MODULE 1

Overview of Computing: Evolution and History,

Components of a Computer System: CPU, Memory, Input/ Output Devices
Operating Systems: Types, Functions, and Features
Data Representation: Binary, Hexadecimal, ASCII-------→ SEMINAR TOPIC
Software vs Hardware: Understanding the Difference
Introduction to Networking: LAN, WAN, Internet

Overview of computing
The first counting device was used by the primitive people. They used sticks, stones and bones
as counting tools. As human mind and technology improved with time more computing devices
were developed. Some of the popular computing devices starting with the first to recent ones
are described below;
Abacus
The history of computer begins with the birth of abacus which is believed to be the first
computer. It is said that Chinese invented Abacus around 4,000 years ago.
It was a wooden rack which has metal rods with beads mounted on them. The beads were
moved by the abacus operator according to some rules to perform arithmetic calculations.
Abacus is still used in some countries like China, Russia and Japan.
Napier's Bones
It was a manually-operated calculating device which was invented by John Napier (1550-1617)
of Merchiston. In this calculating tool, he used 9 different ivory strips or bones marked with
numbers to multiply and divide. So, the tool became known as "Napier's Bones. It was also the
first machine to use the decimal point.
Pascaline
Pascaline is also known as Arithmetic Machine or Adding Machine. It was invented between
1642 and 1644 by a French mathematician-philosopher Biaise Pascal. It is believed that it was
the first mechanical and automatic calculator.
Pascal invented this machine to help his father, a tax accountant. It could only perform addition
and subtraction. It was a wooden box with a series of gears and wheels. When a wheel is rotated
one revolution, it rotates the neighboring wheel. A series of windows is given on the top of the
wheels to read the totals.
Generations of Computers
A generation of computers refers to the specific improvements in computer technology with
time. In 1946, electronic pathways called circuits were developed to perform the counting. It
replaced the gears and other mechanical parts used for counting in previous computing
machines.
In each new generation, the circuits became smaller and more advanced than the previous
generation circuits. The miniaturization helped increase the speed, memory and power of
computers. There are five generations of computers which are described below;
First Generation Computers
The first generation (1946-1959) computers were slow, huge and expensive. In these
computers, vacuum tubes were used as the basic components of CPU and memory. These
computers were mainly depended on batch operating system and punch cards. Magnetic tape
and paper tape were used as output and input devices in this generation;
Some of the popular first generation computers are;
o ENIAC ( Electronic Numerical Integrator and Computer)
o EDVAC ( Electronic Discrete Variable Automatic Computer)
o UNIVACI( Universal Automatic Computer)
o IBM-701
o IBM-650
Second Generation Computers
The second generation (1959-1965) was the era of the transistor computers. These computers
used transistors which were cheap, compact and consuming less power; it made transistor
computers faster than the first generation computers.
In this generation, magnetic cores were used as the primary memory and magnetic disc and
tapes were used as the secondary storage. Assembly language and programming languages like
COBOL and FORTRAN, and Batch processing and multiprogramming operating systems were
used in these computers.
Some of the popular second generation computers are;
o IBM 1620
o IBM 7094
o CDC 1604
o CDC 3600
o UNIVAC 1108
Third Generation Computers
The third generation computers used integrated circuits (ICs) instead of transistors. A single IC
can pack huge number of transistors which increased the power of a computer and reduced the
cost. The computers also became more reliable, efficient and smaller in size. These generation
computers used remote processing, time-sharing, multi programming as operating system.
Also, the high-level programming languages like FORTRON-II TO IV, COBOL, PASCAL
PL/1, ALGOL-68 were used in this generation.
Some of the popular third generation computers are;
o IBM-360 series
o Honeywell-6000 series
o PDP(Personal Data Processor)
o IBM-370/168
o TDC-316
Fourth Generation Computers
The fourth generation (1971-1980) computers used very large scale integrated (VLSI) circuits;
a chip containing millions of transistors and other circuit elements. These chips made this
generation computers more compact, powerful, fast and affordable. These generation
computers used real time, time sharing and distributed operating system. The programming
languages like C, C++, DBASE were also used in this generation.

Fifth Generation Computers

In fifth generation (1980-till date) computers, the VLSI technology was replaced with ULSI
(Ultra Large Scale Integration). It made possible the production of microprocessor chips with
ten million electronic components. This generation computers used parallel processing
hardware and AI (Artificial Intelligence) software. The programming languages used in this
generation were C, C++, Java, .Net, etc.
Some of the popular fifth generation computers are;
o Desktop
o Laptop
o NoteBook
o UltraBook
o ChromeBook
Components of a Computer System
A computer is an electronic device that accepts data, performs operations, displays results, and
stores the data or results as needed. It is a combination of hardware and software resources
that integrate and provide various functionalities to the user. Hardware is the physical
components of a computer, such as a processor, memory devices, monitor, keyboard, etc., while
software is a set of programs or instructions that are required by the hardware resources to
function properly.
Components of a Computer
There are basically three important components of a computer:
1. Input Unit
2. Central Processing Unit(CPU)
3. Output Unit
1. Input Unit:
The input unit consists of input devices that are attached to the computer. These devices take
input and convert it into binary language that the computer understands. Some of the common
input devices are keyboard, mouse, joystick, scanner etc.
• The Input Unit is formed by attaching one or more input devices to a computer.
• A user input data and instructions through input devices such as a keyboard, mouse, etc.
• The input unit is used to provide data to the processor for further processing.
2. Central Processing Unit:
Once the information is entered into the computer by the input device, the processor processes
it. The CPU is called the brain of the computer because it is the control centre of the computer.
It first fetches instructions from memory and then interprets them so as to know what is to be
done. If required, data is fetched from memory or input device. Thereafter CPU executes or
performs the required computation, and then either stores the output or displays it on the output
device. The CPU has three main components, which are responsible for different functions:
Arithmetic Logic Unit (ALU), Control Unit (CU) and Memory registers
A. Arithmetic and Logic Unit (ALU): The ALU, as its name suggests performs mathematical
calculations and takes logical decisions. Arithmetic calculations include addition, subtraction,
multiplication and division. Logical decisions involve the comparison of two data items to see
which one is larger or smaller or equal.
• Arithmetic Logical Unit is the main component of the CPU
• It is the fundamental building block of the CPU.
 • Arithmetic and Logical Unit is a digital circuit that is used to perform arithmetic and
logical operations.
B. Control Unit: The Control unit coordinates and controls the data flow in and out of the
CPU, and also controls all the operations of ALU, memory registers and also input/output units.
It is also responsible for carrying out all the instructions stored in the program. It decodes the
fetched instruction, interprets it and sends control signals to input/output devices until the
required operation is done properly by ALU and memory.
• The Control Unit is a component of the central processing unit of a computer that directs
the operation of the processor.
• It instructs the computer’s memory, arithmetic and logic unit, and input and output
devices on how to respond to the processor’s instructions.
• In order to execute the instructions, the components of a computer receive signals from
the control unit.
• It is also called the central nervous system or brain of the computer.
C. Memory Registers: A register is a temporary unit of memory in the CPU. These are used
to store the data, which is directly used by the processor. Registers can be of different sizes(16
bit, 32 bit, 64 bit and so on) and each register inside the CPU has a specific function, like
storing data, storing an instruction, storing address of a location in memory etc. The user
registers can be used by an assembly language programmer for storing operands, intermediate
results etc. Accumulator (ACC) is the main register in the ALU and contains one of the
operands of an operation to be performed in the ALU.
Memory attached to the CPU is used for the storage of data and instructions, and is called
internal memory The internal memory is divided into many storage locations, each of which
can store data or instructions. Each memory location is of the same size and has an address.
With the help of the address, the computer can read any memory location easily without having
to search the entire memory. When a program is executed, its data is copied to the internal
memory and stored in the memory till the end of the execution. The internal memory is also
called the Primary memory or Main memory. This memory is also called RAM, i.e., Random
Access Memory. The time of access of data is independent of its location in memory, therefore,
this memory is also called Random Access memory (RAM).
• Memory Unit is the primary storage of the computer.
• It stores both data and instructions.
• Data and instructions are stored permanently in this unit so that they are available
whenever required.
3. Output Unit :
The output unit consists of output devices that are attached to the computer. It converts the
binary data coming from the CPU to human understandable form. The common output devices
are monitor, printer, plotter, etc.
• The output unit displays or prints the processed data in a user-friendly format.
 • The output unit is formed by attaching the output devices of a computer.
• The output unit accepts the information from the CPU and displays it in a user-readable
form.
Characteristics of a Computer
1. Speed: Computers can perform millions of calculations per second. The computation
speed is extremely fast.
2. Accuracy: Because computers operate on pre-programmed software, there is no space
for human error.
3. Diligence: They can perform complex and long calculations at the same time and with
the same accuracy.
4. Versatile: Computers are designed to be versatile. They can carry out multiple
operations at the same time.
5. Storage: Computers can store a large amount of data/ instructions in its memory, which
can be retrieved at any point of time.

What is the Computer Software?

Software is a collection of instructions, procedures, and documentation that performs different
tasks on a computer system. We can say also Computer Software is a programming code
executed on a computer processor. The code can be machine-level code or code written for an
operating system.
Examples of software are MS- Word, Excel, PowerPoint, Google Chrome, Photoshop,
MySQL, etc.
Different Types of Computer Software
• System Software: System Software is a component of Computer Software that directly
operates with Computer Hardware which has the work to control the Computer’s
Internal Functioning and also takes responsibility for controlling Hardware Devices
such as Printers, Storage Devices, etc. Types of System Software include Operating
Systems, Language processors, and Device Drivers.
• Application Software: Application Software is the software that works the basic
operations of the computer. It performs a specific task for users. Application Software
includes Word Processors, Spreadsheets, etc. Types of Application software include
General Purpose Software, Customized Software, etc.
Difference Between Hardware and Software
Parameters Hardware Software

Hardware is a physical
part of the computer Software is a set of instructions that tells a
Basic that causes the computer exactly what to do.
Definition processing of data.

Development It is manufactured. It is developed and engineered.

Hardware cannot
The software can not be executed without
perform any task
hardware.
Dependency without software.

Electronic and other

Created by utilizing a computer language to write
Process of materials are used to
instructions.
creating create hardware.

Hardware is tangible
as hardware is a
Software is intangible as we can see and also use
physical electronic
the software but can’t touch them.
device, that can be
Tangible touched.

Hardware typically The software does not wear out with time.
Durability wears out over time. However, it may contain flaws and glitches.

It has four main

categories:
• Input Devices
It is mainly divided into
• Output
Devices • System software
• Storage • Application software.
Devices
• Internal
Types Components.
Parameters Hardware Software

Hardware is not
affected by computer Software is affected by computer viruses.
Virus effect viruses.

It cannot be
transferred from one
place to another It can be transferred via a network means.
electrically through
Transfer the network.

Only machine-level
The program accepts human-readable input,
Machine- language is known to
interprets it in machine-level language, and sends
Level be understood by
it to hardware for additional processing.
language hardware.

If the hardware is
If the software is damaged, its backup copy can
damaged, it is replaced
be reinstalled.
Replacement with a new one.

Dust, overheating,
humidity, and other Overloading, systematic error, major-minor
factors are commonly version error, and other factors are commonly
responsible for responsible for software failures.
Failures hardware failures.

Ex: Keyboard, Mouse,

Monitor, Ex: MS
Printer, CPU, Hard Word, Excel, PowerPoint, Photoshop, MySQL,
disk, RAM, ROM, etc.
Examples etc.

Types of area networks – LAN, MAN and WAN

The Network allows computers to connect and communicate with different computers via
any medium. LAN, MAN, and WAN are the three major types of networks designed to operate
over the area they cover. There are some similarities and dissimilarities between them. One of
the major differences is the geographical area they cover, i.e. LAN covers the smallest
area, MAN covers an area larger than LAN and WAN comprises the largest of all.
Local Area Network (LAN) –
LAN or Local Area Network connects network devices in such a way that personal computers
and workstations can share data, tools, and programs. The group of computers and devices are
connected together by a switch, or stack of switches, using a private addressing scheme as
defined by the TCP/IP protocol. Private addresses are unique in relation to other computers on
the local network. Routers are found at the boundary of a LAN, connecting them to the larger
WAN.
Data transmits at a very fast rate as the number of computers linked is limited. By definition,
the connections must be high-speed and relatively inexpensive hardware (Such as hubs,
network adapters, and Ethernet cables). LANs cover a smaller geographical area (Size is
limited to a few kilometres) and are privately owned. One can use it for an office building,
home, hospital, school, etc. LAN is easy to design and maintain. A Communication medium
used for LAN has twisted-pair cables and coaxial cables. It covers a short distance, and so the
error and noise are minimized.
Early LANs had data rates in the 4 to 16 Mbps range. Today, speeds are normally 100 or 1000
Mbps. Propagation delay is very short in a LAN. The smallest LAN may only use two
computers, while larger LANs can accommodate thousands of computers. LAN has a range up
to 2km. A LAN typically relies mostly on wired connections for increased speed and security,
but wireless connections can also be part of a LAN. The fault tolerance of a LAN is more and
there is less congestion in this network. For example A bunch of students playing Counter-
Strike in the same room (without internet).
Advantages:
• Provides fast data transfer rates and high-speed communication.
• Easy to set up and manage.
• Can be used to share peripheral devices such as printers and scanners.
• Provides increased security and fault tolerance compared to WANs.
Disadvantages:
• Limited geographical coverage.
• Limited scalability and may require significant infrastructure upgrades to accommodate
growth.
• May experience congestion and network performance issues with increased usage.
Metropolitan Area Network (MAN) –
MAN or Metropolitan area Network covers a larger area than that covered by a LAN and a
smaller area as compared to WAN. MAN has a range of 5-50km. It connects two or more
computers that are apart but reside in the same or different cities. It covers a large geographical
area and may serve as an ISP (Internet Service Provider). MAN is designed for customers who
need high-speed connectivity. Speeds of MAN range in terms of Mbps. It’s hard to design and
maintain a Metropolitan Area Network.

The fault tolerance of a MAN is less and also there is more congestion in the network. It is
costly and may or may not be owned by a single organization. The data transfer rate and the
propagation delay of MAN are moderate. Devices used for transmission of data through MAN
are Modem and Wire/Cable. Examples of a MAN are part of the telephone company network
that can provide a high-speed DSL line to the customer or the cable TV network in a city.
Advantages:
• Provides high-speed connectivity over a larger geographical area than LAN.
• Can be used as an ISP for multiple customers.
• Offers higher data transfer rates than WAN in some cases.
Disadvantages:
• Can be expensive to set up and maintain.
• May experience congestion and network performance issues with increased usage.
• May have limited fault tolerance and security compared to LANs.
Wide Area Network (WAN) –
WAN or Wide Area Network is a computer network that extends over a large geographical area,
although it might be confined within the bounds of a state or country. WAN has a range of
above 50 km. A WAN could be a connection of LAN connecting to other LANs via telephone
lines and radio waves and may be limited to an enterprise (a corporation or an organization) or
accessible to the public. The technology is high-speed and relatively expensive.
There are two types of WAN: Switched WAN and Point-to-Point WAN. WAN is difficult to
design and maintain. Similar to a MAN, the fault tolerance of a WAN is less and there is more
congestion in the network. A Communication medium used for WAN is PSTN(Public Switched
Telephone Network) or Satellite Link. Due to long-distance transmission, the noise and error
tend to be more in WAN.
WAN’s data rate is slow about a 10th LAN’s speed since it involves increased distance and
increased number of servers and terminals etc. The speed of WAN ranges from a few kilobits
per second (Kbps) to megabits per second (Mbps). Propagation delay is one of the biggest
problems faced here. Devices used for the transmission of data through WAN are Optic wires,
Microwaves, and Satellites. An example of a Switched WAN is the asynchronous transfer mode
(ATM) network and Point-to-Point WAN is a dial-up line that connects a home computer to the
Internet.
Advantages:
• Covers large geographical areas and can connect remote locations.
• Provides connectivity to the internet.
 • Offers remote access to resources and applications.
• Can be used to support multiple users and applications simultaneously.
Disadvantages:
• Can be expensive to set up and maintain.
• Offers slower data transfer rates than LAN or MAN.
• May experience higher latency and longer propagation delays due to longer distances
and multiple network hops.
• May have lower fault tolerance and security compared to LANs.

What is Internet?
The Internet is the foremost important tool and the prominent resource that is being used by
almost every person across the globe. It connects millions of computers, webpages, websites,
and servers. Using the internet we can send emails, photos, videos, and messages to our loved
ones. Or in other words, the Internet is a widespread interconnected network of computers and
electronic devices(that support Internet). It creates a communication medium to share and get
information online. If your device is connected to the Internet then only you will be able to
access all the applications, websites, social media apps, and many more services. The Internet
nowadays is considered the fastest medium for sending and receiving information.
History of the Internet
The Internet came in the year 1960 with the creation of the first working model
called ARPANET (Advanced Research Projects Agency). It allowed multiple computers to
work on a single network which was their biggest achievement at that time. ARPANET uses
packet switching to communicate multiple computer systems under a single network. In
October 1969, using ARPANET first message was transferred from one computer to another.
After that technology continues to grow.
How is the Internet Set Up?
The internet is set up with the help of physical optical fiber data transmission cables or copper
wires and various other networking mediums like LAN, WAN, MAN, etc. For accessing the
Internet even the 2G, 3G, and 4G services and the Wifi require these physical cable setups to
access the Internet. There is an authority named ICANN (Internet Corporation for Assigned
Names and Numbers) located in the USA which manages the Internet and protocols related
to it like IP addresses.
How Does the Internet Work?
The actual working of the internet takes place with the help of clients and servers. Here the
client is a laptop that is directly connected to the internet and servers are the computers
connected indirectly to the Internet and they are having all the websites stored in those large
computers. These servers are connected to the internet with the help of ISP (Internet Service
Providers) and will be identified with the IP address.
Each website has its Domain name as it is difficult for any person to always remember the long
numbers or strings. So, whenever you search for any domain name in the search bar of the
browser the request will be sent to the server and that server will try to find the IP address from
the Domain name because it cannot understand the domain name. After getting the IP address
the server will try to search the IP address of the Domain name in a Huge phone directory that
in networking is known as a DNS server (Domain Name Server). For example, if we have the
name of a person and we can easily find the Aadhaar number of him/her from the long directory
as simple as that.
So after getting the IP address, the browser will pass on the further request to the respective
server and now the server will process the request to display the content of the website which
the client wants. If you are using a wireless medium of Internet like 3G and 4G or other mobile
data then the data will start flowing from the optical cables and will first reach towers from
there the signals will reach your cell phones and PCs through electromagnetic waves and if you
are using routers then optical fiber connecting to your router will help in connecting those light-
induced signals to electrical signals and with the help of ethernet cables internet reaches your
computers and hence the required information.
What is an IP Address?
IP Address stands for Internet Protocol Address. Every PC/Local machine is having an IP
address and that IP address is provided by the Internet Service Providers (ISPs). These are some
sets of rules which govern the flow of data whenever a device is connected to the Internet. It
differentiates computers, websites, and routers. Just like human identification cards like
Aadhaar cards, Pan cards, or any other unique identification documents. Every laptop and
desktop has its own unique IP address for identification. It’s an important part of Internet
technology. An IP address is displayed as a set of four-digit like 192.154.3.29. Here each
number on the set ranges from 0 to 255. Hence, the total IP address range from 0.0.0.0 to
255.255.255.255.
World Wide Web (WWW)
The world wide web is a collection of all the web pages, and web documents that you can see
on the Internet by searching their URLs (Uniform Resource Locator) on the Internet.
Difference Between World Wide Web and the Internet
The main difference between the World Wide Web and the Internet are:

World Wide Web Internet

All the web pages and web

documents are stored there on the
The Internet is a global network of computers that is
World wide web and to find all that
accessed by the World wide web.
stuff you will have a specific URL
for each website.
World Wide Web Internet

The world wide web is a service. The Internet is an infrastructure.

The world wide web is a subset of

The Internet is the superset of the world wide web.
the Internet.

The world wide web is software-

The Internet is hardware-oriented.
oriented.

The world wide web uses HTTP. The Internet uses IP Addresses.

The world wide web can be

considered as a book from the The Internet can be considered a Library.
different topics inside a Library.

Uses of the Internet

Some of the important usages of the internet are:
• Online Businesses (E-commerce): Online shopping websites have made our life
easier, e-commerce sites like Amazon, Flipkart, and Myntra are providing very
spectacular services with just one click and this is a great use of the Internet.
• Cashless Transactions: All the merchandising companies are offering services to their
customers to pay the bills of the products online via various digital payment apps like
Paytm, Google Pay, etc. UPI payment gateway is also increasing day by day. Digital
payment industries are growing at a rate of 50% every year too because of the
INTERNET.
• Education: It is the internet facility that provides a whole bunch of educational material
to everyone through any server across the web. Those who are unable to attend physical
classes can choose any course from the internet and can have point-to-point knowledge
of it just by sitting at home. High-class faculties are teaching online on digital platforms
and providing quality education to students with the help of the Internet.
• Social Networking: The purpose of social networking sites and apps is to connect
people all over the world. With the help of social networking sites, we can talk, and
share videos, and images with our loved ones when they are far away from us. Also, we
can create groups for discussion or for meetings.
• Entertainment: The Internet is also used for entertainment. There are numerous
entertainment options available on the internet like watching movies, playing games,
listening to music, etc. You can also download movies, games, songs, TV Serial, etc.,
easily from the internet.