World Wide Web
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World Wide Web
From Wikipedia, the free encyclopedia
CatalogueDefinition………………………………….P3-5The picture provides………………….P6History………………………………………P7-10The picture provides………………….P11Function……………………………………P12-16Linking………………………………………P17&P19-20The picture provides…………………P18
DefinitionThe World Wide Web (abbreviated as WWW or W3and commonly known as the Web) 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 via hyperlinks.
Using concepts from earlier hypertext systems, British engineer and computer scientist Sir Tim Berners-Lee, now Director of the World Wide Web Consortium (W3C), wrote a proposal in March 1989 for what would eventually become the World Wide Web.
"The World-Wide Web was developed to be a pool of human knowledge, and human culture, which would allow collaborators in remote sites to share their ideas and all aspects of a common project."
The Web's historic logo designed by Robert Cailliau
InventorCERN
CompanyTim Berners-Lee
AvailabilityWorldwide
The picture provides
History In the May 1970 issue of Popular Science
magazine Arthur C. Clarke was reported to have predicted that satellites would one day "bring the accumulated knowledge of the world to your fingertips" using a console that would combine the functionality of the Xerox, telephone, television and a small computer, allowing data transfer and video conferencing around the globe.
With help from Robert Cailliau, he published a more formal proposal (on November 12, 1990) to build a "Hypertext project" called "WorldWideWeb" (one word, also "W3") as a "web" of "hypertext documents" to be viewed by "browsers" using a client–server architecture.
While the read-only goal was met, accessible authorship of web content took longer to mature, with the wiki concept, blogs, Web 2.0 and RSS/Atom.
Berners-Lee's developed three essential technologies:
1. a system of globally unique identifiers for resources on the Web and elsewhere, the Universal Document Identifier (UDI), later known as Uniform Resource Locator (URL) and Uniform Resource Identifier (URI);
2. the publishing language HyperText Markup Language (HTML);
3. the Hypertext Transfer Protocol (HTTP).
This NeXT Computer used by Tim Berners-Lee at CERN became the first web server
The CERN datacenter in 2010 housing some www servers
The picture provides
Function
First, the browser resolves the server-name portion of the URL (en.wikipedia.org) into an Internet Protocol address using the globally distributed database known as the Domain Name System (DNS); this lookup returns an IP address such as 208.80.152.2. The browser then requests the resource by sending an HTTP request across the Internet to the computer at that particular address.
It makes the request to a particular application port in the underlying Internet Protocol Suite so that the computer receiving the request can distinguish an HTTP request from other network protocols it may be servicing such as e-mail delivery; the HTTP protocol normally uses port 80.
1. The content of the HTTP request can be as simple as the two lines of text.
GET /wiki/World_Wide_Web HTTP/1.1Host: en.wikipedia.org
2. If the web server can fulfill the request it sends an HTTP response back to the browser indicating success, which can be as simple as
HTTP/1.0 200 OKContent-Type: text/html; charset=UTF-8
3. followed by the content of the requested page. The Hypertext Markup Language for a basic web page looks like
<html><head><title>World Wide Web — Wikipedia, the free encyclopedia</title></head><body><p>The World Wide Web, abbreviated as WWW and commonly known ...</p></body></html>
Linking
Most web pages contain hyperlinks to other related pages and perhaps to downloadable files, source documents, definitions and other web resources (this Wikipedia article is full of hyperlinks). In the underlying HTML, a hyperlink looks like
<a href="http://www.w3.org/History/19921103-hypertext/hypertext/WWW/">Early archive of the first Web site</a>
Graphic representation of a minute fraction of the WWW, demonstrating
The picture provides
Such a collection of useful, related resources, interconnected via hypertext links is dubbed a web of information. Publication on the Internet created what Tim Berners-Lee first called the Worldwide Web (in its original CamelCase, which was subsequently discarded) in November 1990.
Over time, many web resources pointed to by hyperlinks disappear, relocate, or are replaced with different content. This makes hyperlinks obsolete, a phenomenon referred to in some circles as link rot and the hyperlinks affected by it are often called dead links.
The ephemeral nature of the Web has prompted many efforts to archive web sites. The Internet Archive, active since 1996, is one of the best-known efforts.
Enjoy the song that touch my heart.
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