Appendix D

account An account is the system's representation of a user. The account includes that users' documents. Users can have multiple accounts.

Be Short for backend.

backend One of two high-level modules required for a Udanax Green hypertext system. The backend is responsible for document and version storage, link management and editing. In many installations it will run on a more powerful computer networked to the individual workstation where users work. (See "frontend".)

data-byte The smallest addressable unit of storage in the Udanax Green FeBe Protocol. A data-byte is an eight bit unsigned binary number.

data space The part of a document that contains arbitrary data, supplied by the user or front-ends. The other space in documents is the link space.

document A block of information in a hypermedia information pool that is thematically unified. Such documents resemble contemporary paper documents except that clips of animation, pictures, and sound tracks may also be documents. Also, in fully integrated hypermedia systems, the typical document will likely be smaller in size - closer to the length of an article in a newspaper than to the length of a book.

docuverse The abstract address space that contains all Udanax Green objects.

end-set The sets that describe links. Each link has three end-sets: a from-set, a to-set, and a three-set. The three end-sets are operationally the same, but by convention, links start at the from-set and end at the to-set, and have a type as defined by their three-set. Each link also has a home-set.

Fe Short for frontend.

FeBe Protocol Frontends communicate with the backend using a standard, public protocol called FeBe (stands for "Frontend Backend"). Other sections of this package describe the preliminary protocol used by the current system.

from-set The set of elements from which a link `starts'. (See "end-set".)

frontend One of the two high-level modules required for a multi-user Udanax Green hypertext system. The frontend is responsible for presenting the information from the backend to the user on his or hers workstation. (See "backend".) It supports users in reading, creating, and editing information.

home-set The set of documents that actually contain a given link in their contents. Note that the home of a document is independent from any of its end-sets.

hypertext Any form of non-linear writing. This includes paper mechanisms such as table of contents and indexes. Computerized hypertext allows readers to navigate through large quantities of information.

hypermedia Everything that hypertext does, but NOW IMPROVED! NOW WITH PICTURES, ANIMATION, AND SOUND!

ID A global tumbler address of a document, link, data-byte, etc. The ordering of the addresses groups related things. For example, the documents of a single user have contiguous addresses.

The component of a hypertext document that describes and maintains interconnections between blocks of information. In Udanax Green a link has three parts. (For a complete explanation, please read the chapter "Links and Link Types".) Frequently, however, the pieces have the following usage: the from-set describes the block of information from which the link originates, the to-set describes the block of text to which the origin is linked, and the three-set describes the link's type.

links:link space The part of a document in which links reside. The other space is the data space.

node A running Udanax Green backend, and all information it contains.

span An span specifies a range of tumblers with a starting tumbler and a tumbler width. The span includes all tumblers between the start inclusive and the start plus the width exclusive. (See the chapter "Tumbler Arithmetic".) Because of the uniformity of addressing, spans can represent ranges of data-bytes, links, documents, and even users.

spec Many of the FeBe operations use a set of specs to specify a set of arbitrary Udanax Green objects. A spec is either a span of globally addressed elements like documents, or a document identifier and a set of vspans (document local spans).

three-set The end-set which determines the type of a link, by convention.

to-set The end-set which a link points to, by convention.

tumbler Tumblers are multi-part ordinal numbers similar to the Dewey Decimal System. For example, and are both tumblers. Since they can expand at any point, a numbering system based on them never runs out of precision. Udanax Green uses tumblers for all address to allow any number of nodes, users, documents, data-bytes, and links. (See the chapters "Addressing" and "Tumbler Arithmetic".)

A document initially created as a virtual copy of some other document.

vspan A vspan describes a range of the contents of a single document. Like a span, a vspan has a start and width tumblers. The tumblers are relative to the document, however. The vspan designates everything between the start tumbler inclusive and the start plus the width exclusive. The width can cross the boundaries of space within the document. (See the chapter "Addressing".)

width The size of a span; the sum of the origin tumbler and width tumbler is the first thing past the end of the span.

Udanax Green A hypertext backend designed to allow multiple concurrent users to have fast retrieval and update of hypertext information pools of unbounded size.

Udanax Green:Udanax Green objects Nodes, accounts, documents, links, and data-bytes are all objects in the Udanax Green address space (also called "the docuverse").