CHAPTER-5 :Services on Internet

The internet is a combination of many networks and a large number of database and other Services.

Most of the services can be accessed through a web browser, such as Netscape Navigator or Microsoft Internet Explorer or Google chrome.

First Services: Email

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E-mail is a method of sending messages, voice, video and graphics over digital communication such as internet anywhere in the world at a very cost-effective rate.

E-mail is a type of client and server application that provided a routed, stored messages services between any two email accounts.

There are two broad procedure available for email such as;

i) Subscribe to a public E-mail server, such as Hotmail, Gmail. etc.

ii) Email belonging to your business may be carrying someone else's advertisement.

iii) Your name might be used by someone else. It means that your mail is not safe.

iv) Your e-mail address does not identify you.

Advantage of Email

i) Speed: A message can be reached any part of the world in a fraction.

ii) Content: The message may consist of only a few lines of text of several hundred lines. Unlike the postal services, the message is not charged by weight. 

iii) Cost: E-mail is extremely is a cost-effective way to move information globally.

iv) Easy of use: It is easy to send an email than a letter through a normal postal system.

In the postal system, we have to write a letter, find an envelope, buy a stamp, and then find a mailbox to drop it.

v) Receiving Messages: The message is stored by our service provider automatically. It will deliver the message to us when we ask for it.

vi) Multiple copies: We can send the same message to multiple users without re-typing the message again and again.

Limitation of E-mail

i) Hardware Requirement: We have to be at a computer to read or print email.

ii) A Hasty Medium: Because e-mail is easy to use, it is also easy to send a message that you might later regret.

iii) Hard to Convey Emotion: Without the extra clues of voice, posture and expression, it is easy to misunderstand, what someone really means in the message.

iv) Email is Not Private: As the message is passed from one system to another, there are chances that someone might intercept or read your email.

Features of Email

Second Service: World Wide Web (WWW)

- The web is the most popular internet service next to email.

- It is an internet-based global information system. 

- It accesses a larger quantity and great variety of data than any other service on the internet.

- It makes available multimedia information from over 10 million computers around the world.

- The web offers text, audio, video and interactive multimedia information.

Evolution of the WWW

- The web is a huge collection of hypertext pages on the internet.

- Developed in Switzerland.

- To access the webserver we used client software called a browser programme.


The basic features of the web

i) Hypertext Information system: 

The idea behind hypertext is that instead of reading text in a rigid, linear structure (such as a book), you can skip easily from one point another.

You can get more information, go back, jump to another topic.

ii) Graphical and Easy to Navigate

One of the best features of the web is its ability to display both text and graphics in full colour on the same page.

iii) Cross- Plateform

Cross-platform means that you can access web information from any computer hardware running any OS (Operating system) using any type of display.

iv) The Web is distributed

The web is successful in providing so much information because that information is distributed globally across millions of websites.

You as a consumer of that information go to that site to view the information, when you are done you can easily navigate to some other information easily.

v) The Web is dynamic

The accessibility and information can be updated at any time. New information and news can be published all most immediately.

Element of Web

i) www browsers (web client)

ii) www servers

WWW Browsers (Web Clients)

- the web browser is a computer program

- used to view information or web pages on the internet and navigate the www.

- Browsers are sometimes called web clients.

- Different browsers may formate and display the same file differently

- depending on the capability of the software and Hardware default layout options for the browser itself.

WWW Servers

- A Web server is a program that runs on a website.

- responsible for making available the services of web pages to web browsers.

- The host manages the communication protocol and the related software require to create a website on the internet.

Types of Servers

There are different types of servers software that performs different types of services for different types of clients such as; HTTP

 HTTP performs services to send HTML document to the requested client software.

The other kind of server are FTP which copy the internet files to the web client computer.

i) Telnet

ii) FTP

Third Service: Telnet

- Telnet stands for telecommunication network.

- Telnet is a global and local area network protocol that allowing a user to log on to TCP/IP host to access other hosts on the network.

- The telnet service allows internet users to log in to another computer somewhere on the internet. This action is called "remote login".

- Telnet is basically a Terminal Emulation programme allowing users to access text-based services of another computer.

Fourth Service: FTP 

- FTP allows on internet user to move a file from one computer to another on the internet.

- Moving a file from a remote computer to your computer is known as downloading.

- The file one's own computer to a remote computer is known as uploading. 

FTP Servers

i) Anonymous servers

ii) Non-anonymous servers

Anonymous Servers

- Anonymous Servers is the most common use of FTP.

- Any internet website running anonymous Servers do not require authentication.

- You can only have to log in as anonymous and just enter your email address, even this is also optional.

Non-anonymous servers

- If a website is running on non-anonymous FTP servers then it does not allow any internet user to move a file before authentication.

Fifth Service: USENET

- It stands for user-network.

- It is an international, non-commercial network linking many thousands of Linux based websites.

- It is the world largest electronics discuss forum.

- Usenet provides a way for messages to be sent among connected computers across the entire internet.

- People from all over the world participate in the discussion on the thousands of topic in specific areas of interest on interest.

Component of Usenet

There are two main components of Usenet, these are ;

i) News servers

ii) News Reader

News Servers

A program or a computer which provide a new feed is called a new server. Followings are some of the news servers are ;

espnet.sportzone.com

msnews.microsoft.com

News Reader

It is a client software to read the uploaded article. 

News servers and News Reader communicate by using network news transfer protocol (NNTP) works on the top layer of TCP/IP protocol.

Sixth Service: Search Engines

- Search engines are the computer programs, which look through its database for information that matches your request.

- Since the internet is the vast collection of information, it is difficult to find specific information. You need a search browser.

- The search engine scans the internet for the words (keywords) or topic you are looking for.

- Examples are ;

 Google chrome

 Internet explorer

 Bings

Seventh Service: Internet Relay Chat (IRC)

- Chat is the most integrated way to communicate with others via the internet.

- There are no. of topics called channel for which you can chat with many people all over the world.

- When you join a channel you can see what other people on the channel type on their keyboard.

- IRC is a Client-Server application.

- Some IRC chat servers ;

  irc.blankended.com
  irc.magic.ca

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