Whiteboard: GreenSysArch	last revised by 220.73.165.142 on Aug 17, 2005 3:13 am

Nature of their Mapping

Enfilades are unidirectional, one-to-one mappings, where a given key corresponds to a given datum. The choice of what is a key and what is a datum define three types of Enfilades used in Udanax-Green. For details of the enfilade algorithms, see the EnfiladeTheory and General Enfilade Theory whiteboards. In this paper we only cover how the enfilades are used.

Back-End Architecture Overview

Udanax-Green uses three types of enfilade; a one-dimensional form (Type I) and two two-dimensional forms (Type II). In the architecture there is only a single instance of the Type I, called the Grand Enfilade, which acts as a global map of content. The Type II appears in two variants, a single instance called the Span Enfilade, for storing multi-ended links, and an unbounded number of instances of POOM Enfilades which represent content rearrangement and quoting/transclusions. POOM Enfilades dangle off the bottom of the Grand Enfilade while the Span Enfilade is a totally separate data object.

Udanax-Green uses coordinates expressed as tumblers, or strings of digits separated by dots. Each such positive integer between the dots is a a digit and theoretically is unbounded in value, although in practice is limited to an unsigned long in this implementation.

These digits can be thought of in many ways, from military-style numbering, to the dewey-decimal library cataloging scheme to a base-infinity floating-point fraction. Udanax-Green uses tumblers to express part or all of region of a number line, running from 1 (one) to 2 (two). Like a floating-point number, there are an infinite number of positions between 1 and 2.

To specify a portion of a number line, you need two components; a displacement or distance from 0, and a width of how distance you are including. Tumblers are used for both of these, where the displacement value is often called a DSP, and the width a WID, for shorthand. A width of 1 (one) and a displacement of 1 (one) is a reference to the entire number line, also called the docuverse.

Udanax-Green further breaks down coordinates into a tuple of four nested location elements;

• server on which the content resides

• owner of content

• particular version and document

• specific content within a document

Each such element is represented by a tumbler of unbounded length. When combined, they form a path to the content, with each element separated by a tumbler digit of 0 (zero), e.g.

1.server.0.owner.0.document.0.content

Some examples are:

• "1.1" (server 1)

• "1.1.0.1" (server 1, owner 1)

• "1.1.0.1.0.1" (server 1, owner 1, document 1)

Conceptually this forms a filesystem, appearing like:

/server/owner/document/content

This analogy can be useful, as a particular version of a document can be considered to be a normal file in a directory tree. The path leading to the file is called an invariant-stream address, or IStreamAddr for short:

/server/owner/document

The remainer of the address, the content field, is called the variant-stream address, of VStreamAddr for short. It references a specific character or link within a document.

Internally to Udanax-Green, these two addresses are often kept separate and passed as separate arguments.

The IStream

IStreamAddrs are assigned to information or babtized in a hierarchical fashion, via the operations:

• create id representing our server

• create owner within a (server)

• create document within a (server, owner)

• create version within a (server, owner, document)

• insert/remove/rearrange text

Conceptually IStreamAddrs? are never deleted, retired or reused.

The VStream

The Variant-Stream or VStream is the permutation of data that represents a particular version. VStreamAddrs refer to positions within a specific version of a document.

The VStream of a document consists of several dataspaces, (a) any of which may be empty and (b) directly correspond to specific types of BottomCrums in Udanax-Green.

• VStream addresses beginning with a 1.n... may represent either original text entered into this specific document, or text from another document that is windowed into this one at a specific offset/width.

  If it is original text, it is broken up into small pieces and stored within TextCrums, on the bottom layer of the Grand Enfilade.

  If it is windowed text, a (block#, byte#) tuple pointing to the root of a POOM enfilade is stored in an OrglCrum?.

  code> ?

• VStream? addresses beginning with a 2.n... represent links that reside within (have as their home document) this specific document. Links may have multiple end-points all or none of which may point into this specific document.

Grand Enfilade

• Grand (granf) I - I

  Maps coordinates in the IStream? up to but not into the VStream? of a specific document. The VStream? is represented by either (a) a block of original text or (b) the root node of a nested POOM enfilade describing a permutation of the VStream? of this and/or another document that when rearranged, windows into this (position, width) gap in the IStream?.

  The Grand Enfilade is the starting point for front-ends reaching into the docuverse.

  Key: (a tumbler indicating a width along the IStream?)

  Datum: one of

  (a Crum containing a piece of original text)

  or:

  (a block#/byte# tuple pointing to a POOM enfilade)

  NOTE: By summing the width keys of each Crum as we descend thru the UpperCrums? of the Grand Enfilade seeking a position in the docuverse, we can derive our displacement within the docuverse and know when we have arrived.

  There is only one Grand Enfilade in the Udanax-Green system.

POOM Enfilade

Poom (poom) Permutation Of Order Matrix I - V

Maps coordinates from the VStream? to the IStream?

There are many POOM Enfilades in the Udanax-Green system, one for every rearrangement of the document content in use.

Key: (an IStream? displacement/width tuple)

Datum: (a VStream? displacement/width tuple)

The POOM says, in effect: given that there is a specific place and width of information in the docuverse, provide a map of how that information appears, in a linear fashion within that window, from the various pieces scattered elsewhere in the docuverse.

NOTE: Since POOMs? appear under BottomCrums? in the Grand Enfilade, you'd think a shorter relative IStream? would suffice. But by retaining the context of fully-qualified IStream? address in the key, a single POOM can be linked into an arbitrary number of Grand BottomCrums?.

Span Enfilade

Span (spanf) V - V

Maps coordinates from the VStream? to elsewhere in the VStream?

Key: (a displacement/width tuple in the VStream?)

Datum: (a displacement/width tuple elsewhere in the VStream?)

There is only one Span Enfilade in the Udanax-Green system.

The Span Enfilade is used to answer the questions:

• Given a range of characters on my screen, determine where/in which other documents those characters also appear.

The spanf finds the pooms that map to the i-span.

Rules

dispattivity:

closure: combining a dsp with another dsp returns a dsp.

associative: the property required to balance enfilades and ents

identity: necessary to take a coordinate (dsp in the same group) down and up levels in the enfilade without changing it. XI = IX = X

inverse: required to transform into and out of a local coordinate space. Xi(X) = i(X)X = i. A blank piece of paper is a terrible thing to waste...