RE: Namespace name: better to use URN or URL?

["Bullard, Claude L (Len)" <clbullar@ingr.com>]

Philosophically, I prefer a URN.  As you say, it 
is clear what it is, and practically, the systems 
I work with don't color it blue and make it clickable; 
that is, it isn't a hyperlink.  Practically, some 
of us are tool thralls and the tool vendors 
make that choice for us.

We've debated it endlessly, but I think using a 
URL binds it to the web by using a system 
specific location identifier in the namespace, 
and that pollutes the namespace in situations 
where the information could be reused on non-Internet 
systems.  One has to decide if the information 
is ever to be repurposed off the internet.  
When we had this argument some time ago, it 
came down to, do you ever plan to resolve it? 
If it is *really just a label*, no winking, 
no nudging but honest clean design, one has 
to choose for themselves and decide if 

http://anything 

really is a name or a location.  Identity 
is not the horse you want to ride for that 
argument.  Systems sit inside systems and 
that is the problem and solution to describing 
a namespace.

Len 
http://www.mp3.com/LenBullard

Ekam sat.h, Vipraah bahudhaa vadanti.
Daamyata. Datta. Dayadhvam.h


-----Original Message-----
From: Roger L. Costello [mailto:costello@mitre.org]
Sent: Thursday, August 30, 2001 7:22 AM
To: xml-dev@lists.xml.org
Subject: Namespace name: better to use URN or URL?


Hi Folks,

Is there any advantage to formulating a namespace name as a URN, vice
formulating it as a URL?

Example:

    urn:publishing:book

versus

    http://www.publishing.com/book

As I see it, 

- the advantage of formulating a namespace name as a URN is that it's
easier to conceptualize a URN as a "name" and not a "location". 

- the advantage of formulating a namespace name as a URL is that the
namespace "could" then have a dual purpose - it could serve both as a
name and as a location to "something".  I am ashamedly ignorant of RDDL,
but I vaguely recall reading something about using a namespace URL to
point to a RDDL document.  Does RDDL enter into this issue?  

My impression is,

A couple years ago there was a general feeling in the XML community that
URNs were the preferred form for namespace names, but recently there
seems to be a shift towards preferring URLs.  Do you agree?