Search Engine Definition

A search engine is a software that is accessed on the internet to assist a user to search its
query on the world wide web. The search engine is helpful as it carries out a systematic
search on the web and displays the results that best match the user’s query.
The results are usually retrieved in the form of a list often referred to as SERPs or Search
Engine Result Pages. These results or information may be links to web pages, or a mix of
images and videos, research papers, newspaper articles, etc.
There are various search engines available, google being the most popular of all. All these
search engines are capable of searching so quickly due to the web crawler.
How does a Search Engine work?
With thousands of informative web pages available on the internet, how does a search
engine display the relevant ones? How does it list these pages on our screen? What are the
criteria? let us look at how to do search engines work.
The search engine follows three steps to execute the query of the user-
Crawling
Indexing
Ranking
The search engine follows these steps to provide relevant results to the user.
Crawling
Discovering new web pages on the internet starts with crawling. All search engines use
these bots called web crawlers or spider bots that follow links to the new webpages present
in the known ones.
They get the information by crawling from site to site. Once the information is collected it is
indexed. While indexing is going on the spider keeps going with discovering new pages.
Once a certain amount of time is spent or base on the amount of data collected, the spider
stops crawling.
Indexing
Once the data is crawled it is sent for indexing-saving data on the database of the search
engine called the index.It is the job of the index to find information related to the query as
soon as possible. This process can be performed quickly by adopting any of these steps-
Stripping out the stop words.
Listing links to other pages.
Listing information about images or embedded media on the page.
Any website has to be indexed to get listed on search results. Sometimes when a query is
entered, the index results are obtained quickly because it has already stored a few website
links containing the keywords.
Ranking
The last step is to rank the results on the SERP. The search engines have their criteria based
on which the search results are listed. These signals or criteria are hidden from the public. It
is the work of the ranking to determine the order of the web links on the results page.
One of the most common doubt is- do all search engines give the same results? And the
answer is, not necessarily. Each search engine has its algorithm, based on which it performs
the search on the web.
These searches are also based on the factors like your location, what was the preference of
other users for the same keyword, what have been your past searches, etc. Therefore, all
the search engines tend to give different search results.
What are the top 5 Search Engines?
Google is of course the leader of search engines with more than 90% of the market share.
So much so that, it has become synonymous with searching on the internet.

What is search engine - Google

Let us look at some of the other most popular search engines apart from Google.

1. Bing (renamed as Microsoft Bing in October 2020)

This one is almost as popular as the google search. Bing is the default search engine of the
windows PC. One might find various similarities between google and bing with result
features like – images, videos, places, maps, and news.
Though Microsoft might have attempted to make it as successful as Google it still holds only
2-3 percent of the total search engine market share.
2. Yahoo
Yahoo used to be one of the most popular sites to visit at one time. It is exclusively provided
by Bing. It is also a default for Firefox users in the United States.
3. Baidu
This one is a popular engine in China. Though not very popular, its shares are increasing
worldwide, according to Alexa. It is available all around the world but only in Chinese.
4. Yandex
Yandex.ru is a popular search engine in countries like Russia, Ukraine, Turkey, etc. Its name
is derived from Yet Another Indexer. It has less than 1 percent market share of the overall
search engine.
5. DuckDuckGo
This not-so-popular search engine has about 0.45 percent of the market share. Its
competitors are also small search engines like Bing and Yahoo. Unlike most search engines it
does not have a search index of its own, instead uses a variety of sources.
In other words, it does not have data of its own and depends on other sites like yahoo, Bing,
etc. But what makes it unique from the lot is that it’s much cleaner and is not full of trash
ads.

Why Search Engines are Important?

Search engines are part of daily life for two types of people.

• Users who search and get information

• Site owners who try to optimize their websites for getting top rank in the search
results.

User do more than billions of searches only on Google to find relevant information. This
opens out a huge scope for businesses and online content publishers to attract people to
their website for free. Search engines follow guidelines and have their own algorithm to
decide the ranking of websites in search results. Optimizing websites for Google and other
search engines is an essential part of any website owner for reaching out the large audience.
The visitors can generate revenue for site owners either through advertisements displayed
on the site or though purchasing products.

Conclusion
There is no such as the best search engine. Though, Google’s algorithm might be superior to
the others it does not mean it will always curate the best results. Various upcoming search
engines are fighting their way into the most popular search engine category. Try all these
search engines yourself and decide which one gives the perfect solutions to your queries.

A search engine is a software system that takes user input and searches a database of
indexed web pages. A browser is a software application that’s used to access web pages
over the internet.

Search Engine vs Browser: What’s the Difference?

Search engines are programs that look through an index of websites on the internet that
correspond to the user’s keywords. Browsers are applications that are used to access web
pages, or HTML files, by making contact with a web server.

Browser: Search Engine:

A software application used to make contact A software system designed to discover
with a web server and view web pages (HTML and return web pages available on the
files). Pages can be either static or dynamic. internet.
The main components of browsers are the user
interface (UI), the browser engine, the Search engines consist of three main parts:
rendering engine, the networking component, the crawler, the search index and the
the UI back end, the JavaScript interpreter and search algorithm.
data storage.
It uses a graphical user interface (GUI) to
visually display web content and enable user Search engines have their own databases.
interaction with the web page.
Browsers will store your browsing history, Search engines usually collect data about
cookies and cache in the memory unless you their users and their search queries. Some
manually clear this data or use a private search engines, such as DuckDuckGo,
browsing mode. refrain from collecting user data.
Popular browsers include Google Chrome,
Famous search engines include Google,
Mozilla Firefox, Internet Explorer, Microsoft
Bing, DuckDuckGo, Yandex, and Yahoo.
Edge, Apple Safari and Opera.
NETWORK

A network is defined as a group of two or more computer systems linked together. There
are many types of computer networks, including the following:

• Local-area networks (LANs): The computers are geographically close together

(that is, in the same building).
• Wide-area networks (WANs): The computers are farther apart and are
connected by telephone lines or radio waves.
• Campus-area networks (CANs): The computers are within a limited geographic
area, such as a campus or military base.
• Metropolitan-area networks MANs): A data network designed for a town or city.
• Home-area networks (HANs): A network contained within a user’s home that
connects a person’s digital devices.

NETWORK CHARACTERISTICS

In addition to these types, the following characteristics are also used to categorize different
types of networks:

• Topology : The geometric arrangement of a computer system. Common

topologies include a bus, star, and ring. See the Network topology diagrams in
the Quick Reference section of Webopedia.
• Protocol : The protocol defines a common set of rules and signals that computers
on the network use to communicate. One of the most popular protocols for LANs
is called Ethernet. Another popular LAN protocol for PCs is the IBM token-ring
network .
• Architecture : Networks can be broadly classified as using either a peer-to-
peer or client/server architecture.
Computers on a network are sometimes called nodes. Computers and devices that
allocate resources for a network are called servers.

Image: Network Topology diagram

(v.) To connect two or more computers together with the ability to communicate with each
other.

NETWORK TOPOLOGIES
Network topology describes how a network is arranged physically and logically. This
description includes how links and nodes are connected in relation to each other. There are
many varieties of network topologies including:

• Bus: Each computer and network device is connected to a single cable or

backbone.
• Star: Every host device is connected to one central host.
• Ring: Each network device connects to exactly two other network devices, which
forms a single continuous pathway for signals to move through each device, like a
ring.
• Mesh: Each network device is connected in a way where each device distributes
data amongst each other.
• Tree: Each computer device is connected like branches on a tree; it is a
combination of bus and star network topology.

PUBLIC VS. PRIVATE NETWORKS

There are two types of networks one can connect to. This includes private and public
networks. A public network is a type of network in which anyone who has access to and
through it can connect to the internet. A private network involves restrictions that are
established to promote a secured environment. Some things to note when it comes to
public and private networks include:

• Private networks require a password, most public networks do not

• Some public networks (like hotels or businesses) require a web login for
authentication
• Public networks (like at airports and cafes) should be used with caution and a
VPN

EXAMPLES OF NETWORK DEVICES

o Internet-enabled devices such as laptops, smartphones, gaming

consoles, printers, smart home devices
o Servers are pieces of computer hardware or software that provides
functionality for other programs or devices
o Firewalls monitor and filter incoming and outgoing network traffic
based on a business’s previously established security policies
o Bridges connect two LANs and controls data flow between them
o Switches learn which machine is connected to its port by using its IP
address
o Repeaters amplify received input signals to a higher frequency domain,
so it is reusable and scalable
o Hubs are physical layer networking devices used to connect multiple
devices in a network
o Modems are small boxes that connect your devices to the internet
using cables

o Routers are devices that forward data packets between computer

networks
o NICs, or network interface cards, provide computers with a dedicated,
full-time connection to a network

Benefits of a Network:
1. Information sharing –
Authorized users can use other computers on the network to access
and share information and data. This could include special group
projects, databases, etc.
2. Hardware sharing –
One device connected to a network, such as a printer or a scanner,
can be shared by many users.
3. Software sharing –
Instead of purchasing and installing a software program on each
computer, it can be installed on the server. All of the users can then
access the program from a single location.
4. Collaborative environment –
Users can work together on group projects by combining the power
and capabilities of diverse equipment.
Network Criteria:
A network must meet the following network criteria:
1. Performance –
It measured by transit time and response time [also depends on
users, medium, hardware, software.
2. Reliability –
It measured by the frequency of failure.
3. Security –
It protecting data from unauthorized access.
Risks of network computing:
The security of a computer network is challenged every day by:
• Equipment malfunctions
• System failures
• Computer hackers
• Virus attacks
E-mail System

E-mail system comprises of the following three components:

• Mailer
• Mail Server
• Mailbox
Mailer
It is also called mail program, mail application or mail client. It allows us to manage, read and
compose e-mail.
Mail Server
The function of mail server is to receive, store and deliver the email. It is must for mail servers
to be Running all the time because if it crashes or is down, email can be lost.
Mailboxes
Mailbox is generally a folder that contains emails and information about them.

Working of E-mail

Email working follows the client server approach. In this client is the mailer i.e. the mail
application or mail program and server is a device that manages emails.
Following example will take you through the basic steps involved in sending and receiving
emails and will give you a better understanding of working of email system:
• Suppose person A wants to send an email message to person B.
• Person A composes the messages using a mailer program i.e. mail client and
then select Send option.
• The message is routed to Simple Mail Transfer Protocol to person B’s mail
server.
• The mail server stores the email message on disk in an area designated for
person B.
The disk space area on mail server is called mail spool.
• Now, suppose person B is running a POP client and knows how to communicate
with B’s mail server.
• It will periodically poll the POP server to check if any new email has arrived for
B.As in this case, person B has sent an email for person B, so email is forwarded
over the network to B’s PC. This is message is now stored on person B’s PC.
The following diagram gives pictorial representation of the steps discussed above:
The email refers to the electronic means of communication of sending and receiving messages
over the Internet. Email is the most common form of communication nowadays. An email has
significantly evolved over the past couple of years. There are now stronger sync and
messaging features along with stronger security and spam-related features.

Components of an Email:

Sender: The sender creates an email in which he records the information that needs to be
transferred to the receiver.

Receiver: The receiver gets the information sent by the sender via email.

Email address: An email address is just like a house address where the communication arrives
for the sender and receiver and they communicate with each other.

Mailer: The mailer program contains allows the ability to read, write, manage and delete the
emails like Gmail, Outlook, etc.

Mail Server: The mail server is responsible for sending, receiving, managing, and recording all
the data proceeded by their respective mail programs and then processing them to their
respective users.

SMTP: SMTP stands for Simple mail transfer protocol. SMTP basically uses the internet
network connection to send and receive email messages over the Internet.

Protocols of Email:

Emails basically use two types of standard protocols for communication over the Internet.
They are:-
POP: POP stands for post office protocol for email. Similar to a post office, our approach is
just to drop the email over the service mail provider and then leave it for services to handle
the transfer of messages. We can be even disconnected from the Internet after sending the
email via POP. Also, there is no requirement of leaving a copy of the email over the web server
as it uses very little memory. POP allows using concentrate all the emails from different email
addresses to accumulate on a single mail program. Although, there are some disadvantages
of POP protocol like the communication medium is unidirectional, i.e it will transfer
information from sender to receiver but not vice versa.

IMAP: IMAP stands for Internet message access protocol. IMAP has some special advantages
over POP like it supports bidirectional communication over email and there is no need to store
conversations on servers as they are already well-maintained in a database. It has some
advanced features like it tells the sender that the receiver has read the email sent by him.
Email is a service which allows us to send the message in electronic mode over the internet.
It offers an efficient, inexpensive and real time mean of distributing information among
people.
E-Mail Address
Each user of email is assigned a unique name for his email account. This name is known as E-
mail address. Different users can send and receive messages according to the e-mail address.
E-mail is generally of the form username@domainname. For example,
webmaster@tutorialspoint.com is an e-mail address where webmaster is username and
tutorialspoint.com is domain name.
• The username and the domain name are separated by @ (at) symbol.
• E-mail addresses are not case sensitive.
• Spaces are not allowed in e-mail address.
E-mail Message Components
E-mail message comprises of different components: E-mail Header, Greeting, Text, and
Signature. These components are described in the following diagram:
E-mail Header
The first five lines of an E-mail message is called E-mail header. The header part comprises of
following fields:
• From
• Date
• To
• Subject
• CC
• BCC
From
The From field indicates the sender’s address i.e. who sent the e-mail.
Date
The Date field indicates the date when the e-mail was sent.
To
The To field indicates the recipient’s address i.e. to whom the e-mail is sent.
Subject
The Subject field indicates the purpose of e-mail. It should be precise and to the point.
CC
CC stands for Carbon copy. It includes those recipient addresses whom we want to keep
informed but not exactly the intended recipient.
BCC
BCC stands for Black Carbon Copy. It is used when we do not want one or more of the
recipients to know that someone else was copied on the message.
Greeting
Greeting is the opening of the actual message. Eg. Hi Sir or Hi Guys etc.
Text
It represents the actual content of the message.
Signature
This is the final part of an e-mail message. It includes Name of Sender, Address, and Contact
Number.
Advantages
E-mail has proved to be powerful and reliable medium of communication. Here are the
benefits of E-mail:
• Reliable
• Convenience
• Speed
• Inexpensive
• Printable
• Global
• Generality
Reliable
Many of the mail systems notify the sender if e-mail message was undeliverable.
Convenience
There is no requirement of stationery and stamps. One does not have to go to post office. But
all these things are not required for sending or receiving an mail.
Speed
E-mail is very fast. However, the speed also depends upon the underlying network.
Inexpensive
The cost of sending e-mail is very low.
Printable
It is easy to obtain a hardcopy of an e-mail. Also an electronic copy of an e-mail can also be
saved for records.
Global
E-mail can be sent and received by a person sitting across the globe.
Generality
It is also possible to send graphics, programs and sounds with an e-mail.
Disadvantages
Apart from several benefits of E-mail, there also exists some disadvantages as discussed
below:
• Forgery
• Overload
• Misdirection
• Junk
• No response
Forgery
E-mail doesn’t prevent from forgery, that is, someone impersonating the sender, since sender
is usually not authenticated in any way.
Overload
Convenience of E-mail may result in a flood of mail.
Misdirection
It is possible that you may send e-mail to an unintended recipient.
Junk
Junk emails are undesirable and inappropriate emails. Junk emails are sometimes referred to
as spam.
No Response
It may be frustrating when the recipient does not read the e-mail and respond on a regular
basis.

nternet Relay Chat (IRC) is an Internet application that was developed by Jakko
Oikarinen in Finland. Chat is the most convenient immediate way to communicate with
others via Internet. There are a number of topics called “channels” through which you can
chat with many people all over the world. After joining channel, you can see what other
people on this channel type on their keyboards. In that situation, everyone on this channel
can see whatever you type on your keyboard. You can also hold individual conversations
with someone. Channels get live on different servers around the world. Some servers have
only a few channels, while others have many of them.
Model used for IRC :
IRC follows client-server model. It means that both client and server software are required
in order to use it. Many IT (Information Technology) clients are available for different
kinds of computers, so whether you have a PC, Macintosh, or UNIX work-section, you will
be able to use IRC.
Chatting on IRC :
IRC client connects/communicates with IRC server on Internet. First, you have to log on to
the server using a client and then pick the channel on which you want to chat. They are
sent to your server when you type words on your keyboard. Now your server is part of
global IRC server network. Your server sends your messages to other servers, which in
turn, sends your messages to people who are part of your channel.
They can then read and respond to your messages. Many websites use proprietary chat
software that does not use IRC protocol but enables you to chat when you are on site.
There is another kind of chat, called Instant Messaging. In this kind of chatting, you
communicate privately, one-to-one, with another person. You can create special lists so
that you are informed when your “buddies” come online, ready to chat, and they are
informed when you come online.
Working on IRC :
When you want to chat, first you have to make a connection to Internet and then start
your client software. After that, you need to log on to IRC server which is located on
Internet. There are many IRC servers are located all over the world. Those IRC servers are
connected together in network so that they can communicate with each other.
Servers are connected in spanning tree architecture. In this case, each server is connected
to several others, but these servers are not directly connected to one another. When you
connect to server, first you have to choose a specific channel to join and then choose a
user name to identify yourself when you at chat. Many channels are available that cover
different topics. Your message is sent from client software on your PC to IRC server to
which you are connected. Then message is sent from one server to other servers where all
users on this channel are logged on.
In this network, messages are transferred from one server to another server. Under a
spanning-tree server architecture, a message always takes the shortest route through
network to reach its final destination. Each server sends messages to client software of
their respected users who are connected to channel/network. Then people/users can read
and respond to your message on their computers.

Client Software for Chat :

CHAT TYPE SOFTWARE REQUIRED
Internet Relay Chat (IRC) Chat program such as mIRC or Ircle
Web-based chat Web browsers like Netscape or Internet Explorer
AOL (America Online)
Chat AOL access program for America online
Direct Chat Programs ICQ, AOL Instant Messenger, or other program
Conferencing program (CU-SeeMe, Netscape conference,
Online Conferencing Netmeeting)

Chat Servers : Communication servers permit you to give your information to large
number of users in environment that is just like Internet newsgroups. The most advanced
servers have recently started augmenting the text-based medium of conversation with
dynamic voice and video support. There are three major types of communication servers :
1. EFnet servers
2. UnderNet Servers
3. DALnet servers

Advantages of IRC:
1. It is decentralized.
2. It allows chat and file sharing.
3. Flexible and robust which allows real time discussion.
4. It has the concept of access levels for better privacy.
Disadvantages of IRC:
1. It consumes bandwidth.
2. Concern is there with flooding.
3. Fear of security incidents are there.
4. Concern with Cyberbullying.