Types of Browsers
1. Line mode browsers:
The initial browsers were line mode text browsers.
These browsers were simple and used to display text line by line.
They used to provide command line interface to the user on a less sophisticated computers and terminals.
These browsers provided fast access to websites as they displayed only the text part.
Example: Lynx is a line mode browser.
2. Graphical user interface based browsers:
These browsers run under graphic user interface systems such as Windows, Macintosh etc.
A graphical browser, in addition to text can handle images, audio, video and animation.
These browsers are very easy to use.
They have good display features.
3. Java enabled web browsers:
These browsers include a java runtime environment that support java programming language.
These browsers can dynamically load java applet from web server to web client.
These browsers are portable, extensible and secure.
The example of java enabled browser is - LOBO.
It is open source software written completely in java.
WWW is used for many applications today including banking, reservation, trading, e-commence and many such applications which require security and confidentiality of data.
However, HTTP was not a secure protocol.
Thus, a secure HTTP protocol was developed for applications that required secure communication channel over an unsecured network.
This is called HTTP secure and most of the contemporary browsers support this HTTPS protocol.
Thus, if you are browsing a secure website then you will find https:// at the beginning.
In case, you are browsing from a public computer then you must delete the contents of web cache, cookies and browsing history. All browsers provide simple way of doing this task.
A cookie is a small message sent by the web server to a your web client. This message is stored by the browser as a text file.
Cookies are merely text files that can be deleted at any time - they are not malicious nor are they programs.
Cookies cannot be used to spread viruses and they cannot take control of your hard drive.
However, they contain important information about the user, so they may be threat to the user’s privacy and anonymity on the internet.
The cookie contains information that provide to a website.
The basic purpose of cookie is to store information needed by a server at the user end only.
The cookie is used to send information back to the web server each time the browser requests a page from the server.
For example, a website may ask you to fill up a form with the information about your name and interests.
This information is packaged by the server into a cookie and sent to one’s web browser which stores it for later use.
The next time, one can go to the same website, the user browser will send the stored cookie to the web server along with the request for a web page.
This way, server will be able to remember you and send you only that information that you had desired earlier.
Steps for safe web browsing:
1. Do not click all the links without considering the risks of actions. Some web page addresses may be disguised and may be very close to address of a site the user want to visit but they may take the user toan unexpected site.
2. Use the latest versions of browsers and please do not configure them to have decreased security.
3. Do not login to a critical application if it does not have https://.
4. Please do not download or install plug-in from the unknown party such tendencies may put one’s computer to additional risk.
5. Do not visit unsolicited websites, those add to your computer vulnerabilities.
Millions of people across the globe are able to communicate and interact with each other through the internet.
All we need for this is an internet connection on any computing device like desktop, palmtop, laptop, mobile phone, etc.
Applications of the internet have covered almost every field – be it education, research, entertainment, communication, science, commerce, shopping, advertising and many more.
Network of networks:
The internet is possible because of the ability to interact and share information between the computers connected through a network.
The internet is often called the network of networks which enables us to interact and communicate with each other.
The internet, often referred to as the ‘Net’, consists of a complex network of computers connected by high-speed communication technologies like satellites, microwave devices, etc.
It allows easy and quick access to a huge amount of information/ resources stored at many different locations around the world.
The actual term “internet” was finally coined in 1995 by the FNC (Federal Networking Council, USA).
Functions of the Internet:
Functioning of the Internet is not controlled by any one particular organisation. It is managed by a group of voluntary organisations.
G These voluntary organisations have formed the Internet Society. They decide on the rules, known as protocols, for communication over the internet.
World Wide Web (WWW):
WWW is a hypermedia based software technology allowing consolidation of hypertext, graphics, audio, video and multimedia to provide information on almost each and every subject.
It is also known as W3.
WWW was started in 1989 at CERN (European Center for Nuclear Research).
The demand for interaction and communication led to the rapid growth in this area of communication.
URL (Uniform Resource Locator):
Every page has an address associated with it. This address is known as the URL.
URL stands for Uniform Resource Locator.
It tells us the location of the web page being displayed and other related information.
A unique location (address) of a web element which may be a website or a web page is required in the World Wide Web to view it in the browser.
This unique address of the web elements is referred to as a URL.
Components of URL:
The URL consists of four basic parts, namely - server type, hostname, folder name and the filename. Each one of these has a specific function.
It indicates the type of internet server (protocol) being accessed.c The server type is always followed by “://” and the host name.
The host name is the internet address of a remote computer on which the files reside.
The folder name indicates the name of the directory in which the files are located.
The filename specifies the name of the specific document to be displayed in the browser.
The filename itself consists of two pieces of information, the name of the file to be displayed and the file extension, which specifies the file type (.htm for HTML file, .txt for a text file, .bmp for a bitmap image, etc.)
1. http - Hyper Text Transfer Protocol is used to transfer the hypertext.
2. UDP- User Datagram Packet is used to transfer data between two computers.
3. TCP/IP - Transmission Control Protocol/ Internet Protocol.
4. ftp- File Transfer Protocol is used to transfer binary and text files over the internet
Accessing to the internet:
To activate internet services on any computer, it requires an internet connection from an Internet Service Provider.
Steps to get internet connection:
1. Dial-up connection:
The user can get connected to the internet by dialing the ISP’s number. This is useful if the network is either confined to small group of computers or for a single PC.
2. Leased lines:
G A dedicated line is laid specifically for the connection. This provides a fairly high speed, but it is expensive.
While leased line requires a separate telephone line, broadband can be delivered using an existing telephone line.
This is ideal for home and small businesses requiring high speed internet.
It provides good speed.
4. WiFi Broadband:
It is an wireless connection. For this the user need to have a Wi Fi card attached to the computer and a wireless modem.
5. Speed of the internet:
When we connect to the internet we must know its speed parameters.
The speed of the internet is measured in the number of bits transferred per unit time.
Generally, the speed of the internet is measured in kbps (kilo bits per second), but these days some organisations are providing high speed connections in mbps (mega bits per second).
Terms associated with internet:
With reference to internet, the number of bits transferred by a channel per unit time is the bandwidth.
Modem converts the digital signal from the computer into an analogue signal that can travel through the telephone line.
This analogue signal is again converted backto digital form by the modem at the destination end.
Some PCs have internal modems (built-in within the motherboard) while in some there might be a need to have an external modem to have an internet connection. Router:
It is attached to a computer to access the internet.
It is used for connecting two different networks.