Networking and Internetworking - Guide to Cloud Computing for Business and Technology Managers - page 58

external information. The other key invention that was relevant to Berners-
Lee was that of the mouse. This was invented by Doug Engelbart in the 1960s,
and it allowed the cursor to be steered around the screen.
The major leap that Berners-Lee made was essentially a marriage of the
Internet, hypertext, and the mouse into what has become the World Wide
Web. He was especially concerned with allowing communication across
computers and software of different types. He also wanted to avoid the
structure of most databases, which forced people to put information into
categories before they knew if such classifications were appropriate or not.
To these ends, he devised a Universal Resource Identifier (later called the
Uniform Resource Locator or URL) that could point to any document (or
any other type of resource) in the universe of information. In place of the
File Transfer Protocol then in use, he created a more sophisticated Hypertext
Transfer Protocol (HTTP), which was faster and had more features. Finally,
he defined an Hypertext Markup Language (HTML) for the movement of
hypertext across the network. Within a few years, these abbreviations, along
with WWW for the World Wide Web itself, would be as common as RAM, K,
or any other jargon in the computer field.
In order to create and display Web pages, some type of markup language
is necessary. While there are many types of markup languages, we will
briefly introduce three common types here: Hypertext Markup Language
(HTML), dynamic Hypertext Markup Language (dynamic HTML), and
eXtensible Markup Language (XML). HTML, D-HTML, and XML are mem-
bers of a family of markup languages called Standard Generalized Markup
Language (SGML). Despite the name, SGML itself is not a markup language,
but a description of how to create a markup language. To put it another
way, SGML is a metalanguage. Hypertext Markup Language (HTML) is a
set of codes inserted into a document that is intended for display on a Web
browser. The codes, or markup symbols, instruct the browser how to dis-
play a Web page's text, images, and other elements. The individual markup
codes are often referred to as tags and are surrounded by brackets (< >). Most
HTML tags consist of an opening tag, followed by one or more attributes,
and a closing tag. Closing tags are preceded by a forward slash (/). Attributes
are parameters that specify various qualities that an HTML tag can take on.
For example, a common attribute is HREF, which specifies the URL of a file
in an anchor tag (<A>).
2.4.1 Origin of the World Wide Web Browser
The invention of the WWW by Berners-Lee was a revolution in the use of the
Internet. Users could now surf the Web: that is, hyperlink among the millions
of computers in the world and obtain information easily. The WWW creates
a space in which users can access information easily in any part of the world.
This is done using only a Web browser and simple Web addresses. Browsers
are used to connect to remote computers over the Internet and to request,