at Hewlett-Packard. Steve Jobs worked part
time, where he would finish up games that they designed in Grass Valley.
In 1975, the first personal computer kit, the Alistair 8800 was announced. Since Steve Wozniak could not
afford an Alistair 8800 he decided to build his own personal computer by using cheaper chips. As circuit
board alone, it could do more than Alistair. He and Steve Jobs called it Apple I, Jobs handled on marketing
it while Wozniak continued to improve it. By 1977, Wozniak had built Apple II, then he and Jobs decided
to form Apple Computer Inc. when it went public on 1980, its stock value was $117 million, three years
later it was $985 million.
This story of how Apple started is one of my favourite. We watched a film titled ―Pirates of the Silicon
Valley‖ last year that‘s why Apple story is a little familiar for me. We can see that Steve Wozniak is
determined that he will develop a computer even if he was still a child. I can say that if we really put out
hard work and commitment to do something then we can be successful. According to Wozniak, if we try to
start our own company, we must have the highest ethics and be open and truthful about things, not hide.
We must not lead people. Know in your heart that you are a good person with good goals because it will
carry over to our own self-confidence: make our own product better that the average person would.
Questions
1. Who was the founder of Apple Computer?
2. Write the year of first Apple computer.

1.8 Summary

The word computer comes from the word ‗compute‘, which means, to calculate.
Computer generation like First Generation, Second Generation, Third Generation, Fourth Generation
and Fifth Generation.
Computers are emotionless. They do not have emotion, like dislike feelings.
Basic Pascal invented the first mechanical adding machine in 1642.
Charles Babbage, a nineteenth century Professor at Cambridge University, is considered the father of
modern digital computers.

1.9 Keywords

Generation: Originally, the term .generation was used to distinguish between varying hardware
technologies but it has now been extended to include both hardware and software that together make up a
computer system.
Graphical user interface (GUI): It enables new users to quickly learn how to use computers.
Integrated Circuits: They are usually called ICs or chips. They are complex circuits which have been
etched onto tiny chips of semiconductor (silicon). The chip is packaged in a plastic holder with pins spaced
on a 0.1''(2.54 mm) grid which will fit the holes on strip board and breadboards. Very fine wires inside the
package link the chip to the pins.
Medium scale integration (MSI): Medium-Scale Integration is a term used in electronic chip
manufacturing industry. An integrated circuit which contained hundreds of transistors on each chip, called
Medium-Scale Integration (MSI).
Small-Scale Integration (SSI): The first integrated circuits contained only a few transistors. Called Small-
Scale Integration (SSI), they used circuits containing transistors numbering in the tens.

1.10 Review Questions

1. Define a computer? It is also known as a data processor. Explain.
2. Differentiate between data and information. Which is more useful to the people and why?
3. List and explain some important characteristics of a computer.
4. Who is known as the father of modern digital computers?
5. What are the limitations to use the computer?
6. What are the basic uses of computers?
7. Define the types of computers.
8. Which was the first commercially produced computer? When and where it was first installed?
9. Define: IBM, ENIAC, EDVAC, EDSAC, and UNIVAC.
10. Discuss the different generations of computers.

Answers for Self Assessment Questions
1. (b) 2. (a) 3. (c) 4. (a)

1.11 Further Studies
1. Computer Fundamentals by P. K. Sinha