Basic of Internet : class 9th notes

Introduction

Internet is a ‘global network of computer networks’. It comprises of millions of computing devices that carry and transfer volumes of information from one device to the other. Desktop computers, mainframes, GPS units, cell phones, car alarms, video game consoles, are connected to the Net. 

World wide web

The World Wide Web (WWW) is an internet based service, which uses common set of rules known as Protocols, to distribute documents across the Internet in a standard way. The World Wide Web was invented by Tim Berners-Lee in 1989, in 1995 the first connection was established over what is today known as the Internet. In April 1993, this technology was available for anyone to use on a royalty-free basis.

Difference between Internet and WWW

The Internet is known as “interconnection of computer networks” and the World Wide Web is a massive collection of digital pages to access information over the Internet.

Search Engines

• Web crawling :- Web search engines work by storing information about many web pages. These pages are retrieved by the program known as Web crawler – which follows every link on the site. Web crawler may also be called a Web spider.
• Indexing :- Indexing also known as web indexing, it stores data to facilitate fast and accurate information retrieval.
• Searching :- A web search query fetches the result from the web search engine entered by the user to meet his information needs.

Web Servers

A server is a computer that provides data to other computers. It helps to deliver web content that can be accessed through the Internet. The most common use of web servers is to host websites, and other uses such as gaming, data storage or running business applications.

The primary job of a web server is to deliver web pages to clients. The communication between the client node and server node takes place using the Hypertext Transfer Protocol (HTTP). The delivered web pages include images, style sheets and scripts in addition to text content.

Various services provided by the Web server are:

• Resource Sharing :- Web Server has the capability to store unlimited information such as Google Drives, Cloud computing etc, where the data can be stored is shared by the other users at the same time like hard disk can be shared on physical network as LAN.
• Data Sharing :- With the help of web servers one can easily access the information from anywhere, where there is an Internet connection using Google docs such as Documents, Excel sheets, Drawings, Powerpoint presentations etc.
• Backup and Recovery :- As all the data now a days is stored on web servers, backing it up and restoring the same is relatively much easier than storing the same on a physical device.

Types of Servers

• Mail Server :- Mail Servers provides a centrally-located pool of disk space for network users to store and share various documents in the form of emails.
• Application Server :- An application server acts as a set of components accessible to the software developer through an API defined by the platform itself. For Web applications, these components are usually performed in the same running environment as its web server(s), and their main job is to support the construction of dynamic pages.
• File Transfer Protocol (FTP) Server :- FTP uses separate control and data connections between the client and the server. For secure transmission username and password must be encrypted using FTP and SSL. 
• Domain Name System (DNS) Server :- A name server is a computer server that hosts a network service for providing responses to queries. The primary function of these DNS servers is the translation (resolution) of humanmemorable domain names and hostnames into the corresponding numeric Internet Protocol (IP) addresses.

Web Site

The collection of web pages on the World Wide Web that is accessed by its own Internet address is called a Web site. Each Web site contains a home page and contains other additional pages and it owned and updated by an individual, company, or an organization. 

Components of Website

• Contents of a Web Page :- A webpage of a website must contain the basic elements such as Page title, URL, file name, header, footer, navigation, web page content.
• Heading of the site: :- Headings in a website play a crucial role as they not only present a clear structure of the web page to the audience and help the search engines to retrieve the required information.
• Effective Colour Contrast :- Website visitors must not have any difficulty in reading a web page because at the times when we pick a colour scheme for our website we forget that there are people with poor vision and colour deficiencies. 

Steps to build a Website

• Step 1: Purchase free or paid Hosting.
• Step 2: Purchase free or paid Domain Name.
• Step 3: Plan Your Website or Select the type of site.
• Step 4: Build Your Website Page by Page.
• Step 5: Publish Your Website.
• Step 6: Promote Your Website.
• Step 7: Maintain Your Website regularly.

Software used to Create Website

• CoffeeCup Free HTML Editor
• Notepad++
• PageBreeze
• Firebug
• Brackets
• GIMP
• And Visual studio code, Which developed by Microsoft and it is free for individual or Student.

Webpage

A Web page also known as Electronic Page, is a part of the World Wide Web.

What makes a web page works?

• The server receives the request for a page sent by your browser.
• The browser connects to the server through an IP Address.
• In return, the server sends back the requested page.

Difference between Webpage and Website

A web page is one single page of information, while a website is made up of a number of different web pages connected by links known as Hyperlinks.

Web Browser

A browser is a software that lets you view web pages, graphics and the online content, it designed to convert HTML and XML into readable documents.

Eg :- Google Chrome, Firefox, Microsoft edge, Safari etc.

Tool Bar

• Back button :- Helps to open the previously opened website.
• Back history :- Helps to bring up a list of the sites visited. 
• Forward button :- This button will only be available once you have used the Back button at least once. It helps to take you to the page you just left when you clicked on the Back button.
• Forward history :- That brings up a list of the sites you have visited and then used the Back button to return.
• Stop :- Helps to stop the current download.
• Refresh :- Gives the most recent version of the page that we are on.
• Home :- Helps you to instantly get back home page (first page). 
• Search :- Helps to retrieve the specified files using web search engine.
• Favourites :- Helps to open up the most frequently visited sites. 
• History :- Helps you to see where you have been on the Internet. 

Blogs

A blog is a modern online writer’s column. A blog is a web site like any other, but it is intended to offer personal opinions of people on their hobbies, interests, commentaries, photo blogs, etc. It can also be used for commercial purposes.

There are two ways of starting your own blog:

• Free blog hosting :- You do not need a server to start your own blog. There are plenty of free, open source blogging software you can install. For example WordPress and blogger.

• Paid blogging :- Another way is when a company provides you a limited amount of space or a column on their website and the blogger has to pay for the same till the time he is using the available space. 

Types of blogs

• Personal blogs
• News and views
• Company blogs
• Micro blogs

Bloggers

A person who writes a blog is simply known as a blogger.

A good blogger should keep a few things in mind:

• Write unique but meaningful content.
• Try keeping the language simple and concise and incorporate some surprise elements.
• Remember to BE ORIGINAL.
• Don’t make it boring.
• Knowing your topic is good but not enough.
• Write crisp, short, active sentences with powerful verbs. And so on……

Advantages of Blogging:

• We can work on blog anytime and anywhere in the world, whenever you think of something that is relevant to your blog.
• You are flexible and can choose to write about anything in the world.
• Very quick and easy to set up, do not need much technical knowledge.
• Easy and quick to update or add new posts.

Disadvantages of Blogging:

• You need to be patient because you don’t start earning in a single day.
• Blogging is time-consuming.
• You need to be very active as a blogger so that people can read your blog posts.

URL

URL’s, or ‘uniform resource locators’, are the web browser addresses of internet pages and files. It specifies the address of a file and every file on the Internet has a unique address. Web software, such as your browser, use the URL to retrieve a file from the computer on which it resides.

Format of a URL:

Protocol://site address/path/filename

• Protocol which ends with a ‘//:’
• Host computer which ends with web extensions such as .com, .org etc.
• Filename or page name which displays the related information.

Eg:- https://www.jrworld.in/2021/04/basic-of-internet-class-9th-notes.html

Types of URL

• Absolute URL :- It contains entire address from the protocol (HTTPS) to the domain name (www.example.com) and includes the location within your website in your folder (/foldernameA or /foldernameB) names within the URL. Eg. <a href = http://www.example.com/xyz.html>
• Relative URL :- It does not use the full web address and only contains the location following the domain. Eg. <a href = "/xyz.html">

Protocols

A protocol is a set of rules that governs the communication between computers on a network. They exist at several levels in a telecommunication connection.

Types of Protocols

• TCP/IP :- TCP(Transmission Control Protocol) manages the assembling of a message or file divided into smaller packets that are transmitted over the Internet and received by a TCP that reassembles the packets into the original message on the destination computer. And IP (Internet Protocol), handles the address part of each packet so that it gets to the right destination.
• HTTP :- HyperText Transfer Protocol, is a set of standards that allows users of the World Wide Web to exchange information found on web pages on internet. It defines how messages are formatted and transmitted, and what actions Web servers and browsers should take in response to various commands. 
• FTP :- File Transfer Protocol is a standard protocol used on network to transfer the files from one host computer to another host computer using a TCP based network, such as the Internet.