W3C home > Mailing lists > Public > w3c-sgml-wg@w3.org > February 1997

Re: XML catalog draft

From: Peter Murray-Rust <Peter@ursus.demon.co.uk>
Date: Sat, 08 Feb 1997 11:06:25 GMT
Message-Id: <3256@ursus.demon.co.uk>
To: w3c-sgml-wg@w3.org
In message <199702080118.RAA04259@boethius.eng.sun.com> bosak@atlantic-83.Eng.Sun.COM (Jon Bosak) writes:
[... suggestion for XML catalogs ...]

I support the _idea_ of this proposal, because it gives an impetus to 
creating a managed namespace.  Sometimes such namespaces can be cheap
to create and it simply needs some-body to make a proposal which is
sufficiently convincing, and suffiently simple to implement that everyone
sees the value and adopts it.  (IMO MIME has some of these features though
it also has design flaws.)

At present the most obvious namespace management available to everyone
is DNS.  (For example, in 'Java in a Nutshell', p 19, O'Reilly show how
it can be used to provide a unique namespace for any Java package, e.g:
(The first two components are the domain name in reverse order).

I am not familiar with the URN process in detail - am I right in assuming
that it based on DNS?

> Let's suppose that "-//FOOCORP::FOOAUTH//DOCUMENT sometitle
> ver1.01//EN" fails to find resolution at the local level.  Postulate
> the existence of a server (probably mirrored, but let's stay above
> that level of detail for the nonce) funded by every organization that
> wishes to use this mechanism.  Let's call this server xmlid.net.  That
> server does not have a listing for every FPI; all it has is one (and
> only one) entry for every publisher that has joined the cooperative.
Jon, could you expand on this word, please?  If it means 'Those large 
corporations whose business is publishing information and who are prepared
to pay for a maintained site (xmlid.net) to be set up'.  If this is the 
case then it will lead either to a fragmentation of the community, or to 
a proliferation of 'xmlid.net's (e.g. 'xmlid.net.ac.uk', 'xmlid.bio.net')

> So on that server there is a single lookup table cached in RAM, one
> line of which consists of FOOCORP::FOOAUTH on one side and
> foodocs.foo.com on the other.

This server is going to have to be funded somehow, with a registration process
and removal of dead entries.  Will it, in itself, be able to scale to 
respond to demand or will there be a DNS-like system of servers?

> Add to the abilities assumed for the XML client under the XML catalog
> proposal the following: it can query xmlid.net with the string
> FOOCORP::FOOAUTH and get back foodocs.foo.com; it can then query
> foodocs.foo.com for its corporate catalog; and it can add that
> corporate catalog to its own for long enough to resolve the query (or
> fail, but that's entirely FooCorp's responsibility).
> This isn't enough to build a resolution mechanism, but it's enough to
> think that building one might be possible.  Is there anything
> basically wrong with the idea?

It seems to involve a mapping of organisations onto domain names.  For
example SUN:: would map onto sun.com (right?).  Is SUN:: the only
component of SUN or are there also SUNSOFT, SUN_MICROSYSTEMS, etc.
It seems to me that it is necessary to have a feel for the stability
of organisation names before you can get an idea of the work involved.

If domain names are a useful approach, what about the use of
something like:

This says, in effect, if your site (or server) has implemented XML then
this is reserved request for the XML catalog that relates to XML
information on that site/server.  
It's unlikely to clash with existing namespace (apart from people who
used XML for something else :-).  Webmasters could easily implement it, 
and it should be fairly straightforward to update the local catalog.


Peter Murray-Rust, (domestic net connection)
Virtual School of Molecular Sciences, Nottingham University, UK
Received on Saturday, 8 February 1997 07:47:14 UTC

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