[tdwg-guid] Handle System considered not interoperable with standard WWW and SW applications

Ricardo Pereira ricardo at tdwg.org
Wed Jun 6 14:21:11 CEST 2007

    Hi all,

    First I wanted to say that I second what Jason, Kevin, and Rich have 
said earlier in this thread. The issues we are discussing here are 
mainly about metadata modeling and they are relatively independent of our 
choice of identifying scheme. If we comply to the LSID HTTP proxy 
recommendations we proposed, then LSID and HTTP URLs would be almost 
equivalent. I say almost equivalent because of the arguments Donald put 
forward in his last message.

    I don't believe that the Handle system would be a suitable 
identifying scheme for our community, however. That is simply because 
the Handle System has its own proprietary system for performing content 
negotiation that is completely incompatible with the standard WWW and 
Semantic Web applications.

    In the Handle system, each handle has a set of values assigned to 
it. These values may be different representations of a digital resource, 
such as an HTML page or an RDF metadata record, or even a PDF file. Or 
can be any other types that a community agree upon. Each value is 
accessed by an index and a type. In our case types may be mapped to 
mime-types, but this mapping is only recognized by clients that are 
aware of the handle protocol. See section 3.1 of the informational RFC 
3651 (http://www.handle.net/rfc/rfc3651.html) for more information about 
"content negotiation" in the Handle System.

    The trouble is that this proprietary scheme is a brick wall for 
standard WWW and Semantic Web applications. These applications have no 
way of getting to the right object representation using standard content 
negotiation and thus the scheme can't be used to represent digital or 
real objects effectively. In fact, these applications won't know how to 
ask for different object representations and will then get whatever is 
defined as the default representation, which can be different for 
distinct handles. In some cases it can be a PDF, in other cases it 
can be an HTML page asking for payment to see the full article, 
and so on.

    For that reason alone the Handle System is not a feasible 
identifying scheme for our community. Again, only LSID (with the HTTP 
Proxy recommendations) and HTTP URLs present content negotiation 
mechanisms that are interoperable with standard WWW and SW applications.




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