Subject: A question about Web history and vision To: "John A. Kunze" , Larry Masinter , "Roy T. Fielding" Date: Mon, 24 Nov 2008 12:54:51 +0000 [[PGP Signed Part:Henry S. Thompson ]] As you all know, I sit on the W3C TAG, where among other things I try to make sense of this URI thing we all care about. In writing a layman's tutorial introduction to the subject, a question has arisen I don't know the answer to, and a trawl through the history, as recorded in various RFCs, only deepens the mystery. As authors of the RFCs involved (1736, 1737, 2396), I would welcome your insight into the following: When and why did the 'Resource' of URL/N/C/I become understood as distinct from retrievable representation? In particular, when did the possible of in-principle non-representable resources get included in the range of URIs? Here are some reminders about the historical record as I read it. TimBL's early RFC (1630) never defines 'resource', or talks much about resources at all. As the subtitle of the RFC suggests (A Unifying Syntax fo rthe Expression of Names and Addresesof Objects on the Network as used in the World-Wide [sic] Web), when TimBL needs to talk about what URIs identify in this document, he uses the word 'object'. The language used in 1630 about objects (they can be "accessed" or "retrieved", they are "part of systems" or "in a machine's local file system", they can have "operation[s] applied to [them]", they can have URIs "within [them]", "a group of [them] [can] be moved, they have content types)" suggests at that point TimBL had in mind something much more like representations than what we now understand by the word "resource". The following curious sentence does appear, which points towards one line of motivation which will later emerge for the resource-representation distinction: "Fragment identifiers do NOT address the question of objects which are different versions of a 'living' object, nor of expressing the relationships between different versions and the living object." The next stage of development is manifest my the uneasy partnership of 1736 and 1737. 1736 contains the first appearance that I have found of what will become the orthodoxy of 2396 and 3986: "Locators may apply to resources that are not always or not ever network accessible. Examples of the latter include human beings and physical objects that have no electronic instantiation (that is, objects without an existence completely defined by digital objects such as disk files)." But 1737 (and indeed 1738) appear to have no such general meaning in view. 1737 says "In order to build applications in the most general case, the user must be able to discover and identify the information, objects, or what we will call in this architecture resources, on which the application is to operate. Beyond this statement, the URI architecture does not define 'resource.'" 1738 doesn't even go this far, and uses 'resource', 'Internet resource' and '[data] object' more or less interchangeably. Four years later, in 2396, we have the fully articulated position -- anything can be a resource, and representations are what is retrieved, not resources. Resources whose representation is time-varying are explicitly acknowledged (I'm guessing this comes from Roy's interest in this case as discussed in his PhD). So, any memories or reconstructions of rationales would be welcome of why the generalisation happened from, shall we say, network-accessible data objects, to anything with identity. [John, given the extract above, the particular question for you is how or why the idea of resources which "have no electronic instantiation" emerged. Why would you coin a network 'locator' for something which by its nature could not have a network location?] Thanks! ht