- From: <noah_mendelsohn@us.ibm.com>
- Date: Tue, 19 Mar 2002 14:21:12 -0500
- To: Chris Lilley <chris@w3.org>
- Cc: Mark Baker <distobj@acm.org>, www-tag@w3.org
Chris: I think you've set down a very nicely balanced re-expression of what I was trying to say. I especially like: >> The useful balance point is to have a small >> selection of common protocols and to invent >> new ones when necessary. I think we're close to converging, but I would still quibble a bit with: >> but to argue (which I don't think you are, >> but just to be sure) that there should be no >> mention of XML in case it gets replaced in 20 years >> leave a minimal, and uselessly impractical, architecture. Well, I think I'm suggesting a layered approach to the architecture, with one document (or set of docs) that sets down the principles that are truly foundational to the web. We should expect the rules captured there to last indefinitely, with only occasional evolutionary change. I see URI's as fundamental, but not HTTP or XML. I'm unsure about scheme names as a means of dividing the protocol space and the name space (e.g. http:). They seem to be a foundational aspect of URI's, but we know that they have some limitations and may need to be revisited at some point. I suspect schema names (as a concept, not individual ones) make the cut. I would probably include REST as a foundational principle to be applied to the subset of resources that model well as a distributed memory (I know there is unresolved debate, and some believe it applies to more than that.) I would then layer on that documents that describe the web architecture as we have deployed it. That's where I'd put http, XML, etc. The Web can fundamentally exist without XML, IMO. It did before and it could again. Just for comparison, if I were writing the Internet archtecture in this style, IP and IP addresses would be in the foundation layer, but TCP would not. I think the Internet would still be the Internet if TCP were replaced. If IP turned into virtual circuits, I think that would be a completely different system. So, a layered archtecture. No mention of XML in the foundation, but lots of emphasis in the next layer up. That's what I'd suggest anyway. ------------------------------------------------------------------ Noah Mendelsohn Voice: 1-617-693-4036 IBM Corporation Fax: 1-617-693-8676 One Rogers Street Cambridge, MA 02142 ------------------------------------------------------------------ Chris Lilley <chris@w3.org> 03/18/2002 05:46 PM Please respond to Chris Lilley To: noah_mendelsohn@us.ibm.com cc: Mark Baker <distobj@acm.org>, www-tag@w3.org Subject: Re[2]: section 1, intro, for review On Monday, 18 March, 2002, 23:00:30, noah wrote: nuic> Mark Baker writes: >>> I would prefer it if the special role of HTTP was at least alluded to. nuic> This is a point which Mark and I have occasionally discussed in private. nuic> No doubt, HTTP plays a distinguished role in the Web today and for the nuic> forseeable future. Still (and I suspect Mark doesn't agree) I don't see nuic> why our architecture should imply that the web would diminished in quality nuic> if HTTP were eventually displaced by other protocols. Indeed, I see this nuic> possibility of evolution as important to allow for changing applications, nuic> new hardware/software, and to enable access to more diverse sorts of nuic> resources over time. Clearly. nuic> If we didn't have universal naming, there would be no web; if the widely nuic> deployed protocols evolve over time, I think we're fine. Thus, and I nuic> know this is controversial, I prefer a formulation in which the nuic> foundational web architecture is just URI's, with no particular protocols nuic> or schemes distinguished or preferred. I agree with your first point but conclude that the second is too rigorous. nuic> Whatever protocols we deploy at this or that point in time are to promote nuic> interoperability for access to (representations of or information from) nuic> resources. If the TAG wants to write a separate document on "Web nuic> architecture in 2002", I think http should indeed be identified there as nuic> playing a distinguished role. I think this division into "unchanging web architecture" and "best current practices" is a useful one, but the cutoff date from one to the other is vague. Its possible to derive or extrapolate the former from the latter, (and that is my preferred method of reality checking top-down, theoretical approaches to architecture) but the period of currency of best practice is uncertain. For example, saying that markup should use XML, or XML 1.0, or XML 1.0, or XML 1.0 SE have different periods of usefulness; but to argue (which I don't think you are, but just to be sure) that there should be no mention of XML in case it gets replaced in 20 years would leave a minimal, and uselessly impractical, architecture. So I am happy to note that <i>currently</i>, HTTP enjoys widespread use; that new applications should use it rather than needlessly inventing new protocols, etc. I agree this might change, but I would not want to restrict it to a particular date range because we don't know in advance what range that is. There is also a practical point, the tension between innovation and conservatism which penalizes moving too far in either direction; its all very well to say that new protocols can be invented, and so they can, but if every single document uses a new protocol we are in trouble. Likewise if we were to force pop, smtp, irc etc to all use HTTP. The useful balance point is to have a small selection of common protocols and to invent new ones when necessary. Which all seems self evident, I guess, but worth noting to guard against the unlikely extreme of a top-down approach that either bans all mention of HTTP, or alternatively mandates it everywhere. -- Chris mailto:chris@w3.org
Received on Tuesday, 19 March 2002 14:38:33 UTC