[Glossary]

<IMG SRC="!XanaOverview?.png">

  Xanadu is a client-server architecture, where the client, called a *Front-End*, provides the user-interface, and the server, called a *Back-End*, serves the data.  The link between the two is via an 8-bit clean link using either a TCP socket or a Unix named pipe.

0. [Types of Information]

0. [Front-Ends (Clients)]

   0. [Links and Usages]

   0. [Client - Command Line]

   0. [Client - Text Mode]

   0. [Client - Graphical Mode]

   0. [Client - HTTP Translator]

0. [Front-End --> Back-End Protocol]

   0. [Tumblers (Coordinates;Keys)]

0. [Back-End (Server)]

   0. [Docustore (Invariant Stream)]

      0. [Back-End --> Docustore Protocol]

   0. [Linkstore]

      0. [Back-End --> LinkStore? Protocol]

      0. [Sieving Operations]

   0. [Back-End <-> Back-End Protocol]

   0. [Back-End --> HTTP]

0. [User Administrative Account Issues]

The Back-End can be divided up into a database of links, a sieving/searching engine and a database of text.

The text database, or datastore, is conceptual a separate piece with a well-defined interface. Planning ahead, the datastore could be a DVD server with active data migration and/or a <A HREF="http://freenet.sourceforge.net">Freenet</A> node that circulates public data globally. In fact, the Freenet concept can provide the BE-to-BE data migration that Nelson talks about, moving frequently accessed data closer to the client.

<FONT SIZE=+1 COLOR=RED>Key Technologies</FONT>

o [General Enfilade Theory]

o [the fabled Ent]

o [Versioning]

o [Notes from David]