INTERNET

World Wide Web (WWW):
The World Wide Web came into being in 1991, and the concept given by Tim Berners-Lee. The World Wide Web is a system of interlinked hypertext documents accessed via the Internet. Hypertext is one method of presenting information in which certain items are highlighted. By selecting the highlighted text, you can obtain more information on the same topic. Tim Berners-Lee introduces WWW to the public on August 6, 1991.
Internet is the global connection of the networks. It is used for the wide area network/global area network that connect computers, spread all over the world. It is the network of networks. Internet consists of inter connection of networks of various types. It is a public Network. Through internet we can share text data, audio, video data. Internet is govern by Internet society (ISOC) and no one owner of internet.
Notes:-
Intranet is the small network as compared to Internet. It is a private network. It in owned by any company or firms.
ARPAnet link was established between three locations i.e California, Los angels and standards research Institute in 1969. ARPAnet was divided into ARPAnet for the general public and MILNET for military,sites.
There are some of the major software components required to access the Internet:
Software for the Internet access is the Operating System. An Operating System must be installed properly on your system.
Internet Browser:- Browser is a software that allows the user to access and read information on the world wide web. Internet Explorer, Mozilla, Netscape Navigator are the best known browser.
Firewall:- Internet has many security problems like hacking, Trojan Horse, Virus etc. There are various tools top provide protection against unwanted access to your computer by anyone else. A firewall helps to keep your computer more secure.
TCP /IP protocol:- This is the group of protocols that define the Internet and communication method used by it. In order to be compatible to the Internet, the computer must have TCPlIP compatible software. The major advantage of Internet is information sharing.
Modem - connect computer with phone line
ISP - Internet service provider which connect us to internet and charges amount for its services. ISP has computers called servers which remains permanently connected to other computers on net. ISP provides us user name and password to connect to internet. At present it is VSNL (Videsh Sanchar Nigam Limited) which is dominating the Internet scene in India through its GIAS (Gateway Internet Access Service). The other service providers in India are MTNL (Mahanagar Telephone Nigam Limited), Mantraon-line, and Satyam online.
Internet was available for some time through ERNET and it was made available for commercial use by VSNL since August 1995. Presently VSNL operates in the following six metros. Le New Delhi, Chennai, Calcutta, Mumbai, Bangalore, Pune.
Note:- TCP /IP emerged in 1978. In 1980, first ISP came into existence. In 1989, first dial up ISP came into existence. TCP/IP originally designed for the UNIX operating system. Now available for every major operating system.
Web Browser:- To access the World Wide Web, you use what is called a Web browser. Browsers are sometimes also called Web clients, since they get information from a server. When you start a WWW browser or follow a hyperlink, the browser (acting like a client) sends a request to a site on the Internet. That site (acting like a server) returns a file which the browser then has to display.
Basic Features of Browsers :- Some important browser features are-
The Web browser should be able connect to various sites to access information on internet
Another feature of browser is to have a number of other commands readily available through menus, icons, and buttons.
Main feature of the browser is to search the information on the current page as well as search the WWW.
It also give the, facility to save t he web page on your computer system.
Web browser should be able to handle text, images of the World Wide Web, as well as the hyperlinks to digital video, or other types of information.
Most important feature of any browser is easy to use.
Web browsers interact not just with the Web, but also with your computer's operating system and with other programs, called plug-ins, that gives the browser enhanced features
Types Of Browser:- There are different type of browser available nowadays. These browser are:- Mosaic, Netscape navigator, Internet Explorer, mozila firefox, Safari, Opera, Google chrome etc
First Web Browser was Mosaic developed in 1993. Netscape Navigator was second browser developed in 1994 and Microsoft Introduced internet explorer as browser in 1995.
Exploring the Internet using Browser
To Start Internet ⇒ Double Click on Browser's Icon on your desktop.
Tool Bars of the browser:-
Back button:- Lets you return to pages you've viewed, beginning with the most recent. Right-click the Back button and select from a list of recently visited sites.
Forward. Lets you move forward through pages you've viewed using the Back button. Right-click the Forward button and select from a list of recently visited sites.
Stop:- Halts the process of downloading a Web page. Click this if you want to stop downloading a page for any reason.
Refresh:- Updates any Web page stored in your disk cache with the latest content. Refresh button gets the information directly from the server and Reload button gets information from your disk cache.
Home:- Returns you to your home page. You can designate any Web page as your home page.
Search:- Displays a choice of popular Internet search engines in the left pane. Your search results appear in the left pane. When you click a link, the page appears in the right pane, so you don't lose sight of your search results.
Favorites:- Displays a list of the sites you have marked. Click any item in the list to jump to it.
History:- Shows a list of Web sites you've visited.
Print:- Prints the page you're viewing. This is one way to save information from the Internet so that you don't have to reconnect to view it again You can even print the URL associated with each hyperlink, making it easy to navigate to the site later.
Edit:- Opens a file in the Microsoft Word, word processor that contains the HTML code for the page you're viewing so you can see and even edit it.
Hype text Transfer protocol (HTTP):- There are two main modes of transferring file over the World Wide Web, one is FTP (file transfer protocol) and other is HTTP (Hypertext Transfer Protocol) Which is the set of rules for transferring files (text, graphic images, sound, video, and other multimedia files) on the World Wide Web. HTTP is an application protocol that runs on top of the TCP/IP suite of protocols. Whereas, FTP is used to transfer bulk files.
Note:- HTTP protocol for communication between web browser and servers.
Facility on Internet:
E-Mail
Upload and download files
Chatting
Search Engine
Chatting:- Chatting known as instant messaging. In this type of communication participants type messages to other chat group' participants and receiver response instantly which they can read on the screen. Some sites also provide audio/video chat that may be performed with the help of web carn.
Upload and Download:- Copying file from the external sources to the computer is known as downloading and sending file or data from your computer to the external source is known as uploading.
Search Engine:- Search engine is a website that allows you to search desired information from a vast database of web pages on WWW. Any words found on the web pages visited by the search engine are stored in the search engine database.
Note:- Search Engine were introduced like LYCOS in1993, WEB CROWLERin 1994, Yahoo and ALTA
VISTA in 1995, GOOGLE in 1998. BINGintroduced by Microsoft as search Engine.
Plug-Ins and Helper programs:- Web browsers are limited in their capabilities as far as interpreting those documents which are not in HTMLformat. However, a browser can be extended in its capability by adding small applications programs. Such programs that run within the browser are known as plug-ins. A number of plug-ins are available from various vendors. Some such plug-ins are:
Media Player
Acrobat Reader
Shock Wave etc.
E-Mail (Electronic mail):- Email allow us to send and receive message. You can attach picture, video, sounds to your email messages. Email address can be obtained free or with cost from yahoo, indiatimes, hotmail, gmail etc. Note:- In 1971, email address format using @ was created to separate user id and domain name. Comptiserve became the first service provider to offer email facility to PC users in 1979.
Folders on Email page:-
INBOX :- Contains the received messages.
Sent/OUTBOX :- contains the messages you have sent to others.
Compose :- this link opens the page where you write the message for sending to others
Spam/Bulk :- Unwanted commercial messages.
Drafts :- messages you have created but not sent.
Trash :- the received messages those you have deleted.
E-Mail address format:-
fac.manav2010@gmail.com
fac.manav2010 ⇒ user name
gmail ⇒ host name
.com ⇒ types of domain
Uniform Resource Locator (URL) :- A URL is a formatted text string used by Web browsers, email clients and other software to identify a network resource on the Internet. network resources are files that can be plain Web pages, other text documents, graphics, or programs.
Format of URL:-
Address of website is of the following format:
"http://www.google.com"
http ⇒ hyper text transfer protocol
www ⇒ world wide web
Google ⇒ domain name
.com ⇒ types of domain.
Types of domain:- Various types of domain are used on internet to distinguish between the types of websites like:-
.com ⇒ commercial
.edu or ac ⇒ educational or academic
.mil ⇒ military
.net ⇒ belonging to networking or internet service provider company
.org ⇒ organizational
.gov ⇒ government
.info ⇒ informational sites
Email protection against Virus:-
There are some characteristics of e-mail messages and attachments that may indicate they are unsafe to open. Characteristics include:
e-mail from unknown sender;
e-mail from a known sender, but subject line does not make sense;
message attachment containing filename extension associated with viruses; and
message containing links to destinations unrecognizable to the user.
User will successfully avoid virus infection by applying knowledge of these e-mail characteristics and taking appropriate action when reading e-mail (i.e. open message or delete it).
Email Spoofing:- E-mail spoofing is e-mail activity in which the sender address and other parts of the e-mail heade rare altered to appear as tough the e-mail originated from a different source.
Spoofing is the creation of TCP / IP packets using somebody else's IP address. Routers use the "destination IP" address in order to forward packets through the Internet, but ignore the "source IP" address. That address is only used by the destination machine when it responds back to the source. A common misconception is that "IP spoofing" can be used to hide your IP address while surfing the Internet, chatting on-line, sending e-mail, and so forth.
Important Notes:-
E-mail is developed:- Ray Tomlinson introduces network e-mail in 1972. The first messaging system to send messages across a network to other users.
TCP is developed:- Vinton cerf and Robert Kahn design TCP during 1973.
First commercial network:- A commercial version of ARPANET known as Telenet is introduced in 1974 and considered by many to be the first Internet Service Provider (ISP).
Ethernet is conceived :- Bob Metcalfe develops Ethernet idea in 1973.
DNS is introduced:- Paul Mockapetris and Jon Postel introduce DNS in 1984.
HTML:- In 1990 Tim Berners-Lee develops HTML, which made a huge contribution to how we navigate and view the Internet today.
Some Popular term on INTERNET
Cookies:- A cookie is a small message sent by the web server to your web client. This message is stored by the browser as a text file. The basic purpose of cookies 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.
Internet Rela Chat IRC :- (IRC) is multi user chat network where people around the world can chat and talk in channels or in private. To use IRC you must install IRC client on your computer. Using this client, you can connect to an IRC server, which is connected to other IRC networks.
Social Networking:- A social network is a network of individuals which have some sort of interdependence on each other. This interdependence may be in the form of friendship, common causes and so on. A social networking service may be offered through a web site on the Internet. Some of the popular social networking services are-Orkut, Facebook, Twitter, Linkedln, MySpace, Friend Finder etc.
Blog:- Blog is a website where entries are written as information or news on a particular subjects. You can choose any subject for writing a blog like food, health or information about anything.
Apache :-The most common web server (or HTTP server) software on the Internet. Apache is an open-source application· originally created from a series of changes ("patches") made to a web server written at the National Center for Supercomputing Applications, the same place the Mosaic web browser was created.
Archie:- A tool (software) for finding files stored on anonymous FTP sites. You need to know the exact file name or a substring of it. By 1999 Archie had been almost completely replaced by web-based search engines
BITNET:- (Because It's Time NETwork (or Because It's There NETwork)) Anetwork of educational sites separate from the Internet, but e-mail is freely exchanged between BITNETand the Internet. Listservs®, a popular form of e-mail discussion groups, originated on BITNET. At its peak (the late 1980's and early 1990's) BITNETmachines were usually mainframes, often running IBM's MVS operating system. BITNET is probably the only international network that is shrinking.
Extranet:- An intranet that is accessible to computers that are not physically part of a company's own private network, but that is not accessible to the general public, for example to allow vendors and business partners to access a company web site. Often an intranet will make use of a Virtual Private Network. (VPN).