- The Internet is a global network of billions of computers and other electronic devices. With the Internet, it’s possible to access almost any information, communicate with anyone else in the world, and do much more.
- It’s important to realize that the Internet is a global network of physical cables, which can include copper telephone wires, TV cables, and fiber optic cables. Even wireless connections like Wi-Fi and 3G/4G rely on these physical cables to access the Internet.
- On visiting a website, the computer sends a request over these wires to a server. A server is where websites are stored, and it works a lot like computer’s hard drive. Once the request arrives, the server retrieves the website and sends the correct data back to computer.
- The World Wide Web—usually called the Webfor short—is a collection of different websitesyou can access through the Internet. A website is made up of related text, images, and other resources. Websites can resemble other forms of media—like newspaper articles or television programs—or they can be interactive in a way that’s unique to computers.
- The purpose of a website can be almost anything: a news platform, an advertisement, an online library, a forum for sharing images, or an educational site.
- Web Browseris an application software that allows us to view and explore information on the web. In other words, a browseris a software program created as a simplified means to present and explore content on the World Wide Web. These pieces of content, including pictures, videos, and web pages, are connected using hyperlinks and classified with Uniform Recourse Identifiers (URLs).
- There have been many different web browsers that have come and gone over the years. The first, named WorldWideWeb (later changed to Nexus), was invented by Tim Berners-Leein 1990. However, the first graphical browser and widely used browser that help bring popularity to the Internet was NCSA Mosaic.
- List of current Internet browsers
|Netscape Navigator||Netscape Communications Corp.|
|Sea Monkey||Mozilla Foundation|
- 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.
- 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, firstname.lastname@example.org 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)
- 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.
- The first five lines of an E-mail message is called E-mail header. The header part comprises of following fields:
The From field indicates the sender’s address i.e. who sent the e-mail.
The Date field indicates the date when the e-mail was sent.
The To field indicates the recipient’s address i.e. to whom the e-mail is sent.
The Subject field indicates the purpose of e-mail. It should be precise and to the point.
CC stands for Carbon copy. It includes those recipient addresses whom we want to keep informed but not exactly the intended recipient.
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 is the opening of the actual message. Eg. Hi Sir or Hi Guys etc.
It represents the actual content of the message.
This is the final part of an e-mail message. It includes Name of Sender, Address, and Contact Number.
E-mail system comprises of the following three components:
- Mail Server
It is also called mail program, mail application or mail client. It allows us to manage, read and compose e-mail.
The function of mail server is to receive, store and deliver the email. It is must for mail servers to be sunning all the time because if it crashes or is down, email can be lost.
Mailbox is generally a folder that contains emails and information about them.
E-mail Protocols are set of rules that help the client to properly transmit the information to or from the mail server. Here in this tutorial, we will discuss various protocols such as SMTP, POP, and IMAP.
SMTP stands for Simple Mail Transfer Protocol. It was first proposed in 1982. It is a standard protocol used for sending e-mail efficiently and reliably over the internet.
- SMTP is application level protocol.
- SMTP is connection oriented protocol.
- SMTP is text based protocol.
- It handles exchange of messages between e-mail servers over TCP/IP network.
- Apart from transferring e-mail, SMPT also provides notification regarding incoming mail.
- When you send e-mail, your e-mail client sends it to your e-mail server which further contacts the recipient mail server using SMTP client.
- These SMTP commands specify the sender’s and receiver’s e-mail address, along with the message to be send.
- The exchange of commands between servers is carried out without intervention of any user.
- In case, message cannot be delivered, an error report is sent to the sender which makes SMTP a reliable protocol.
IMAP stands for Internet Mail Access Protocol. It was first proposed in 1986. There exist five versions of IMAP as follows:
- Original IMAP
- IMAP allows the client program to manipulate the e-mail message on the server without downloading them on the local computer.
- The e-mail is hold and maintained by the remote server.
- It enables us to take any action such as downloading, delete the mail without reading the mail.It enables us to create, manipulate and delete remote message folders called mail boxes.
- IMAP enables the users to search the e-mails.
- It allows concurrent access to multiple mailboxes on multiple mail servers.
POP stands for Post Office Protocol. It is generally used to support a single client. There are several versions of POP but the POP 3 is the current standard.
- POP is an application layer internet standard protocol.
- Since POP supports offline access to the messages, thus requires less internet usage time.
- POP does not allow search facility.
- In order to access the messaged, it is necessary to download them.
- It allows only one mailbox to be created on server.
- It is not suitable for accessing non mail data.
- POP commands are generally abbreviated into codes of three or four letters. Eg. STAT.
- Comparison between POP and IMAP
|1||Generally used to support single client.||Designed to handle multiple clients.|
|2||Messages are accessed offline.||Messages are accessed online although it also supports offline mode.|
|3||POP does not allow search facility.||It offers ability to search emails.|
|4||All the messages have to be downloaded.||It allows selective transfer of messages to the client.|
|5||Only one mailbox can be created on the server.||Multiple mailboxes can be created on the server.|
|6||Not suitable for accessing non-mail data.||Suitable for accessing non-mail data i.e. attachment.|
|7||POP commands are generally abbreviated into codes of three or four letters. Eg. STAT.||IMAP commands are not abbreviated, they are full. Eg. STATUS.|
|8||It requires minimum use of server resources.||Clients are totally dependent on server.|
|9||Mails once downloaded cannot be accessed from some other location.||Allows mails to be accessed from multiple locations.|
|10||The e-mails are not downloaded automatically.||Users can view the headings and sender of e-mails and then decide to download.|
|10||POP requires less internet usage time.||IMAP requires more internet usage time.|
- Search Engine and Search Tools
Search Engine refers to a huge database of internet resources such as web pages, newsgroups, programs, images etc. It helps to locate information on World Wide Web.
User can search for any information by passing query in form of keywords or phrase. It then searches for relevant information in its database and return to the user.
Search Engine Components
Generally there are three basic components of a search engine as listed below:
- Web Crawler
- Search Interfaces
It is also known as spider or bots. It is a software component that traverses the web to gather information.
All the information on the web is stored in database. It consists of huge web resources.
This component is an interface between user and the database. It helps the user to search through the database.
Search Engine Working
Web crawler, database and the search interface are the major component of a search engine that actually makes search engine to work. Search engines make use of Boolean expression AND, OR, NOT to restrict and widen the results of a search. Following are the steps that are performed by the search engine:
- The search engine looks for the keyword in the index for predefined database instead of going directly to the web to search for the keyword.
- It then uses software to search for the information in the database. This software component is known as web crawler.
- Once web crawler finds the pages, the search engine then shows the relevant web pages as a result. These retrieved web pages generally include title of page, size of text portion, first several sentences etc.
These search criteria may vary from one search engine to the other. The retrieved information is ranked according to various factors such as frequency of keywords, relevancy of information, links etc.
- User can click on any of the search results to open it.
Search Engine Processing
Indexing process comprises of the following three tasks:
- Text acquisition
- Text transformation
- Index creation
It identifies and stores documents for indexing.
It transforms document into index terms or features.
It takes index terms created by text transformations and create data structures to support fast searching.
Query process comprises of the following three tasks:
- User interaction
It supporst creation and refinement of user query and displays the results.
It uses query and indexes to create ranked list of documents.
It monitors and measures the effectiveness and efficiency. It is done offline.
Following are the several search engines available today:
|It was originally called BackRub. It is the most popular search engine globally.|
|Bing||It was launched in 2009 by Microsoft. It is the latest web-based search engine that also delivers Yahoo’s results.|
|Ask||It was launched in 1996 and was originally known as Ask Jeeves. It includes support for match, dictionary, and conversation question.|
|AltaVista||It was launched by Digital Equipment Corporation in 1995. Since 2003, it is powered by Yahoo technology.|
|AOL.Search||It is powered by Google.|
|LYCOS||It is top 5 internet portal and 13th largest online property according to Media Matrix.|
|Alexa||It is subsidiary of Amazon and used for providing website traffic information.|
There are three basic types of search tools that most people use to find what they are looking for on the Web.
- Search Engines
- Subject Directories
- Meta Search Tools
None of these search tools allow to search the entire Web; that would be an almost impossible task. However, one can use these Web search tools to scour different parts of the Web, obtain different types of information, and broaden the Web search horizons.
Search the Web with Search Engines
Search engines are large, spider(software programs) created databases of web pages that help searchers find specific information on any given subject. When anyone type in a keyword or phrase and the search engine retrieves pages that correspond to the search query.
Search results gathered from these search engines are not always relevant to the keywords entered since these engines are not intuitive and cannot infer dynamically what it is, one might be searching for (although results are getting better all the time). This is why it’s important to learn how to search as efficiently as possible using such techniques as Boolean search, or basic Google search techniques.
Interpretation of relevancy is different in each search engine. Many search engineshave included categories to direct users to more relevant sites based on these particular topics.
Search the Web with Subject Directories
Subject directories, in general, are smaller and selective that search engines. They use categories to focus the search, and their sites are arranged by categories, not just by keywords. Subject directories are handy for broad searches, as well as finding specific websites. Most subject directories’ main purpose is to be informational, rather than commercial. A good example of a search directory is Yahoo, a combination search engine/search directory/search portal, or one of the original search directories, Open Directory or DMOZ for short.
Search the Web with Metasearch Engines
Metasearch engines get their search results from several search engines. Users will receive the best hits to their keywords from each search engine. Metasearch tools are a good place to start for very broad results but do not (usually) give the same quality results as using each search engine and directory.
- IT applications- E-Cards, E-Shopping, E-Commerce
An electronic card (e-card) is a special occasion, greeting or post card created and customized within a website and sent through the Internet to the recipient. Customizations may include a wide variety of backgrounds and text fonts including some as cursive writing, graphic images, cartoon-style animations (proprietary to Adobe), video and sometimes even music.
This term is also known as ecard, icard, i-card, digital postcard, cyber greeting card or digital greeting card.
Virtual cards were first started by Judith Donath at MIT Media Lab in 1994 and were created by the website called The Electronic Postcard.
Virtual card recipients are often sent an email with a link to a website where the card was created. Then the card may be viewed, played, copied, printed, etc. Such websites invariably include banner ads and others selling a variety of products. Some websites use virtual cards to market and draw attention to their other products and services, which may be their main product or service. The recipient is offered the opportunity to send their own customized cards to friends, family, etc. using their desktop machines, mobile devices and phones.
Advantages of virtual cards include the ease of sending them to many recipients, being environmentally friendly compared to paper/hard copy cards and the versatile and highly customizable content.
When you buy a product or a service over the internet, instead of going to a traditional brick-and-mortar store, it is called online shopping. Globally, an increasing number of people are buying over the Internet because it is more convenient.
starting with groceries and greeting cards to cell phones and ringtones for the cell phones, everything can be purchased online. While most people still find it convenient to buy their groceries from the neighbourhood shop, many people are purchasing rail and air tickets over the Internet. In addition, people and corporates as well, are also purchasing a variety of services online — such as a broking service or job search service.
Online shopping became popular during the Internet boom in 1999-2000. Amazon.com, the online bookstore founded by Jeff Bezos, created history by becoming the first bookstore with a presence only on the Internet. Following the success of Amazon, many bookstores with a physical presence also created an online presence on the Internet. Later, portals such as Yahoo.com and MSN.com also started online shopping channels where people could buy more than just books. Closer home, portals such as Indiatimes.com and Rediff.com came up with similar options for the Indian consumer.
Advantages of shopping online
It is convenient, faster and sometimes also cheaper. For instance, rather than standing in a long queue and waiting for your turn to purchase a ticket, people are finding it simpler to log on to a website and buy it. In some instances, one may have to pay a premium for an online purchase but it is still preferred because the convenience factor is higher.
Although online players in India are coming up with innovative ways to make payments, credit cards are still the most widely accepted form of making payments over the Internet.
Security of payment
Security standards for online shopping are now well-established, so it is safe to pay online using your credit card. Your credit card details and other information are encrypted and sent over a secure layer over the Internet. Although no system is completely fraud-proof, the large number of people going online bears testimony to the acceptance and safety of online shopping.
Now a days, with more advanced technologies many things are about to come. Cheap internet and Mobile with widely avilable services as well as incresing Mobile apps, giving huge boost to online shopping. With Digital India Scheme and technology development, online shopping has been spread very fast in India.
E-commerce is a transaction of buying or selling online. Electronic commerce draws on technologies such as mobile commerce, electronic funds transfer, supply chain management, Internet marketing, online transaction processing, electronic data interchange (EDI), inventory management systems, and automated data collection systems.
Examples of Ecommerce
· Online Shopping
Buying and selling goods on the Internet is one of the most popular examples of ecommerce. Sellers create storefronts that are the online equivalents of retail outlets. Buyers browse and purchase products with mouse clicks. Though Amazon.com is not the pioneer of online shopping, it is arguably the most famous online shopping destination.
· Electronic Payments
When you are buying goods online, there needs to be a mechanism to pay online too. That is where payment processors and payment gateways come into the picture.
Electronic payments reduce the inefficiency associated with writing and mailing checks. It also does away with many of the safety issues that arise due to payment made in currency notes.
· Online Auctions
When you think online auction, you think eBay. Physical auctions predate online auctions, but the Internet made auctions accessible to a large number of buyers and sellers. Online auctions are an efficient mechanism for price discovery. Many buyers find the auction shopping mechanism much interesting than regular storefront shopping.
· Internet Banking
Today it is possible for you to perform the entire gamut of banking operations without visiting a physical bank branch. Interfacing of websites with bank accounts, and by extension credit cards, was the biggest driver of ecommerce.
· Online Ticketing
Air tickets, movie tickets, train tickets, play tickets, tickets to sporting events, and just about any kind of tickets can be booked online. Online ticketing does away with the need to queue up at ticket counters.
Types of Ecommerce
Ecommerce can be classified based on the type of participants in the transaction:
· Business to Business (B2B)
B2B ecommerce transactions are those where both the transacting parties are businesses, e.g., manufacturers, traders, retailers and the like.
· Business to Consumer (B2C)
When businesses sell electronically to end-consumers, it is called B2C ecommerce.
· Consumer to Consumer (C2C)
Some of the earliest transactions in the global economic system involved barter — a type of C2C transaction. But C2C transactions were virtually non-existent in recent times until the advent of ecommerce. Auction sites are a good example of C2C ecommerce.
Benefits of Ecommerce
The primary benefits of ecommerce revolve around the fact that it eliminates limitations of time and geographical distance. In the process, ecommerce usually streamlines operations and lowers costs.
Specialized Forms of Ecommerce
On some platforms, ecommerce has shown the promise of explosive growth. Two such examples are:
· M Commerce
Mcommerce is short for “mobile commerce.” The rapid penetration of mobile devices with Internet access has opened new avenues of ecommerce for retailers.
· F Commerce
Fcommerce is short for “Facebook commerce.” The immense popularity of Facebook provides a captive audience to transact business.UKPCS Notes brings Prelims and Mains programs for UKPCS Prelims and UKPCS Mains Exam preparation. Various Programs initiated by UKPCS Notes are as follows:-
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