Xanadu

Introductory videos

Playlist Of Ted explaining Xanadu.
Key People: Ted Nelson, others...
Visible Connections / Visual Parralelism

Lump file Vs Send for file

The principle of Indirection.
In a lump file, the hyper layer is incorporated into the content layer. In HTML, you may set some text as a title with the <h1> tag, and you may ancar some text to somewere else with an <a> tag, but the former is content level, and the latter is hyper level. How in this scheme can you have backlinks? These kinds of connections are nesseseraly one way.
If, however we seperate out the hyper level information from the content level information we can enable two way links. In xanadu the document has a list of content, (CONTENT PORTION ADDRESS) called an Edit Decision List (EDL). This list is loaded, then the portions are sent for. Thus document structure and its content are uncoupled, identical content can appear in multiple documents, and thus the two way link semantics is at hand.

Implementations

    The Hypertransaction System at Keio University
    This was an indirect document hypertext system that included a payment system, were by readers would pay authors for the sections of their work that they revived, regardless of the EDL that pulled it in.
    OpenXanadu
    Avalable online accsessable via a web browser. A simulated inderect document.
    Xanadu Cambridge
    Ted has a video demonstrating this system.
    Xanadu Classic
    Both an operating system and a document management system. Not sure what that means exactly.
    It uses a Tumberler system. It seems to be a start and a span for specifying a slice of a sequence. However the start and span seem to be writen with multiple dots like an IP address. Maybe this is just like an ip address, ie an incoding for 32-bits. Or perhaps its a tree incodeing? Like a base-infinity number system. Apparently described in the book literary machines.
    Enfilade, a tree structure documents so that editing is referential rather then direct. This make handling large documents more tractable.
    Enfilades should have a "downward property" like rearranging text, and an "upward property" like inserting text.
    Grandfelade, system for managing the data accross the network.
    Spanfelade, manages all the spase in a document. It is the union of all its spans. comparing documents means finding the union of there spanfelade.
    Pommfilade manages each document as a permutation matrix of texts and links. The matrix is represented in thumbelers.
    Xanadu Space
    This looks very cool but completely insane. Maybe in VR. Very impressive. Sounds like the software is so complex, progress on it is intractable