This page is the beginning of a set of notes relating to my proposal for an online Formal Public Identifier (FPI) registry and resolution system based on the URN proposals.
The system would enable public identifiers to be used in document instances and enable the resolution of such public identifiers to public text situated on the Internet.
A WWW user agent, for example, coming across
<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
could resolve the FPI to the actual DTD in some registered location on the Internet.
My vision for the World Wide Web involves SGML browsers fetching texts, DTDs, images, fonts, style-sheets and applets via such an FPI resolution scheme.
My current proposal Delegating SGML Open Catalogs is now on its fourth revision (dated 1996-3-13).
Leaving aside certain technical questions (eg character sets, the
leading urn:), the proposed syntax of a Uniform Resource
Name (URN) is currently:
The name_specific_string in turn consists of a naming_authority (if there is one) and a locally_unique_string. URN registries will map namespace_identifiers or namespace_identifier + naming_authority pairs to a resolution scheme.
urn:namespace_identifier:name_specific_string
I now believe SGML catalogs hold the key to FPI resolution across the Internet.
Whitespace and comments (enclosed by --) aside, an SGML catalog consists of entries taken from the following possible types:
where
For more information, see SGML Open's TR 9401:1995 which contains the specification for catalogs.
What does DNS have to do with FPI resolution? Well, in a lot of ways FPI resolution is to SGML Open Catalogs what DNS is to the old host tables. There are bound to be some important lessons to be learnt from the DNS.