In the scope of this document, we will use the following terms:

Centralized catalog

An Open Catalog that includes only comments and CATALOG directives pointing to other catalogs (or DELEGATE directives if supported).


A Document Type Definition. It specifies the syntax used in documents. Examples of well-known DTDs include: HTML, XHTML, DocBook, TEI, MathML, MusicML, etc. SGML and XML give a framework for writing DTDs.

Open Catalog

A set of directives defined by the OASIS TR9401 Catalog, mostly used for defining equivalences between FPIs (Formal Public Identifiers) and real file names (see TR9401:1997 on


A set of files assembled together for distribution. It includes RPMs, DEBs and any other kind of packaging system.

SGML/XML computer program

Any program used to view, edit, convert, use or apply any kind of treatment to a document written using a SGML or XML DTD (Document Type Definition). This includes command-line utilities as well as GUI-based applications.

Style sheets

Declarations or scripts that define formatting during some conversion or edition process of a SGML or XML document. They can be written in any style sheets language: CSS, DSSSL, FOSIs, XSL, ...

Super catalog

An Open Catalog pointing to all the centralized catalogs.