The roots of hypertext lie in the work of Vannevar Bush (1945) who was concerned about the explosion of scientific literature which was making it impossible for even specialists to follow new developments in their field. He felt that in the near future there would be a need for a new system which would help people to store and access information more easily.
Based on this idea Bush sketched the outlines of a device which he called MEMEX. A MEMEX (Memory Extender) 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 speed and flexibility. It is an enlarged intimate supplement to his memory." (Bush 1945). Although never implemented it was envisaged that a MEMEX would store information on microfilms which people would be able to access using projectors from their desks. An important feature of the MEMEX device was associative indexing. Associative indexing allows items to be associated such that an item may cause another item to be selected automatically.
Doug Engelbart and Ted Nelson elaborated on Bush’s concept of the MEMEX in the 1960s. They envisaged computers building and manipulating interconnected bodies of text which Nelson named hypertext.
Nelson proposed a docuverse (document universe) where "Everything should be available to everyone. Any user should be able to follow origins and links of material across boundaries of documents, servers, networks, and individual implementations. There should be a unified environment available to everyone providing access to this whole space." (Nelson 1987).
Despite the early work by Bush and Nelson it was not until the mid-1980s that computers became powerful enough to support substantial hypertext systems.
A system of this era was The Symbolic Document Examiner (Walker 1987). The primary function of this system was to allow instant access to the contents of reference manuals for the Symbolics workstation via a hypertext interface.
Although not a success (Baecker et al 1995) the Xerox PARC Notecards system (Halasz 1988) allowed blocks of text and graphics to be linked together. Within this system index card sized blocks of text and graphics, called Notecards, are connected by typed links (connecting objects) as a semantic network. Notecards is a tool for displaying, modifying, manipulating and navigating through the network.
In 1987 HyperCard was released and provided free with Apple Macintosh computers. HyperCard consists of an interface builder and a scripting language that allows hypertext systems to be quickly built. The success of HyperCard led to a wider familiarity and greater acceptance of the hypertext concept.
In 1992 Tim Berners-Lee (Berners-Lee 1992) developed a hypertext system for the thousands of physicists at CERN in Switzerland to make it easier for them to write and share reports and scientific papers. The system was so useful that he made both his server and his text browser freely available to anyone who wanted a copy. The server responded to document requests by delivering a file to the browser. The server used the HTTP protocol which was very similar to the FTP file transfer protocol and used ASCII commands. Documents were written in the HyperText Mark-up Language (HTML). The widespread uptake of the software led to the foundation of the World Wide Web (WWW).
Authored by Serengul Smith
E-mail to:
serengul1@mdx.ac.uk
School of Computing Science Middlesex University
Revised: September 1998