What is Hypertext

What is Hypertext ?

Hypertext is text which is not constrained to be linear.

Hypertext is text which contains links to other texts. The term was coined by Ted Nelson around 1965.

HyperMedia is a term used for hypertext which is not constrained to be text: it can include graphics, video and sound , for example. Apparently Ted Nelson was the first to use this term too.

Hypertext and HyperMedia are concepts, not products.

Hypertext conceives information as nodes and link networks forming navigable paths that can be toured, returned to and referenced.

It is a non-linear way of presenting information. Instead of reading or learning about things in the order predefined by an author, an editor or a publisher, the readers of a hypertext can follow their own path, create their own order – their own meaning out of the material.

A node is an integrated and self-sufficient unit of information. In electronic instances, nodes are often thought of as being small enough to fit on one computer screen, but a node can be as small as one word or occupy multiple pages.

In a Hypertext each node is a lexia. The authors prepare the lexias and the readers browse through these lexias using the different pathways they selected.

A link is the traversable connection between two nodes. An anchor is the visible region, which must be selected to activate the link.

Once an anchor is selected, the link is activated. If more than one link is available for the anchor, either a choice is presented to the reader, or the system selects from the possibilities according to pre-defined criteria.

The Memex

Vannevar Bush first wrote of the device he called the memex early in the 1930s. However, it was not until 1945 that his essay "As We May Think" was published in the Atlantic Monthly.

The memex is "a device in which an individual stores all his books, records, and communications, and which is mechanised so that it may be consulted with exceeding speed and flexibility".

A memex resembled a desk with two pen-ready touch screen monitors and a scanner surface. Within would lie several gigabytes (if not more) of storage space, filled with textual and graphic information, and indexed according to a universal scheme. All of this seems quite visionary for the early 1930s, but Bush did not think so.

The Internet and the World Wide Web

The Internet is the word used to describe the massive world-wide
network of computers. The word "internet" literally means "network of networks". In itself, the Internet is comprised of thousands of smaller regional networks scattered throughout the globe. On any given day it connects roughly 20 million users in over 50 countries.

The World-Wide Web is mostly used on the Internet but they do not mean the same thing. The Web refers

to a body of information, an abstract space of knowledge, while the Internet refers to the physical side of the global network, a giant mass of cables and computers.

The HTML and XHTML documents we see on the World Wide Web are the best-known example of a hypertext system, but it is not the only one. Hypertext doesn't necessarily have to include links to documents in other places; a simple hypertext system can live on a single computer.

The basic web page building tool is HTML code (Hyper Text Markup Language).

HTML was developed from a more powerful and elaborate computer language called Standard Generalized Markup Language (SGML)

A Web page consists of only text and special instructions called tags < >

An HTML document usually has the .htm or .html extension

A Web browser interprets the tags in an HTML document and displays the document on the computer screen

HTML documents transfer quickly over the Internet since they only contain text, however, accompanying graphic files might slow down the transfer process.

An HTML document can be displayed on any type of computer (Macintosh, IBM compatible, UNIX)

The World Wide Web (WWW) combines computer networking (the Internet) and Hypertext MarkUp Language (HTML) into an easy to use system by which people can access information around the world from a desktop computer.

We commonly think of links as the underlined text on graphical Web browsers, such as Netscape and Internet Explorer, which, when we click it, takes us to a new document or other type of information. Before there was a graphical Web browser, computer users could access linked material on the Internet by using a program such as LYNX, a non-graphical Web browser.

A web browser is software that interprets the HTML codes in web pages so that we can view them in a readable format.

Every page on the Web has a unique URL (Uniform Resource Location). The URL gives you the address of the page.

HTTP, short for HyperText Transfer Protocol, is the underlying protocol used by the World Wide Web. HTTP defines how messages are formatted and transmitted, and what actions Web servers and browsers should take in response to various commands. For example, when you enter a URL in your browser, this actually sends an HTTP command to the Web server directing it to fetch and transmit the requested Web page.