W3C home > Mailing lists > Public > www-tag@w3.org > July 2002

RE: httpRange-14 , what's the problem

From: Nick Kew <nick@webthing.com>
Date: Sat, 20 Jul 2002 01:01:09 +0100 (BST)
To: <www-tag@w3.org>
Message-ID: <20020720003219.G1469-100000@fenris.webthing.com>

>	Annotea, for example, is a live and
> shipping product of W3C which allows people to publish assertions about
> "the thirteenth character in the HTML representation",

Annotea is an experimental system that show up numerous problems in
diving straight in with mismatched technologies such as RDF and HTTP.

1. Annotea uses something it calls XPointer, which it applies
   indiscriminately to to HTML and Tag-Soup, as well as to XML.
   Annotea's pointers are not well-defined.

2. Annotea makes no provision for content negotiation.  So the subject
   of an annotation is ill-specified.

3. Annotea doesn't even try to deal with content change.  There is no
   way of telling whether an annotation applies to the page[1] as-is or
   as-was at some unspecified time in the past.

4. In the event of a content change being detected (e.g. with HTTP
   Last-Modified, Etag, etc), there is no way to tell whether the
   change affects the validity of the annotation.

I recently posted references to my discussion of these problems,
but just to recap:


[1] if you want to question my use of "page" at this point, that's
another problem - but not one I choose to consider here.

Nick Kew

Available for contract work - Programming, Unix, Networking, Markup, etc.
Received on Friday, 19 July 2002 20:01:29 UTC

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