Project Xanadu

Project Xanadu was founded by Ted Nelson in 1960 as the original hypertext project. It was referred to by Wired Magazine as "longest-running vaporware story in the history of the computer industry": the first attempt at implementation began in 1960, but it wasn't until 1998 that (incomplete) software was released. In the meantime, the World Wide Web came into being, fulfilling many of the project's underlying visions.



During his first year as a graduate student at Harvard, Nelson began implementing the system which contained the basic outline of what would become Project Xanadu: a word processor capable of storing multiple versions, and displaying the differences between these versions. Though he did not complete this implementation, a mock up of the system proved sufficient to inspire interest in others.

On top of this basic idea, Nelson wished to facilitate "nonsequential writing", where the user could choose their own path through an electronic document. He built upon this idea in a paper to the ACM in 1965, calling the new idea "zippered lists". These zippered lists would allow compound documents to be formed from pieces of other documents, an idea he would later refer to as transclusion. In 1967, while working for Harcourt, Brace he named his idea Xanadu, in honour of the poem Kubla Khan by Samuel Taylor Coleridge.

Ted Nelson published his visionary ideas in his 1974 book Computer Lib/Dream Machines and the 1981 Literary Machines. Computer Lib/Dream Machines is written in a non-sequential fashion: it is a compilation of Nelson's random thoughts about computing, among other topics. The books are printed back to back, to be flipped between. Computer Lib contains Nelson's thoughts on topics which angered him, Dream Machines discusses his hopes for the potential of computers to assist the arts.

In 1972, Cal Daniels completed the first demo version of the Xanadu software on a computer Nelson had rented for the purpose, though Nelson soon ran out of money. In 1974, with the advent of computer networking, Nelson revised his thoughts about Xanadu into a centralised source of information which he dubbed a "docuverse".

In the summer of 1979, Nelson led the latest group of his followers, Roger Gregory, Mark Miller and Stuart Greene, to Swarthmore. In a house rented by Gregory, they hashed out their ideas for Xanadu; but at the end of the summer the group went their separate ways. Miller and Gregory created an addressing system based on transfinite numbers which they called tumblers, which allowed any part of a file to be referenced.

The group continued their work, almost to the point of bankruptcy. In 1983, however, Nelson met John Walker, founder of Autodesk, at a conference for the people mentioned in Steven Levy's Hackers, and the group started working on Xanadu with Autodesk's financial backing.

While at Autodesk, the group, lead by Gregory, completed a version of the software, written in the C programming language, though the software didn't work as well as they wanted. However, this version of Xanadu was successfully demonstrated at the Hacker's Conference and generated considerable interest. Then a newer group of programmers, hired from Xerox PARC, used the problems with this software as justification to rewrite the software in Smalltalk. This effectively split the group into two factions, and the decision to rewrite put a deadline imposed by Autodesk out of the team's reach. In August 1992, Autodesk divested the Xanadu group, which became the Xanadu Operating Company, which struggled due to internal conflicts and lack of investment.

Charles S. Smith, the founder of a company called Memex (the name of the hypertext system designed by Vannevar Bush), hired many of the Xanadu programmers and licensed the Xanadu technology, though Memex soon faced financial difficulties, and the then-unpaid programmers left, taking the computers with them. (The programmers were eventually paid.) At around this time, Tim Berners-Lee was developing the World Wide Web.

In 1998, Nelson released the source code to Xanadu as Project Udanax, in the hope that the techniques and algorithms used could help to overturn some software patents.

The influence of Xanadu

Many of Project Xanadu's proposed features have found their way into other hypertext systems, including the World Wide Web and WikiWiki systems. Though lacking in the scope proposed by Nelson, transclusion is practised on the web. HTML's IFRAME element allows full web pages to be included within other pages, RSS aggregators provide compound web pages which consist of items from several locations. and the utopic/dystopic Googlezon’s autogenerated stories ( is an idea on how transclusion will become more and more widespread.

Though micropayments have been slow to take off, PayPal is slowly gaining acceptance on the web.

The web versus Xanadu

There are several reasons why the World Wide Web gained the popularity it now enjoys, while Project Xanadu remains a relatively obscure piece of computing history.

  • Complexity vs. Simplicity
    Project Xanadu contains many complex ideas. Transclusion in Xanadu allows documents to contain any part of any other document, whereas the web merely allows linking to complete documents. The web is compatible with existing file system ideas, while Xanadu would possibly require the use of complicated databases, which may be difficult to maintain.
  • Copyright
    Xanadu's model of transclusion may have proven unpopular with authors. Despite the facilities for authors of documents to be paid when part of their work was transcluded in another's document, there seems to be no guarantee that the authors of these documents would receive proper credit in the transcluding work. Many authors object to their work being used as the basis of the sort of derivative works which transclusion would allow, but feel comfortable with having their complete work distributed on the web.
  • Availability
    Perhaps the greatest factor is that, quite simply, the web was there, and it worked, while Project Xanadu is still incomplete.

Project Xanadu related projects under development


External links

de:Projekt Xanadu fr:Projet Xanadu pl:Xanadu


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