What is the internet and how it works?

What is the internet?

World Wide Web
The World Wide Web (www) is a system of interlinked hypertext documents accessed via the Internet. With a Web browser, one can view Web pages that may contain text, images, videos, and other multimedia and navigate between them using hyperlinks. Using concepts from earlier hypertext systems, the World Wide Web was begun in 1989 by English scientist Tim Berners-Lee, working at the European Organization for Nuclear Research (CERN) in Geneva, Switzerland.

In 1990, he proposed building a "web of nodes" storing "hypertext pages" viewed by "browsers" on a network, and released that web in 1992. Connected by the existing Internet, other websites were created, around the world, adding international standards for domain names & the HTML language. Since then, Berners-Lee has played an active role in guiding the development of Web standards, and in recent years has advocated his vision of a Semantic Web.

The World Wide Web enabled the spread of information over the Internet through an easy-to-use and flexible format. It thus played an important role in popularising use of the Internet, to the extent that the World Wide Web has become a synonym for Internet, with the two being conflated in popular use.

Brief history of the internet

Before there was the public internet there was the internet's forerunner ARPAnet or Advanced Research Projects Agency Networks. ARPAnet was funded by the United States military after the cold war with the aim of having a military command and control center that could withstand nuclear attack. The point was to distribute information between geographically dispersed computers. ARPAnet created the TCP/IP communications standard, which defines data transfer on the Internet today. The ARPAnet opened in 1969 and was quickly usurped by civilian computer nerds who had now found a way to share the few great computers that existed at that time.

Father of the Internet Tim Berners-Lee

Tim Berners-Lee was the man leading the development of the World Wide Web (with help of course), the defining of HTML (hypertext markup language) used to create web pages, HTTP (HyperText Transfer Protocol) and URLs (Universal Resource Locators). All of those developments took place between 1989 and 1991.
Tim Berners-Lee was born in London, England and graduated in Physics from Oxford University in 1976. He is currently the Director of the World Wide Web Consortium, the group that sets technical standards for the Web.
Besides Tim Berners-Lee, Vinton Cerf is also named as an internet daddy. Ten years out of high school, Vinton Cerf begun co-designing and co-developing the protocols and structure of what became the Internet.

HTML

Vannevar Bush first proposed the basics of hypertext in 1945. Tim Berners-Lee invented the World Wide Web, HTML (hypertext markup language), HTTP (HyperText Transfer Protocol) and URLs (Universal Resource Locators) in 1990. Tim Berners-Lee was the primary author of html, assisted by his colleagues at CERN, an international scientific organization based in Geneva, Switzerland.

Email

Computer engineer, Ray Tomlinson invented internet based email in late 1971.

How it works?

Viewing a Web page on the World Wide Web normally begins either by typing the URL of the page into a Web browser, or by following a hyperlink to that page or resource. The Web browser then initiates a series of communication messages, behind the scenes, in order to fetch and display it. First, the server-name portion of the URL is resolved into an IP address using the global, distributed Internet database known as the domain name system, or DNS. This IP address is necessary to contact and send data packets to the Web server.

The browser then requests the resource by sending an HTTP request to the Web server at that particular address. In the case of a typical Web page, the HTML text of the page is requested first and parsed immediately by the Web browser, which will then make additional requests for images and any other files that form a part of the page. Statistics measuring a website's popularity are usually based on the number of 'page views' or associated server 'hits', or file requests, which take place.

Having received the required files from the Web server, the browser then renders the page onto the screen as specified by its HTML, CSS, and other Web languages. Any images and other resources are incorporated to produce the on-screen Web page that the user sees.

Most Web pages will themselves contain hyperlinks to other related pages and perhaps to downloads, source documents, definitions and other Web resources. Such a collection of useful, related resources, interconnected via hypertext links, is what was dubbed a "web" of information. Making it available on the Internet created what Tim Berners-Lee first called the WorldWideWeb. Statistics

According to a 2001 study, there were massively more than 550 billion documents on the Web, mostly in the invisible Web, or deep Web.[34] A 2002 survey of 2,024 million Web pages[35] determined that by far the most Web content was in English: 56.4%; next were pages in German (7.7%), French (5.6%), and Japanese (4.9%). A more recent study, which used Web searches in 75 different languages to sample the Web, determined that there were over 11.5 billion Web pages in the publicly indexable Web as of the end of January 2005.[36] As of June 2008, the indexable web contains at least 63 billion pages.[37] On July 25, 2008, Google software engineers Jesse Alpert and Nissan Hajaj announced that Google Search had discovered one trillion unique URLs.[38]

Over 100.1 million websites operated as of March 2008.[39] Of these 74% were commercial or other sites operating in the .com generic top-level domain.

Caching

If a user revisits a Web page after only a short interval, the page data may not need to be re-obtained from the source Web server. Almost all Web browsers cache recently-obtained data, usually on the local hard drive. HTTP requests sent by a browser will usually only ask for data that has changed since the last download. If the locally-cached data are still current, it will be reused.

Caching helps reduce the amount of Web traffic on the Internet. The decision about expiration is made independently for each downloaded file, whether image, stylesheet, JavaScript, HTML, or whatever other content the site may provide. Thus even on sites with highly dynamic content, many of the basic resources only need to be refreshed occasionally. Web site designers find it worthwhile to collate resources such as CSS data and JavaScript into a few site-wide files so that they can be cached efficiently. This helps reduce page download times and lowers demands on the Web server.

WWW prefix in Web addresses

The letters "www" are commonly found at the beginning of Web addresses because of the long-standing practice of naming Internet hosts (servers) according to the services they provide. So for example, the host name for a Web server is often "www"; for an FTP server, "ftp"; and for a USENET news server, "news" or "nntp" (after the news protocol NNTP). These host names appear as DNS subdomain names, as in "www.example.com".

This use of such prefixes is not required by any technical standard; indeed, the first Web server was at "nxoc01.cern.ch",[41] and even today many Web sites exist without a "www" prefix. The "www" prefix has no meaning in the way the main Web site is shown. The "www" prefix is simply one choice for a Web site's host name.

However, some website addresses require the www. prefix, and if typed without one, won't work; there are also some which must be typed without the prefix. Sites that do no have Host Headers properly setup are the cause of this. Some hosting companies do not setup a www or @ A record in the web server configuration and/or at the DNS server level.

W3C Develops Web Standards and Guidelines

The World Wide Web Consortium (W3C) is an international consortium where Member organizations, a full-time staff, and the public work together to develop Web standards. W3C's mission is: To lead the World Wide Web to its full potential by developing protocols and guidelines that ensure long-term growth for the Web.

W3C primarily pursues its mission through the creation of Web standards and guidelines. Since 1994, W3C has published more than 110 such standards, called W3C Recommendations. W3C also engages in education and outreach, develops software, and serves as an open forum for discussion about the Web. In order for the Web to reach its full potential, the most fundamental Web technologies must be compatible with one another and allow any hardware and software used to access the Web to work together. W3C refers to this goal as “Web interoperability.” By publishing open (non-proprietary) standards for Web languages and protocols, W3C seeks to avoid market fragmentation and thus Web fragmentation. Tim Berners-Lee and others created W3C as an industry consortium dedicated to building consensus around Web technologies. Mr. Berners-Lee, who invented the World Wide Web in 1989 while working at the European Organization for Nuclear Research (CERN), has served as the W3C Director since W3C was founded, in 1994.