[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message]

Re: DNS based URIs that don't imply access method

• To: tbray@t... (Tim Bray)
• Subject: Re: DNS based URIs that don't imply access method
• From: John Cowan <jcowan@r...>
• Date: Thu, 25 Jul 2002 18:42:23 -0400 (EDT)
• Cc: xml-dev@l...
• In-reply-to: <3D4079CC.2050908@t...> from "Tim Bray" at Jul 25, 2002 03:21:00 PM

Tim Bray scripsit:

> Hmm.... the more I learn about URNs, the fewer use-cases I can imagine. -Tim

The basic use case for URNs is having a collection of unique standardized
labels for things (computerized or not) and making them interoperate
with URLs even though retrieving representations is not practical.

Consider the news: URL scheme, which is functionally an URN.  It doesn't tell
you how to retrieve the article (unlike the nntp: scheme); relative news:
URLs make no sense; it is a unique label for something (a Usenet article)
that exists in multiple copies around the world.

Similarly, the urn:newsml: scheme provides a unique label for Real
World news articles, with four subparts: domain name of originator,
date of ownership of the domain, local-part, version number.  Again,
relative URIs make little sense here.

The ISBN and ISSN numbers for books and periodicals (the whole periodical,
not a particular number) also say nothing about retrieval and are mapped
by the urn:isbn: and urn:issn: schemes.

The urn:oid: scheme represents ASN.1 Object Identifiers, which are
hierarchical sequences of numbers used to label various computer-related
things.  For example, urn:oid:1.3.6.1 is the Internet itself.

The urn:ietf scheme labels RFCs and their friends:
ftp://ftp.isi.edu/in-notes/rfc2648.txt is an URL for that particular
instance of RFC 2648, but urn:ietf:rfc:2648 is RFC 2648 itself.

Finally, there is an URN scheme for the persons in the Internet Whois
database, people who are technical or administrative contacts for
particular DNS domains.

-- 
John Cowan
        jcowan@r...
                I am a member of a civilization. --David Brin

• Follow-Ups:
  • Re: DNS based URIs that don't imply access method
    • From: "Alaric B. Snell" <alaric@a...>

• References:
  • Re: DNS based URIs that don't imply access method
    • From: Tim Bray <tbray@t...>

• Prev by Date: RE: DNS based URIs that don't imply access method
• Next by Date: Re: DNS based URIs that don't imply access method
• Previous by thread: Re: DNS based URIs that don't imply access method
• Next by thread: Re: DNS based URIs that don't imply access method
• Index(es):
  • Date
  • Thread