[sc34wg3] Subject Locators

Patrick Durusau sc34wg3@isotopicmaps.org
Wed, 08 Jun 2005 19:48:26 -0400


Through a mishap with my email address, some posts I sent in May did not 
make it to the list. This was written on May 13, 2005:


Steve Pepper recently wrote:

> This does not accord with my view of what a subject locator is. I
> thought there was broad consensus in the community that a subject
> locator is the locator (or address) of a subject; that resolving
> a subject locator returns the subject itself; and that subject
> locators can therefore only be used as identifiers for (network-
> retrievable) information resources.
> The current draft of the TMDM is pretty clear on this, at least in
> the glossary (http://www.jtc1sc34.org/repository/0588.pdf):
>  3.24 subject locator
>  a locator that refers to the information resource that is the
>  subject of a topic. The topic thus represents that particular
>  information resource; i.e. the information resource is the
>  subject of the topic.
>  3.8 information resource
>  a resource that can be represented as a sequence of bytes, and
>  thus could potentially be retrieved over a network
I have been reading Thomas Fielding dissertation 
(http://www.ics.uci.edu/~fielding/pubs/dissertation/top.htm) and the 
latest URI specification (RFC 3986) and while I agree the TMDM makes the 
distinction you set forth, I am not altogether certain it is a 
distinction we want to follow.

Reasoing that as Fielding makes clear in his dissertation the REST model 
(see section Representations, 6.2 REST Applied to URI, 6.2.1 
Redifinition of Resource, and 6.2.1 Manipulating Shadows) relies upon 
the notion that only a representation of the resource is ever returned.

 From your post, "resolving a subject locator returns the subject 
itself..." I read you as taking a different tack. Is that correct?

Hope you are having a great day!


Patrick Durusau
Chair, V1 - Text Processing: Office and Publishing Systems Interface
Co-Editor, ISO 13250, Topic Maps -- Reference Model
Member, Text Encoding Initiative Board of Directors, 2003-2005

Topic Maps: Human, not artificial, intelligence at work!