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Re: Fwd: Persistent caches - was: Are *relative* URIs as namespace nemes considered harmful?

From: Norman Walsh <ndw@nwalsh.com>
Date: 18 May 2000 11:38:05 -0400
To: xml-uri@w3.org
Message-ID: <877lcrg97m.fsf@nwalsh.com>
[This was just forwarded to me today; somehow I failed to join
this list earlier in the week, apologies for anything I take out
of context.]

>From: "Tim Berners-Lee" <timbl@w3.org>
>To: "Pawson, David" <DPawson@rnib.org.uk>, <xml-uri@w3.org>
>Date: Wed, 17 May 2000 18:57:56 -0400
>Subject: Persistent caches - was: Are *relative* URIs as namespace nemes 
>considered harmful?
>-----Original Message-----
>From: Pawson, David <DPawson@rnib.org.uk>
>To: xml-uri@w3.org <xml-uri@w3.org>
>Date: Wednesday, May 17, 2000 3:16 AM
>Subject: RE: Are *relative* URIs as namespace nemes considered harmful?
> >Borrowing from Norm Walsh, the debate seems to centre on
> >names and addresses, [1].
><rant>Norm's first reference is to my rant [2] about the illusion involved
>naively dividing identifiers into "names" and "addresses".
>His paper suggests taking the XML community from the state of
>having a global namespace with an international body managing
>its delegation hierarchy and a set of time-tested protocols to manage
>its distributed catalog service to a state which Internet folks will
>recognize as the "/etc/hosts" level of civilization.  

I think your gloss of my article is inaccurate and misleading.
I never suggested catalog files as the appropriate, global
indirection mechanism for the web. I wrote the article to
describe a set of Java classes that I wrote for using catalog
files, so naturally the bulk of the article describes catalog
files. Catalog files are useful, indepedant of this debate or
either of our opinions on it.

The only reason that I made reference to your article, which *I*
did not catagorize as a rant, was to express that while I don't
think that names and addresses are the same thing, there are
others who do.

>(When the
>Internet was very young, my best beloved, then there were not very many
>nodes on it.
>But Norm prefers using that non-URI namespace, the FPI. Because why use a
>great big deployed system when you
>only have a little problem?.... </rant>

[aside: I think your patronizing tone is inflammatory and offensive.]

FPIs are useful. They are clearly names and not addresses and
they are a widely deployed mechanism for reference documents in
a system-independent manner. However, I think URNs are just fine
for that purpose too, and I don't have a strong feeling one way
or the other about FPIs vs. URNs.

I would very much like to see a widely deployed URN resolution
mechanism that did not rely on catalogs.

But I have completely lost patience with the use of URLs as
names.  I am just sick and tired of manually editing system
identifiers because I have DTDs or Schemas stored in a different
location than my colleages or because I don't want to wait for a
*static* document that *I've already got on my local system* to
come to me over my 28.8 link to the outside world.

>FPIs are not in the universal information space of the web.  This means they
>are not as powerful. They cannot be used in so many ways.

What do you mean by "not in the universal information space of
the web."?  How are they abstractly less powerful? I don't see
how they are theoretically any less powerful. Catalog files are
(one example) of the clear ability to map from one space to the other.

>If the social conditions (control,
>persistence) are things
>this community really likes, then it would be quite simple to define a URI
>scheme fpi: which
>would fix this. 

A URN by any other name...

>That could easily become a W3C activity - so long as they
>could be justified
>as giving something which existing URI schemes don't.

It doesn't need to be a W3C activity, URNs are already fully
described by several RFCs. There's even a reasonable
registration authority in place.

> >If names are intended, then the string
> >value of an absolute uri is sufficient (ignoring the uniqueness debate).
> >If addresses are required, then a local resolution via a catalog would
> >suffice to convert the name into an address. A global solution
> >would then be available via the web without the catalog usage.
>Yes. This is true.   Many of the people I talk to assume this is the case.
>Some browsers keep such a catalog already, with actual local filenames
>completely hidden from the user.  I would recommend this solution for
>XML software in general.

That's part of the solution. One still needs a discovery mechansim.
Handed a name, you have to know who to ask for the address. (And there
could be several: the closest, the authoritative, etc.)

                                        Be seeing you,

Norman Walsh <ndw@nwalsh.com> | Why shouldn't things be largely absurd,
http://nwalsh.com/            | futile, and transitory? They are so,
                              | and we are so, and they and we go very
                              | well together.--Santayana
Received on Thursday, 18 May 2000 11:38:09 UTC

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