Re: Documents, Cars, Hills, and Valleys

On Fri, 19 Apr 2002, Tim Berners-Lee wrote:

> If you say that an HTTP header identifies a car, and then a GET returns a
> picture, how do you refer to the picture?

Tim, this problem is no different to those we run into with more
traditional http:-named informational resources. Representations are
transferred, either of informational or physical systems / entities.
Sometimes we don't have a URI name for each distinct bytestream
representation. Whether the representation is of a physical thing or not
is irrelevant to this problem.

http://www.w3.org/Icons/WWW/w3c_home

If you say that an HTTP header (or http:-URIref) identifies a visual-work,
and then a GET returns an image/jpeg or image/png bag of bytes, how do we
distinguish between these three things? A partial answer might be
reference-by-description: 'the image/png representation whose sha1sum is
yaddayadda'.

Why make work for ourselves? What worldy benefit is there in coming up
with criteria for splitting the world into two huge disjoint categories:
'things that can be named with http:-uris, and things that can't'? Sure,
the HTTP spec has woolly words about network / informational / resources
and/or services, but what inferences do such vague categories buy us?
Whatever happened to minimally constraining architectures...?

Dan