Re: [topicmaps-comment] referring to a topic from outside a TM -- PURL

["Thomas B. Passin" <tpassin@comcast.net>]

[Bandholtz, Thomas]

See what just has been recommended by PubSubj:
(http://www.oasis-open.org/committees/tm-pubsubj/docs/recommendations/psdoc_
04.htm)
"4.4.1 - Every PS Indicator in a PS DocSet shall be identified by, and
retrievable through an unique canonical URI.
This canonical URI is the corresponding PS Identifier, uniquely defined in
the PS DocSet namespace."
Note: ***Every*** PS Indicator, not only the whole set.

{Tom]

I'm actually against making this mandatory, although it's good practice to
do so when possible.  Here's why:

1) Right now, anything retrievable through such a URI must be read and
understood by a person, there is no topic maps mechanism to let a processor
understand the "meaning" of the PSI.  Being online does not seem to be an
runtime requirement for processing, but rather a design time benefit for
software and map creators. So any means by which a person can get the
information should be ok.

2) It prevents people from creating useful PSIs if they don't have a stable
website.

3) It would seem to invalidate previously PSIs whose web site goes away for
some unfortunate reason, even when the copies of the information are
available on many other web sites.

4) If technology were to change and so the owner of a set of PSIs were to
want to host it using some other protocol or technology, they would not be
able to make the change, since that would break the existing PSIs.

For these reasons, I strongly suggest that it be a matter of good practice
rather than mandate to have the PSIs be retrievable from their URI.

Cheers,

Tom P