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Minutes of 24-25 Sep 2002 TAG ftf meeting

Vancouver, British Columbia (CA)

Nearby: agenda | issues list | www-tag archive

All present. Back row in photo from left: Tim Berners-Lee, Norm Walsh, Stuart Williams (co-Chair), Dan Connolly, Chris Lilley, Roy Fielding, David Orchard. Kneeling from left: Paul Cotton, Tim Bray, Ian Jacobs (Scribe).

TAG group photo in Vancouver

Accepted 16 Sep minutes. Accepted status of completed action items in the agenda.


Editor's Note: The archived IRC logs that we used to compile these minutes are broken and incomplete due to connectivity outages at the meeting. These minutes were pieced together from the scribe's local notes as well as from information from the IRC logs.

24 September

The TAG extends hearty thanks to Tim Bray (Antarctica) and Philip Mansfield (Schema Software) for hosting and providing logistical support for this meeting!

PROPOSED: to thank HFN for help on deeplinking.
SW: I'd like to thank Henrik F. Nielsen for his help on the analysis of the Danish linking case.thank Henrik F. Nielsen for his help on the analysis of the Danish linking case.
Action PC: Ask Henrik to forward email to www-tag; thank him on behalf of TAG.(Done)

Agenda review

PC: Will we do enough work at this ftf to revise the document?
IJ: My next priority is to get UAAG 1.0 to PR. So I need a little time to get that done before turning back to arch doc.: But still expect to be able to have a second draft by mid-October (read: before the AC meeting in any case).

How is the TAG doing generally?

CL: Moving more slowly than I expected, but we are hitting the hard questions all at once. But in the last few months we have picked up speed.

TB: I'm pretty pleased by and large. I like the progress of the architecture document. I was very pleased with our intervention on the SOAP question. In an ideal world, we would go faster, but we're all busy. I think that at some point our work will slow down, in fact.

SW: I'm in a cycle of looking just one week in advance; would like to be looking further.
DC: I've not found any teleconf a waste of my time.
PC: I appreciate the agenda being available on Thursday before meeting.
TB: The quality of the phone service is not good.
[Discussion of voice over IP...]
PC: One issue is cell phone quality and being on the move.
RF: Tuesday would be better for me (to get work in my head)
PC: We have not done much to coordinate work on arch outside of w3c.
DO: We don't do enough forward-looking work.
TBL: It would be useful to look forward (e.g., think about sem web and web services), but I find it difficult to do without a stronger foundation.
PC: We are supposed to report AC in Nov 2002 about formation of the TAG. We haven't done that at all.
SW: I will schedule time for this.
Action IJ, SW: Compile list of process questions AB postponed so that first TAG could answer.
SW: So people sound relatively happy with the way we're working.
RF: I'd prefer it if we did more collaborative authoring.: Each of us writing what we think, connected in a single document, in a way that's manageable. But not wiki.: I want to be able to write into the document.
TB: The conventional process is that the editor records hammered out consensus.
DC: Not in all groups.
TBL: There are problems like my desire to s/resource/thing/g. At times I copy the latest draft, and annotate class="tim" for what I've done.
DC: XHTML editing with CVS is good enough for me.
TBL: W3C annotation service lets you thread comments; but you can't print a harmonized version.
TB: I like the current process of issues list, resolutions, series of critiques, and editor incorporates. I find the current system of issues list fairly time-efficient.
DC: Issues for me are very tied to the document.
TB: We have web services arch doc coming along. Is there any similar milestone in the sem web activity, for the TAG to look at?
DC: There's been talk about a document about how sem web work fits together. I could tell the Semantic Web CG we want that.
PC: I think it would be great to have a TAG town hall at XML2002 (in Baltimore)
grumble... can't copy/paste date/city from conference home page.
PC's info on town hall (Member-only)

SW: Who expects to be at conf: PC, TB, CL, NW, DO

" - DC: Need to be able to carry out mundane tasks on the Web," -- yours truly, 7Jan2002, at the 1st tag telcon
PC: In two weeks I'm giving a talk in Australia on the TAG.
TB: I gave my first TAG talk last week here in Vancouver (at the Vancouver XML Developers' Association). Nobody went to sleep (e.g., on why URIs matter).

TAG election end of 2002


IJ: I have been working on TAG election schedule; terms to start 1 Feb.: Any objections to extending terms one month? [None]

Meeting planning (Nov 2002, Feb 2003, Tech Plenary, WWW2003)


TB: Our next (one-day) ftf meeting 18 Nov.

RF: My regrets for that meeting (Apachecon)
Action IJ: Find out more admin details about TAG ftf meeting in Nov.
On reporting to the AC:
  1. Expect 30-min slot for the TAG. Who is reporter?
  2. Top three issues?
PC: We should seed discussion with recently resolved issues, issues that have received a lot of discussion, or unresolved issues.: We haven't had much feedback from AC.
IJ: I send summaries, but haven't heard back. It may be that tech v. process may be an issue.
PC: We may need AC reps to ping people in their company with TAG summaries.
TB: I fear that people won't pay more attention to our summaries until we hit last call.
PC: When TAG pays attention to an issue, relevant WGs react.
TBL: My sense about "how we are working" is that we're doing pretty well: we are reporting, getting input, and we are listening.
SW: How are we going to prepare for AC meeting and tech plenary 2003?
IJ: Does the TAG plan to meet ftf during all-WG meeting 3-7 March in Boston?
PC: I can't; other WG meetings.
DO, NW: Same position.
PC: What if we ask Steve Bratt for a slot at the AC meeting to go over the arch document?
DO: +1
CL: How different from the reporting slot?
PC: We could shrink the reporting segment and make the discussion slot longer.
TBL, CL: +1
IJ: What's connection with TBL's Director's perspective talk? Should that be less technical and move tech info to the TAG's slot?
Resolved: Request a slot at AC meeting for arch doc review, distinct from short TAG report.
- Action IJ: Send email to SteveB requesting slot at AC meeting for arch discussion, distinct from TAG reporting slot.
PC: If the AB is going to shorten its report (and have a separate item on the process doc), that the AB and TAG report could be squeezed in a smaller slot.
Action IJ: Ask the AB if they agree to following:
  1. One shared slot for general TAG/AB report
  2. One slot for AB to present on revised Process Doc
  3. One slot for TAG to present on Arch Doc.

.Resolved: No ftf meeting during tech plenary week.

Action IJ: Report to admin folks.
SW: New TAG will be starting 1 Feb.
NW: Good reason to have ftf mtg early in February.
DC: I'm fine in Feb.
SW: I suggest Boston in Feb, then Europe in the Spring.
Proposed: 6-7 Feb in Boston.
Feb 6 and 7 work for me
[Some suggestions to have weekend meeting around tech plenary.]
PC: I suggest having joint meeting with old/new tag folks if Feb mtg takes place.
Action IJ: Arrange local, meeting in Feb 2003.
Resolved: to meet 6-7 Feb 2003 in BOS (or a nicer venue nearby).
Action SW: Take top 3 issues for AC meeting to the list.
hmm... we all said the tech plenary was our most important audience, then didn't deal with it at all. 1/2 ;-)
IJ: I think there will be a TAG report there (or should be).: Other questions from PC:
  1. Face-to-face alongside WWW2003 in Budapest?
  2. July 2003 on US West Coast (aligned with AB ftf meeting)?

Issue httpRange-14: What is the range of the HTTP dereference function?

See httpRange-14.

TB: What are the bounds of the issue?
SW: I think that Tim's position on what an HTTP URI refers to is driven by the principle that a URI should consistently identify one thing.
TBL: I haven't seen a way proposed by anyone that allows me to do what I want to do in the Sem Web.
CL: I put forward a proposal:

TimBL presents his arguments using illustration of a car (also available as SVG, but less up-to-date). Thumbnail version:

Illustration of car as resource

See TB statements on contradiction between unambiguity and change.
TB: I think DC and I agreed that ambiguity is harmful and should be avoided. Some people will write assertions in RDF that conflict. This will happen though. It should be avoided.
IJ: I hear discussion (rift) between what humans do and what machines do.
RF: People link to things based on information they get, not location.
TBL: Concerns about human vagueness are absolutely right. But for me the sem web needs to have different identifiers for Roy and for Roy's home page.
[General agreement]
CL: The arch should cope with the occasional 404.
CL: Today we have lots of experience with URIs to Roy's home page, but not to Roy.
CL: I don't want the mere "#" to totally change what the URI points to.
RF: I agree.
CL: I don't want meaning to hang on the "#".
Chris: I don't want foo and foo#bar to be quite different things
CL: You know identity in some cases by inspection. But you don't know the meaning of resource by looking at the URI.
TBL: Identify sometimes a (unwritten) contract, sometimes a set of representations.
TBL shows model where two image formats (PNG, JPEG) are representations of a resource, but are also resources in their own right.
agenda + Can two different URIs identify the same resource? [CL seems to think not. I think so]
(TBL: Most people don't do content negotiation, or other negotiations. )
TBL: Now take the case of the car. In RDF, I talk about the car, pictures of the car, owner of the car.
[The real car and the real owner.]
TBL: Semantic Web needs to allow people to distinguish between "the real car" and a home page about the car.
DC: If you choose to use the same identifier for both car and web page, you've said the car is a web page.
TBL: DC says that you don't know that it's not a web page until someone gives you more information.
DC: You can choose different identifiers for car and page, you can. You can also choose the same, but that's ill-advised.
CL: The URI doesn't make the subject a car. It's the assertion that "This URI designates a car."
TBL: Whatever the abstract thing is, it's the Subject of the document (the resource "car")
CL: How is the car a resource? Can I get variants of it?
TBL: It's not a "network information object". If you read the RDF spec (or related), in many cases you don't have a representation available (example of Pantone colors not on the Web, but identifiable). In some cases, it will be interesting to dereference the URI, but in some cases you won't have to or want to dereference a URI.
CL: Do I have to dereference the URI to get back RDF and interpret the frag id in a particular way.
TBL: I may send you RDF in an email message saying that </foo/sale#it> a w:car. If I send you this, you'll know that it's a car (provided you believe me).
RF: You can replace every identifier in that email with another HTTP URI. You are assuming that because you have an identifier, you are doing a GET on the resource. If I give you a resource and you can't GET it, why do you interpret that it's not a document?
TBL: We don't have a way in HTTP of distinguishing car from document. When I deref something, how can I know whether I am talking about a car or a document? We could extend HTTP...
DC: What breaks if you take the "#" out?
TBL: I deref the URI and I get a representation back (a Web page). I need to be able to talk about the car, pages about the car, and relationships among representations. The concept of a Web page in its own right is very important (and has age, creator, author) that are independent of ....
DC: No. It falls apart in the Moby Dick example (who wrote the book? who wrote the page?)
SW: What if you replace http: with http://vin.org/ ?
TB: You get a representation of the resource.
[TBL goes through another example...]
RF: Dublin Core dc:create is specifically for documents. Don't make metadata assertions about both the car and the web page. I hear mixing of methods and resource. You can identify pages and other concepts with different URIs.
PC: I hear underlying problem is that TBL wants to refer to something that's not on the Web. And he has a particular (recognizable) syntax for doing so.
Where 'now' is defined to be a non-dereferencable protocol
PC: Seems like TBL wants a separate syntax for identifying a class of objects or their physical instantiation that has nothing to do with the Web. Tim thinks HTTP URIs are already used to represent something else.
NW: Earlier we said that people could make conflicting assertions (and that errors arise). It seems to me that TBL has a particular system where documents do not equal cars. Fine. Your system will produce an error when this (silly) thing is done. I could have a system with a different set of axioms. Where is the problem? My system will or will not contain contradictions. They may be different contradictions than in your system. I think TBL's constraint is not a Web arch principle.
[TB presents]
"/car" represents the real car.
dc:type "car"
TB: By the way, some descriptive text of car available at /car.html. That document is also a representation of the resource that is a car. I can build a functional system that doesn't get me caught in loops. You can have URIs for different entities; if there's confusion that's bad (so we shouldn't do that. TB: I would propose that in the arch doc we say (conflating principles 2 and 7):
  1. Ambiguity in the relationship between URIs and resources is damaging (both in conventional Web usage and the semantic Web).
TB: I think we don't need consensus around what http URIs refer to. But I think we can skate around.
TBL: What should response code be when GET on "/car"
TB: Should be 200. I can send back a representation of the resource. I could also choose not to send a representation.
DC: Today, Web servers send back resource location and a representation of car.html
TB: It's reasonable to say "/car is red" but not "/car.html is red". The representation of the car can be a resource in its own right if you want to make assertions about it.

There is general support for TB's proposed conflation of principles 2 and 7.

TBL: I'm trying to decide whether that's good enough.
TB: Next issue - what, if anything, do we say about the range of particular URI schemes. Maybe it's the role of the sem web activity to say that "the premise of the sem web is that HTTP URIs identify documents (even though there are counter examples)".
DC: I'm mostly supportive of TB. I have some lingering concerns. I think there are confusions around terms:
  1. Resource
  2. "Resource representation" / "Digital artifact" / "Entity" (in HTTP sense) / "Instance"

    [RF doesn't like "instance" here since not really an instance (in the sense of instance of a class)]

  3. cyc:conceptualWork is something "in-between".
DC: To me, a resource is anything you can talk about.
[TB: "anything with identity"]
DC: Let's use "conceptualWork" (or something else) to refer to things that you can get bits for.
IJ: Can you give me a better sense of the fidelity expected for a conceptual work?
DC: It's fuzzy. Some resources are directly observable. We are advocating that IETF use HTTP URIs for media type names. What URI should be used for "text/plain"?.
TBL: What should the return code be? I think that HTTP may be a way out of this.
[CL presents]
CL Axiom: You can never get a resource, just a representation. In some cases (e.g., only one representation), they are pretty close.
[CL talks about different meanings of "creationDate" in car scenario - you need to say exactly what you mean among several possible creation dates.]
DC: Somebody owns pic. Are you disputing that the guy who owns it can provide a creation date? If I own the resource, I can say when the resource was created.
CL Summarizing:
  1. I assert that you cannot GET resources, only representations.
  2. Therefore creation dates only refer to representations.
  3. Conflating the two parts of the model will create a bad model.
  4. Put the efficiency in the implementation, not the model.
TBL: If I get back same-looking representation for both "car" and "car.html"... In most of the Web, I am talking about pictures, not cars. People understand that I'm talking about the picture. Need to distinguish between whether the picture is black and white, or the airplane is black in white.
TB: I suggest procedurally that we:
  1. For next arch doc: Change principles 2 and 7 to be "Ambiguity in the relationship between URIs and resources is harmful for humans and machines." Two instances of ambiguity are (1) lack of resources and (2) confusion about what is identified. Such ambiguity easily arises; should be avoided. This can be done in practice. Add some examples.
  2. We don't need to say what range of HTTP URIs is for arch doc.
TBL: I think that's reasonable, but doesn't address issue 14.
Resolved: Accept TB's proposal for revised principle.
TB: I propose that httpRange-14 be de-prioritized. Two reasons (1) no consensus (2) I don't think it affects the arch doc. I would be amenable to close this issue with no action.
DC: I agree with TB that httpRange-14 can be closed with no impact on the arch doc.
RF: When you access a resource for today's weather in Vancouver, and you get back info that says "it's sunny", how do you know that it doesn't mean "it's sunny everyday in Vancouver." When you access a resource, you need to be able to make assertions about the resource and also representations of the resource.
Resolved: "Defer" httpRange-14 with no action. Objection: TBL.
It's essential to me that, in the summary of the issues, this version of 'closed' is distinguishable from things like issue 7, which we actually addressed in substance.
I didn't propose saying this issue was "closed" but rather "decided", with disposition "deferred". We always have decisions in the end. In this case, the decision is to do nothing.


Issue namespaceDocument-8: What should a "namespace document" look like?

See namespaceDocument-8.

TB: Namespaces are just names. There is angst in the community about dereferencing these URIs. It's arguable that it's an architectural issue or that it's not.
RF: All HTTP collections ("directories") are namespaces...
TB: I published theses regarding namespaceDocument-8.Two use cases at least (1) schema-like info (2) assertions in sem web that can be used for inferences. Some pushback about RDDL. We reformulated in RDF. Some options:
  1. We could say that this is not an architectural issue. Maybe XML Core could take this up.
  2. We could stop with a principle or finding that it's good practice to put something at the end of a namespace URI, with use case scenarios.
  3. We could go so far as to recommend what should be found there.
TB: If you don't do anything, some bad things can happen - either human-readable or machine-readable; and I don't think coneg helps you out. Media type is not sufficient granularity. HTML has three DTDs...
but all have the same media type
DC: I think content negotiation solves the problem in TB's case.
TBL proposal: Establish the convention of putting an xhtml doc with embedded RDF having (1) made a statement that when RDF is embedded in HTML, it's valid for processors [and change schema accordingly].
DO: Who would take the spec to Recommendation?
TBL: The piece about putting RDF anywhere in HTML is a generically useful action. We'd also need to say that RDF parsers can ignore HTML parts. The question who says about who ignores what is interesting; not quite html wg or rdf core.
PC: I don't think the TAG should do this work.
TB: Notion of embedding RDF is easy. RDDL comes with a pre-cooked vocabulary (nature and purpose, which some predefined purposes). The task would involve (1) statement of embedding policy (2) documenting precooked vocabulary.
TB: I think you can't get around writing a specification.
PC: I think the TAG needs to ask the Membership whether they want this done.
TB: I would be willing to change RDDL.
PC: Delegating this to someone (e.g., XML Core) may be the way to go. I'd personally prefer that this work be done by a technical WG.
RF: This doesn't change the arch doc (since "SHOULD"). Let someone go off and design the format.
PC: I want to be sure that I'm not FORCED to dereference.
RF: There are two separate questions: can be dereferenced v. must be dereferenced.
DO: We should ask TB and Jonathan Borden to update the spec, and give that work to the XML Core WG; if they don't want to work on this we should find some other group. I would like to do this as a more forward-looking step.
DC: Is it ok to delete "Issue 8" from its placeholder location in the arch document with no harm? The RDF Model and Syntax Recommendation in 1998 has an appendix for including RDF in html docs.
TBL: The proposed solution to this issue, touches on the issue of language mixing (mixedNamespaceMeaning-13). Content negotiation would work, but I would have a problem with coneg when the documents you get back talk about different things.
[I don't think it's a "problem" that WGs aren't dealing with namespace mixing; if the solution were apparent and being ignored, that would be a problem. But I don't think a solution is apparent.]
RF: If we are making specific principles of w3c groups, or others (e.g., dereferencing namespaces), these should be called out separate from web architecture.
TBL: I propose finding that documents should be self-describing using the Web. Should we have a separate sem web arch group?
RF: I think you should have a separate sem web description.
[RF on multiple architectures...depending on tasks.]
CL: On mixed namespace issue - if rdf is root element, does that mean something different than if html element is root?
TB proposal:
  1. TB could take an action to recast RDDL in RDF and turn it into a W3C Note, for review by the TAG.
SW Summarizing where we have gotten:
  1. TB volunteers to recast RDDL in RDF and publish at Note.
  2. Proposal from DC to strike line in arch doc pointing to issue 8
DC: The HTML WG needs to be party to this agreement.
TB: Right, xhtml modularization designed to accommodate this.
DC: When technologies first deployed, original WG usually consulted to see if done the right way. Please consider charter (or portion) for what a WG would have to do.
RF: If we have lots of RDDL docs at ends of namespace URIs, what's the problem?
DC: They don't validate.
DO: I will write up the charter bits for what a WG should do.
Action TB: Revise the RDDL document to use RDF rather than XLink. Goal of publication as W3C Note.
DO: Should the namespaces spec change?
DC: Yes, it should.
PC: I think that DO has a good point. We could get the Core WG's attention by making a last call comment; namespaces 1.1 is currently in last call.
CL: Namespaces 1.1 only applies to xml 1.1 (not xml 1.0).
From XML Namespaces 1.1: "this revision is being tied to the 1.1 revision of XML itself"
DO: We'd like to see a change to namespaces 1.1 along the lines of (1) add "should" be able to dereference for this type of document and (2) the TAG will work on what type of document that is.
NW: Won't this delay Core WG indefinitely?
DC: I'd be willing to ask for a delay of 2 months.
(namespaces WD went out 3 Apr 2002)
TB: XML Core WG is not going to be happy with our request to make this change.
DO: "It is not a goal that it be directly usable for retrieval of a schema (if any exists)." -- http://www.w3.org/TR/2002/WD-xml-names11-20020905/
SW: What is the positive goal?
PC: I have concerns that this proposed change is out of the scope of what they agreed to do.
CL: I think that a last call comment for namespaces 1.1 will not achieve what we want.
TB: I disagree. People will start doing it.
NW: I agree, the MUST in the last call doc won't be a problem.
[the positive goal from the Arch Doc is: "Owners of important resources (for example, Internet protocol parameters) SHOULD make available representations that describe the nature and purpose of those resources."]
PC Proposal:
  1. We do what TB says - we solicit creation of a (RDDL) Note.
  2. We actively figure out how to put into the w3c work plan.
NW, TBL: Let's ask core wg to do this for namespaces 1.2
DC: We should get this on the public record, and indicate we realize not quite right for 1.1.
[this = relationship between Namespace revisions and TAG issues, e.g. #8]
DO: So should this be in 1.1 or later?
TBL: I think it's legitimate to leave core wg to leave 1.1 as is.
Resolved: Draft a letter to the core wg as part of the last call process saying: (1) this has been a TAG issue, (2) there is substantial sentiment towards providing some best practice about what a namespaces URI should point to, that (3) that the intention of the TAG is to publish a W3C Note with info about what to find at end of namespace URI and that (4) while that it may not be appropriate for namespaces 1.1, it's important to get discussion going in the public space.
TB: I think for us to let last call go without a stake in the ground is a mistake. But make clear that it's not a directive from on high.
Action TB: send a draft email to tag@w3.org.

Issue contentPresentation-26: Separation of semantic and presentational markup, to the extent possible, is architecturally sound.

See issue contentPresentation-26
TB Proposal: In chapter 3, make a best practice statement saying that there are significant benefits to the separation of content from presentation in the Web spec, to the extent possible.
[does the WAI spec already say this somewhere?]

[IJ: Yes, in XAG 1.0: 2.2 Separate presentation properties using stylesheet technology/styling mechanisms.]

CL: I think this should be a principle, not a best practice note.
TB: I have encountered many applications where you can't make the separation (though I think it's a good idea generally to do this). It's clearly not a MUST to me; but clearly a SHOULD.
NW: I agree with TB.
Action CL: Draft text on this principle of separation of content and presentation.
[I'm hoping for specific examples. XSL-FO, "multimodal publishing", mobile, ...]

Issue xlinkScope-23: What is the scope of using XLink?

See issue xlinkScope-23.

[DC goes through various groups that used xlink and those that did not.]
DC: NW said that "Whatever the poison, I can swallow the pill; just give me ONE pill." In the end, we felt that this may just be a marketing issue.
IJ: I think there is agreement that there is benefit to reuse, but we don't perceive today buy-in. That was part of our discussion yesterday.
[CL on HTML WG history of use of xlink]
Seebackground from Mimasa(Member-only).
CL: The SVG WG thought there would be support for xlink, but support is waning. I see that HLink is entirely specific to xhtml. We should either deprecate Xlink or do whatever, but I agree with NW that we need one solution. Not sure what technology is the right one, but I would like to see one solution.
[General agreement that in any case HLink needs fixing.]
TB: Given that xlink is designed for user interface application of hypertext, if browser vendors had implemented xlink, people would have picked it up. The fact that the HTML WG has decided not to go towards xlink is a bad sign. HLink as posited is bogus. Not sure why it needs to exist. Not sure of benefit to retroactively design something that pretty much works. I think HLink has pieces that don't work (e.g., longdesc in three languages. Given my druthers, at the moment, for UI applications of hypertext, xlink is a substantially superior design base. Why has nobody proposed user-definable multi-ended links to html? If they had done that, what alternative would they have suggested for doing it?
TB summarizing: For UI-oriented applications of xml, xlink is basically a sound design. If it's not to be used, a sound technical reason must be given why. In any case, HLink needs a lot of work.
RF: XLink is not backwards compatible.
TB: The XLink WG had this in their charter and didn't deliver on this.But the xlink wg wasn't convinced of the benefits.
DC: But it was in the xlink wg charter.
TB: We didn't deliver on it, but not through oversight. We didn't want to recreate architectural forms. You had attributes on attributes....
CL: I note that Mozilla supports simple xlinks (but not extended). See Mozilla claim and doczilla xlink demos (and other demos).

[DC: hmmm... demo doesn't work in the use case I'm interested in: http://www.w3.org/2000/08/w3c-synd/home.rss]
[DC: Demo works in Galeon, which is build from Gecko.]

TBL: Can HLink be phrased as a constraint on xlink? Different ways: namespace or app info. [Scribe uncertain about this statement.]
TBL: We could ask HTML WG to reformulate HLink in terms of XLink.
PC: We should ensure when our issues are tied to documents (and their schedules). The xlink wg was originally asked to map its work back onto html. I think we need to make a strong statement about whether we think these two technologies should evolve in parallel, to see which one wins.
DO: Design goal of xlink was 'link detection at run-time'. Another way to do this is at schema evaluation time. "Design time v. run time". Maybe both needs exist (HLink requirements might be addressed with design-time solution). Maybe this is a case where "only one solution" is not applicable.
NW: With xlink, the only difference from html was that you had to say xlink:href instead of href. I have been waiting for years to get a linking solution for DocBook. I don't want to reinvent things. I want just one solution. XLink gives you both design time and run-time solution.
DC: Two points:
  1. I was disappointed when xlink came out that they didn't bother to make the html syntax workable. But that time has mostly passed.
  2. Since yesterday, this has appeared to me as a marketing issue. XLink seems to be a solution to 80% of user issues. Should the TAG do some marketing here?
DC: I'm leaning towards encouraging re-use at this point.
TB: If we think that the HLink approach has validity and should be pursued further, I think we should look at ISO Architectural Forms work ("This attribute is one of those..."). Given that HLink does kind of the same thing, someone should take an action to talk to the HTML WG to find out if this has been researched.
TB, improvising some proposals:
  1. Declare this issue closed. XLink is available and can be used. And that's all.
  2. We could assert that the TAG thinks there are substantial benefits to having one place that explains how to do hypertext markup for doing user interface-oriented applications. But not say which one.
  3. We could ask W3C to deprecate XLink since not catching on.
  4. We could say that we feel that HLink as it stands is not a productive direction for a W3C WG and needs to be substantially revised or something ....
CL: Summarizes as (1) everyone use Xlink (2) everyone use HLink (3) do what you want.
RF: Another option: Fix XLink. If XLInk is going to be the one solution, it needs to accept requirements from others.
TBL: Do you mean in feature requirements?
CL: Syntax requirements not backwards compatibility.
"XLink must support HTML 4.0 linking constructs." -- http://www.w3.org/TR/1999/NOTE-xlink-req-19990224/
TB: Writing a change to xlink to add some more markup to the xlink namespace to do the hlink-style attribute remapping; with a statement that this should only be used for backwards compatibility. But I think the HTML WG would not want xlink namespaces in their html.
TBL: There's a larger battle here about whether people believe in namespaces at all.
CL: Tantek Celik thinks there should be one W3C namespace. [That makes his job easier when he has to implement W3C specs] There are a number of html link features that would break xlink if tried to be incorporated (e.g., hreflang).
[Marshall rose's DTD for Internet drafts puts human text in attrs. bummer, that.]
CL: What would drive xlink if there were implementations of the more interesting things.
TB: Maybe the world doesn't care about multi-end hyperlinks.
TBL: Are we trying to clean up specs so that implementing them will require less code (or less application-specific code)?
CL: Is the market for these components only W3C specs or other xml vocabularies?
TB: XBRL is an example that uses components.
<wg:requirement wg:for="XML 2.0 " wg:needed=>XML content in <s>attributes</s></ wg:introduced="tag">
NW: HLink doesn't require you to type the colon.
SW summarizing:
  1. XLink exists, is being used, has been implemented in at least Mozilla
  2. Covers most of what people want it to cover...........[SW cut off...]
TB: The HTML WG will come back for the 100th time and say "XLink fails the backwards compatibility requirement." What do we say to this "Go home? We will recommend that this be fixed this if you agree to use it?"
TBL: I am not sure how many of the multi-end features have been implemented. Alternative proposal:
  1. Some parts of XLink have been implemented.
  2. XLink is a bit more powerful, gives linking a namespace.
  3. A possible stance would be to abandon (through lack of interest) the multi-end links, even though defined.
  4. We suggest that xlink simple links be used for simple links.
Reviewing article "XLink: Who Cares?", 13 March 2002 by Bob DuCharme:

"The only project with more than three "yes" entries in the table's eight columns is Fujitsu's XLiP, the "XLink Processor." Its XLink engine advertises support for XLink simple and extended links, including support for locator, resource, and arc elements. The engine itself isn't available, but..."

DO: Generic linking doesn't solve any particular problem really well. No killer app to make it take off.
NW: Not sure that removing multi-end parts of xlink would help us solve the current problem.
RF: There's still a missing bit of xlink that doesn't adapt to existing grammars.The missing bit: if you have an existing grammar with defined attributes that refer to hypertext link relationships, there's no way to say in xlink "By the way, this attribute is a link".
NW: Even if xlink provided that feature, you'd still have to revise the DTD/schema.
TBL: But you wouldn't have to change the instances. You would retroactively change the schema. Yes, I would change the schema without changing the instance.
TB: Point of information "eXtensible Business Reporting Language" (xbrl) uses extended links (see section 5.3.2)
[[[Extensible Business Reporting Language (XBRL) 2.0 Specification]]]-- XBRL Draft Specification - 2001-11-14http://www.xbrl.org/TR/2001/XBRL-2001-12-14.htmWed, 27 Feb 2002 22:33:33 GMT
TB proposal: XLink is designed for precooked xml markup for describing hyperlinks in user interface-oriented applications.
TBL: I note that there's a dependency here on xml namespaces.
RF: And this is for "new" doc formats.
TB: I would like to say that if html wg adds multi-end links later, to use the baked part of xlink.
DC: If what TB and TBL said is true, our response to HLink spec should be "no".
TB: So HTML WG SHOULD use XLink for XHTML 2.0 unless there is substantial technical reason why not.
[Some support for that]
Action NW: Draft an email (for TAG review) suggesting to the HTML WG that XHTML 2.0 should use XLink for hyperlink constructs, or provide a technical explanation why that's not a good design decision.
DC: We are not asking for explanation at this point. TAG simply suggests that the HTML WG SHOULD use XLink. On the basis that fewer technologies is better for the world.
No dissent to suggesting to HTML WG to use XLink in XHTML 2.0.

rdfmsQnameUriMapping-6: Algorithm for creating a URI from a QName?

See rdfmsQnameUriMapping-6

Original question from Jonathan Borden:

It seems to me that the RDFCore and XMLSchema WGs (at the very least) ought to develop a common, reasonably acceptable convention as to the mapping between QNames and URIs. Perhaps this is an issue that the TAG ought to consider (because it is a really basic architectural issue)."

TB: RDF names things using QNames, and specifies a way to turn qnames to URI (refs). Other places use QNames to identify things, and in those places, no agreed way to turn QName into URI ref. This is a perceived problem.
TB: We could say:
  1. That's ok. In some cases it's ok to name things with two-part names (local part + URI ref)
  2. No, if you are to name things with QNames, you'd better provide a rule for building URI refs.
  3. Not only do you have to do this, here's how to do this. (And I think concatenation is the only reasonable way).
DC: Specific case that came up, something like ~~~~~~~XMLSchema#decimal. When you write XML Schemas, it shows up something like xsi:type="decimal", and I think you can say something like "dt:decimal" where dt is xmlns:dt="~~~~~~~XMLSchema" [no hash].
DC: Meanwhile, in RDF-land, people see the URI ref "XMLSChema#decimal" and are happy. In RDF you can write <dts:decimal>10</>, binding :dts="~~~~~~~~~~XMLSchema#" [with hash]
DC: People unhappy to see hash in RDF context, and no hash in schema context. XML Schema spec introduces machinery for other data types, with a mechanism for qnames but not URI refs.
  1. The relevant principle is that all important resources should have URI refs. That answers the question about whether there should be URI refs: yes, they should not be tuples.
  2. Possible solution to this is: here's the algorithm for constructing the URI ref from the namespace URI: If it ends in an alphanumeric character , then add # before concatenating the name, otherwise just concatenate the name to the namespace URI.
CL: There's a problem with that if the character is escaped.
DC: I agree with RF that it's nearly what RF said.
NW: I think that the schema wg is actively working on this issue.
PC: Right. The difficult problem is that some schema types are local; not visible outside schema.
DC: Those don't need URIs.
NW: I think the schema wg should have a chance to get the first wd out.
DC: All the ideas I've seen so far would make the RDF WG happy.
TBL: There's a problem of same qname used as both element and attribute name in same context. Is there a problem that the RDF WG has with mere concatenation?
SW: RDF labels nodes with URI refs, and uses a Qnames as a means to encode URI Refs. ie RDF is more concerned with the URIref->Qname->URIRef mapping and less concerned with a Qname->URIRef->Qname mapping.
DC: If you process RDF with xslt, the xslt only cares about the qname. There are RDF users who care that the QName mapping works both ways. So, even for some RDF cases, it qnames matter.
RF: Element/attributes are not in same namespace; it's hierarchical (element.attribute).
DC: The schema wg is chartered to do this. We could send the Schema WG a note saying "We have this issue; you are chartered to so this; please notify us when done."
TB: At the moment, the only observed place where this is biting is in XML Schema. Is there a larger problem that's lurking here (where qnames are being thrown around)? I'm not aware of other examples.
Action DC: Write to Schema WG to say that TAG is interested in progress on this issue.
SW: Please copy Jonathan Borden and Brian McBride to ensure they are aware.

September 25

All present except Paul Cotton.

Architecture Document

Reference draft is 30 Aug 2002 draft.

RF: Looking at the arch doc, I had to figure out what people meant by architectural principles. Do we mean general principles like simplicity, or do we mean constraints that we had imposed?
DanC: It is in fact discussed in section 1.3:

"This document focuses on architectural principles specific to or fundamental to the Web. It does not address general principles of design, which are also important to the success of the Web. Indeed, behind many of the principles of Web Architecture lie these and other principles such as minimal constraint (fewer rules makes the system more flexible), modularity, minimum redundancy, extensibility, simplicity, and robustness."

[DanC: Also in section 1.4.]
TB: People bandy the word "architecture" around all the time and what they usually mean is the major design decisions. A general decision across the board.
RF: There is no physical dividing line. My idea of software architecture is to focus on one aspect of the system. You don't focus on more than one at once. So I wanted to discuss the principle, not the constraints. Principles are things that guide our decisions. Constraints are particular decisions based on those principles.
TBL: I think there has been confusion on the list about what architecture is. Our job is to list the constraints.
RF: Constraints without motivation is a recipe for argument.
RF: Our job is to list the constraints and the argument behind it. We can negotiate with WGs too.
DO: My interpretation is broader. You talk about it applying to "a particular phase". I look at it as looking at all the phases.
RF: Phases form a time scale. You can look at one level at a time. To look at all at once is possible but complicated.
RF: Think in 10-year time scale. I don't know how to contribute to the document as we are proceeding.
RF: I have a problem that we are addressing everything at once
TB: Yes, I agree that what's in the boxes are constraints.
TB: I agree we can look at different views.
DO: Is that what you mean?
RF: All the constraints are always applicable.
DO: Yes ... 4+1 views of architecture from Rational.
TB: Our current constraints (see section 1.4) are long-term.
TBL, CL: This is too abstract for me.
CL: There's a marketing issue here if you call them "constraints" or "restrictions".
[Ian will scribe]
I found what RF was saying too abstract to understand... too vague.
RF: The principles that TBL has about "unambiguous URIs" is not a constraint (we can't force it). But we can say that there's a principle that if you don't do this, bad things will happen.
TBL: The TAG is not defining components. The TAG is documenting global constraints. We may need to fill gaps, but our job is not to plan for the next 20 years.
DO: Chartering of WGs is not architecture.
TBL: I think that we should accept that there are different forms of architecture. The Web Services Architecture WG can't define general constraints. They don't glob into domains.
RF: I think these are just different abstraction levels. But it's still one architecture, and still one definition of architecture.
DC: There was a block-diagram with clients in servers when I got involved in the Web... The document doesn't have a definition of architecture and I don't see any pain in that.
IJ: Functionally, it would be good to have more motivation in the document.
RF: Describe the global requirements on the system, such as
DO: Yes, functional requirements of the system. And some non-functional requirements (e.g., scalability, robust error handling, minimal interactions)
CL: Some of what we have today is issue-driven. I think there would be little disagreement about areas that RF is describing. We've focused on what people disagree on.
DC: Yes, I'd like to see more motivation; principles should be conclusions not starts of arguments.
TBL: Perhaps we do talk about modularity.....when we've said xhtml ought to use xlink. On the topic of functional requirements: that makes sense in a project that has an end (e.g., building a coffee machine). However, with the Web, new pieces come along (e.g., voice browsing). We don't have the requirement of defining the Web in a manner that will terminate. I like the constraint approach (backed with principles) is that we can make the fewest number of constraints so that the Web continues to work. When the next wacky thing comes along, still we will want to preserve the existing Web.
RF: No need to start again. Just give direction. If I could feed Ian text on how to describe these as constraints and principles, I would be able to contribute more.
TB: Sounds like we've all bought into the notion that we are writing constraints.
DC: Some of those we want to keep are not constraints. E.g., "Representation retrieval is safe" is not a constraint.
TBL: There is a balance: there are things like "persistence" at that level, but we only put "persistence" there since it's been a problem. I agree that this document is not the "complete" Web architecture book. The list is a mix of high-level and low-level bits.
RF: By confusing principles and constraints, we are creating arguments where we don't need them. We don't need to constrain the architecture, but we need to motivate the principle. It's a principle that persistence is necessary since if you don't do it it's damaging. An example -
IJ: What's the difference between the agent-less principles and those that include SHOULD/MUST/MAY? How do agent-less statements fit into RF's model? Are most of the constraints agent-less?
RF: Generally when you specify a constraint it's targeted.
TBL: I'm happy with the document, but it needs some philosophy. When you use the Internet, you sign on to the Internet protocols. You sign on to the meaning of specs. It's worth making the point that we work with specifications.
TB: People need to see assertion of the right thing to do; and where to go to find more information. I'm hearing:
RF: Can we get rid of the title of the principles? Risk of saying inconsistent things.
TB: Pithy identifiers that are not numbers are useful. Maybe we need just short labels. I also suggest getting rid of the numbers.
CL: About "This document does not address architectural design goals covered by targeted W3C specifications". We should say instead: "There's more detail over there." Not that we don't deal with it.
TB: I suggest that we take one test case, and see how RF's model would work.
Action RF: Propose a rewrite of a principle to see if the TAG like that.

Section 3: Formats

[CL comments on text in current draft]
Timbl: the "use XLinks, not IDREFs" is corollary of "use URIs"
[suggestion: "page" for 'presentation object']
IJ: Question - what's the scope of the formats section? Should we limit ourselves to things that are just crucial to making the Web work?
CL: I think it's important to also have information about things other W3C WGs need to know.
TBL: I'm happy when we do this work by defining a little here and a little there.
[One multiple doc formats]
TB: In both opendoc and oda, the failures, as I understand it, were due to the fact that they tried to aim too high. SGML survived, in part, since it doesn't address presentation.
TBL: CSS + XML may work today since CSS is not in SGML.
TB: The reason CSS is great is that it's strongly decoupled from the document format.
RF: "Independent specs for orthogonal problems."
TB: Here's how CL's comments mesh with our discussion on Monday(TAG only). A resource representation (shortened to "representation") consists of metadata and a bag of bits (or, octet sequence). We should explain how "representation" maps to other specs (e.g., HTTP). We can already hang some findings on this statement (e.g., "# Internet Media Type registration, consistency of use")
note to self: remember to come back to 'how much metadata?'. I need it to NOT be open-ended. I can live with 'exactly a mime type'.
TBL: It's an important principle that you need the metadata for the system to work ("competition for suffixes" reflects that this is an ongoing struggle on local systems). The metadata is still there off the Web (in the system registry).
DC: You can represent the content type as ".html" as long as you don't screw up.
TB: Section three should start off with:
  1. Data on web manifests itself as resource representation
  2. A resource representation is metadata + bits
    1. Web metadata...
    2. Web bag of bits...
  3. The following principles apply...
TBL: CL's text doesn't fit into part 2 of that outline.
TB: Once you know by reading the metadata (image/svg+xml), then there are useful things you can say about what goes in the bag of bits.
CL: What about self-describing data? We are saying here that if no metadata, it all breaks.
TBL: We are saying that the meaning of the document depends on the mime type. The way the specs are written is that the interpretation of the bag of bits depends on the mime type. When you use XML, you can use less metadata since lots of the (mixed) content is self-describing (after the initial mime type). We are not saying that external metadata always overrides what's in the document.
TB: Two meta issues to solve (1) how do we organize this section? I think this outline + CL structure addresses issues I'm aware of. Meta-question 2: What are the principles that fit in? Which of what we've written are principles?
Reviewing 3.3 (ideas and issues)
TB: We should say that "When designing new languages, the following criteria [for example] suggest that you use XML: requirement for persistence, requirement for I18N, requirement for clean error-handling."
TBL: I think you should add that: when you need structure, and when there's a MIX of structure and text content.
[Discussion of whether MIME would work in XML]
TB: I think we can agree that the document to say something about XML and when it's desirable: e.g., for I18N-ized content (agreement), supports early detection of errors (agreement), for mix of structure and substantial amounts of text.
DC: It will be cheaper to use XML. "If there is some chance of persistence" since there's lots of redundancy.
CL: Composability.
TB: So it sounds like we have some signposts for when to use XML. [Agreement]
IJ: After you say "when to use xml" what are the principles for using XML (e.g., follow the XML Accessibility Guidelines)?
DC: Whatever specs we endorse, let's endorse individual specs.
TBL: I move that you shouldn't use XML without using XML Namespaces (agreed).
DC: We endorsed xlink with a smaller scope (for UI applications).
TB: We have only agreed to XML + namespaces. We have separately agreed to xlink in some cases.
"# Format designers should use URIs without constraining content providers to particular URI schemes. What does "use" mean? IDREF v. linking - web-wide rather than document-wide references.'
IJ: This is here and not in section 2 since this is about use of URis in formats.
RF: We already agreed to the first sentence (independence of orthogonal specs).
[Discussion of first sentence only.]
DC: I can't agree to "Format designers should use URIs without constraining content providers to particular URI schemes." There are better ways to express this.
TBL, CL: It's worth saying something about using Web-wide, not just document-wide, linking.
DC: Are we going to have a section on Web-izing formats (i.e., taking existing ones and changing them)?
TBL: The principle of information-hiding is contrary to global identifiers....Shall we put in the document something about information hiding/independent design of orthogonal specs? You should should not be able to write an xpath to peek into http headers....
Action TBL: Propose some text on information hiding for the arch document.
Action CL: Redraft section 3, incorporating CL's existing text and TB's structural proposal.

Namespaces, issues namespaceDocument-8, mixedNamespaceMeaning-13

See namespaceDocument-8 and mixedNamespaceMeaning-13.


TB: On namespacesDocument-8, we have an action item. We have an assertion we agreed to yesterday (1) namespaces docs should be there (2) should be something like RDDL.

RF: I don't know, but I think there should be a section on namespaces in the arch doc.
CL: I think this should be a best practice note.
Action NW: Write some text for a section on namespaces (docs at namespace URIs, use of RDDL-like thing).
TB proposal regarding mixedNamespaceMeaning-13: We haven't been able to get consensus around TBL's processing proposal. I think we can say that "Format designers should give serious consideration to, and should document, the effect of embedding content from other namespaces and when embedded in other namespaces."
[Support for this proposal from DC, TBL.]
CL: Example of a policy - if you want to include something to be rendered, include it here. Otherwise, it will be ignored.
TBL: To be more specific, the way you should do this: there should be widely defined classes of things you can embed. E.g., a class of "things that can be embedded here but will only be regarded as a comment".
(Different axes: presentation, semantics, ...) I see the TAG's task of saying in principle, showing how to do it, and including enough rallying points in specs.
TB: XLink is a good example - embed me when you mean for action to be taken.
DC: xlink:href in xslt doesn't mean follow me; it means generate a link (generally).
Resolved: Accept TB's proposal for mixedNamespaceMeaning-13 for formats section.
TBL: We have two conflicting observations here; we probably should have both:
  1. It's useful to say what xml:lang means in a very large number of cases, without too much effort
  2. We also need to allow other specs to use xml:lang in other ways (e.g., xslt outputting it).
TBL: you can't, in xml, resolve the battling attributes problem ("I override this other thing no matter what the other thing says."). You can give an algorithm for interpreting documents to try to resolve this (see the top-down processing model).
TB: I don't see how you can say that, given existing specs.
TBL: You could have a small number of categories (generic) that would work in specs. E.g., XML functions.
TB: Some examples to back proposal (a): XLink, RDF
DC: You can mix lots of RDF vocabularies together.
TBL: RDF solves a lot of these problems - doesn't have the problem of battling namespaces. RDF doesn't have the right to say "you can't write XSLT". RDF has gone further than most specs in saying how to be embedded.

[Lunch. Paul Cotton rejoins meeting.]

[We reviewed Norm Walsh's draft email regarding XLink, which he revised and sent to www-tag; seeXLink email.]

[We reviewed Tim Bray's draft email regarding namespaces, which he revised and sent to www-tag; seeNamespaces email.]

Tech plenary meeting planning


DO: I've been asked to be on the program committee. I'd like substantial TAG participation in that day. Some ideas:

  1. TAG fishbowl. TAG on the stage or having a meeting of some kind.
  2. Technical slot dedicated to a particular area of interest. E.g., REST v. Web services.
hmm... logistics (e.g. audio) of "TAG fishbowl" look unworkable to me.
PC: I could see a model where the TAG runs the tech plenary (and the planning committee would be TAG participants). Some people appreciate the Chair-training process aspects of the day, some do not. People made it clear last year that the day should be largely technical, with TAG driving agenda.
IJ: I think other group input is important.
SW: How much work is it to organize the day?
PC: TBL, DC, and I organized the first tech plenary over the phone. Not much work involved in planning the day. I think the TAG should play a heavy role in the organization of the day.
IJ: The "fishbowl" proposal is tricky for a number of reasons. Among others, experience from the AC meeting is that people don't like to sit there and watch.
DC: There are issues of people being able to hear us in an audience of 150.
PC: Also, we can't be unaffected by presence of 150 people.
TBL: What we could do is re-enact. Use the Socratic method to show people we understand views A and B.
DC: Lightning talks on TAG issues (anybody gets 2 minutes).
TBL: It's good to let people give input on things we haven't discussed.
SW: Does the TAG want to volunteer to take over some or all of that day? What active role does the TAG want to take?
DO: And what are good ways to get technical discussion going?
Unlikely to attend: SW, TB, RF
IJ: I'm happy to hear reports of progress on this.

[There was no formal resolution, but a general sense that those already involved on the program committee should continue as they are doing.]

Review of comments about Arch Doc

See summary of comments.
[DanC will scribe for a bit]
RF: REST shouldn't be in a section about protocols
TB: how about moving "see more in [REST]" into the intro?
PROPOSED: s/HTTP has been specially.../HTTP 1.1 has been specially.../
IJ: would moving this to the front synergize with your goals to have more motivation up front?
RF: hmm... no...
TB PROPOSED: The most important theoretical work in this area is REST....read more here....
(for intro)
RF: REST is a named set of constraints. The webarch is another named set of constraints (that the TAG finds useful).
DO: I'd be surprised if REST just sort a disappeared...
The document need *not* be modified to change "HTTP" to "HTTP1.1".
TB: If our constraints are not a superset of REST's I'll be worried.
PROPOSED: reduce summary of REST to something in the intro ala "the principles in this doc are based on experience, plus there has been theory/modeling work, the best write-up of which see [REST]".
[discussion of REST, peer to peer, whether REST excludes some P2P stuff...]
RF: if you want to have a section that talks about the properties of HTTP in particular...
TBL: yes, let's do that...
[... more on whether our arch doc should include all the REST constraints, or whether REST is more constraining than what we want...]
RF: what I don't want is for the doc to say "REST applies (only) to protocols"
[PC asks about principles/constraints, which see notes from this morning?]
Resolved: reduce summary of REST to something in the intro ala "the principles in this doc are based on experience, plus there has been theory/modeling work, the best write-up of which see [REST]".
PROPOSED: there should be a distinct section on REST/HTTP style stuff, part of section 4.
Action RF: Draft a section on HTTP/REST, showing rationale, principles, constraints.
1 Introduction
Resolved: Change "RDF" to "RDF/XML" in list of formats, per suggestion from Joseph Reagle.
From Elliotte Rusty Harold: Does SMTP belong in the list of protocols?
DC: When I mail something to someone, there's a URI. And SMTP is a protocol I can use to get the thing. SMTP has a role in Web arch, though different from HTTP's role.
TB Proposal: s/SMTP//
CL: is ftp part of the web? what assumptions are being made?
DC: SMTP has a role... mail messages have URIs... SMTP is one way you can GET the mail message; usually it transfers the bits before you ask for them, but ... see "Protocol - Smotocol" -- TBL: ftp is definitely part of the web; you can get ftp thingies just like HTTP thingies.
DO: ftp is stateful, no?
TBL: No, ftp isn't really stateful ... at this level [... more from timbl, too fast].
DC: "mail data" inRFC 821 refers to RFC 822: "mail data: A sequence of ASCII characters of arbitrary length, which conforms to the standard set in the Standard for the Format of ARPA Internet Text Messages (RFC 822 [2]).
TBL: [... on the hand-off from SMTP to RFC822 to MIME specs, via IANA registry...]
CL: But RFC 822 is not the MIME spec.
TBL: But RFC 822 indirectly refers to the MIME spec.
TB: how is this discussion relevant?
TBL: the question is: should the mail community care about what the TAG puts in the web document? yes, since what we say here affects email.
TBL: "Should the mail community worry about what we decide here?" Yes!!
PROPOSED: Add a sentence explaining why it's in the list.
Resolved: Add a sentence explaining why SMTP is in the list of protocols, pointing to what TimBL writing about spec connections. Include FTP in the list as well.
1.3 Limits of this document
From Brian Carpenter email: Cite RFC 1958 "Architectural Principles of the Internet".
DC: Can we change the name of this section?
Resolved: Change title of section 1.3 to "Scope of this document."

Resolved: Cite RFC 1958 "Architectural Principles of the Internet".

PC Editorial: The word "these" in the last paragraph of 1.3 ("Some of THESE principles...") has an unclear antecedent. Please fix.

Email from Anthony Coates
TB: Web's correct operation doesn't rely on this "componentization".
DC: I want to get rid of the Editor's note, but this proposal doesn't do it for me.
[moving on quickly to question of term "absolute URI reference"]
TB: ... we could say that URIs identify resources, and if the identifier has a #, it's still a URI --
TBL: yes, let's...
TB: But what about staying in sync with the IETF specs?
[we seem to have skipped down to comment from Connolly '"absolute URI reference" considered awkward']
CL: how about just using 'identifier'?
SW: Roy, what do you think we could do about this in the IETF?
RF: depends on who shows up. it's more valuable if individual TAG members speak up than just something from the TAG
[... possible risks involved in the IESG review...]
TB: [... web arch doesn't rely on distinction...]
CL: ... compound docs and such ...
TBL: "we call all those things resources".
... doesn't seem necessary to change the arch doc in response to this.
Resolved: The TAG believes what Coates says in his comment is true, but we don't see any changes necessary in the doc to distinguish the classes of things; we regard all those things, compound or otherwise, as resources.
Email from Dan Connolly: "absolute URI reference" considered awkward (and in one case,overly constraining)"
SW: I think it's folly to be inconsistent with IETF specs for these terms.
DC: My preference is to do the change (use "URI") and state that we are not done with this spec until the IETF makes the change.
DC: I wouldn't want to go to last call without this change in the IETF spec.
CL: I wouldn't want a dependency on a group that doesn't exist yet.
DC: But the editor is in the room!
RF (rhetorically): Where is the BNF for "URI".
RF: The RFC does not define "URI"
(note that it's not critical path to do a WG.)
PC: I hear DC saying we have to commit to this as a group, and to support this as individuals in the IETF forum.
DC: I don't think there are any low-cost solutions here.

DC to RF: When do you expect a new RFC?

RF: Six-month processing time between editor's final draft and when number issued. Timing is not entirely under my control.
DC: how about 'till the IESG decision? that's when the risk goes to zero, no?
RF: right, that's when the risk goes to zero, but I don't really know when the IESG will make their decision, though Q1/Q2 2003 isn't unreasonable.
  1. s/absolute URI ref/URI/ in the Arch Doc.
  2. Note the dependency/inconsistency between webarch and RFC2396. Indicate that work is actively underway to harmonize usage.
  3. TAG participants pipe up in relevant IETF forum.
Action RF: Spell out the "relevant IETF fora" to TAG.
2.1 Resources, URIs, and the shared information space
Email from Joseph Reagle
TB: Did we say "should' because some QNames don't have mappings to URIs and it's ok to use them? That's not what we meant by SHOULD.
TB: no, QNames aren't why we said SHOULD.
DC: "../foo" is a perfectly good reference.
PROPOSED: no, SHOULD is not there to allow the QName exceptions, but we don't need to change the document.
TBL: let's get much more clear about references v.. identifiers. References are strings that occur in documents. but every relative URI reference is short for a URI.
TB/TBL: let's put QName (with mapping, ala RDF [see issue 8]) in with relative URI references just before 2.1
Resolved: The finding on get7 already says why it's a SHOULD, not a must. [validator example]
2.2.1 Comparison of identifiers
Email From Dan Connolly:
Connolly's comment was just an aside.
2.2.2 Interactions with resources
Email from Elliotte Rusty Harold

Topic: Are GETs really safe, e.g., in context of micropayments?

TB: My initial take was that I incurred an obligation when I signed up. Other people disagreed.
[Orchard is excused]
TB: Scenario I'm describing is that I pay a flat monthly fee, then a penny per GET.
[... discussion of pay-per-GET service, and whether this motivates a change to the principle 'retrieval is safe'...]
TBL: Two different layers. Some things are architecturally underneath; not part of interaction between vendor about catalogs, for example.
TBL: the fact that following a link might cause your cell-phone data threshold to get crossed might cost you too.
[Discussion of ecommerce scenarios...]
DC: if I were to deploy a micropayment thingy, I'd agree with Baker: I'd give 403 errors, and let the user POST to pay for the page, and then continue.
Resolved: The TAG agrees with email from Mark Baker - under no circumstances should someone incur obligations by doing GET on a URI.
2.2.4. Absolute URI references and context-sensitivity
Email from Joseph Reagle about section 2.2.4.
TB/DC: note we're already re-writing this principle
TBL: If you say paragraph 1 (of 2.2.4), you have to make a flag to say that there is a security problem here. You should avoid misrepresentation; you should ensure that people are aware of the context-sensitivity.
NW: That's what the principle "Be aware context-sensitivity" says.
TB Proposal: We nuke 2.2.4.

TBL Proposal: Add a security section.

TBL: If you have a privacy policy on your site, and the policy is that it changes after 10pm, that's very misleading.
[I'm interested in a pointer to where/when we discussed this text. IJ responds with minutes of 22 July teleconf]
TBL: separate the stuff before/after "Similarly, http://localhost/ ..."
TB: I suggest deprecating the use of file: altogether.
TBL: I'd like to encourage the use of file: URIs in command-line tools; use "current URI base" rather than "current working directory"
DC: Suppose I have a resource that I identify locally dir.ps. If I mail you that pointer, you'll try to get something that's a different resource. There's a public Web, and in your world, you see that plus some other stuff. There's a public Web, and in my world, I see other stuff. There's a lot of shared context, but ragged edges. We might paint this point in a section on ambiguity. So, it's a myth that there's "one Web"; there's a lot of shared stuff but lots of different Webs depending on your view.
TB: Web technologies are clearly useful in entirely unshared, partially shared, or globally shared contexts. Don't kid yourself that using "file:" is useful in the global context.
CL: I assert that there is one Web. There are portions you can't get to. I assert that DC's local file system is on the Web, with highly protective access control.
TBL: How do you distinguish the architecture considering DC's or CL's view?
DC: In my world, naming is unambiguous. In CL's view, naming is ambiguous.
CL: Not ambiguous if they have your machine's IP address.
TBL: In DC's view, there's something broken: what you can do validly is to make a link from anything private into anything public. But not in the other direction. But every now and again that happens, and that can be dangerous...
TBL Proposal: (1) you can use file: (2) you don't have to put your hostname in if nobody but you will use that URI (3) if you write to the larger context, you should try to find out your Internet hostname and include it in the URI.
SW: Does distinguishing identifiers from references help here?
RF: "Context-sensitive URIs should only be used to identify context-sensitive resources". But that's pretty useless. Example of posting information in global space about managing one's local system.
TBL: I note that http://localhost/ could be regarded as shorthand meaning "before you publish me change me to global IP..."
IJ Proposal: What if we move this to a finding and have a note referring to it?
TB summarizing: There is general agreement that the pizza example and the weather example are similar. Should be merged.
[Back to second question on file:]
SW: I think we can move this to the discussion on "harm around ambiguity".
RF: There is no ambiguity.
TB: A file: URI can be used in an ambiguous manner.
[General agreement that there is no ambiguity.]
TBL: I support file://lskflksdjf.com/etc/foo and "../bin/foo"

TBL: But not file://localhost/etc/host or flie://etc/host

TBL: Rather - be careful when you use file://localhost/.
TB: I think that this is best practice, and is sound.
DC: if anything, this "Be aware..." is a best-practice, not a principle, yes? [nod from TB, SW]
TBL: If the specs are a mess, perhaps we should help clear this up.
re: drive letter in file name
From: Larry Masinter (masinter@parc.xerox.com)
Date: Thu, Jan 09 1997
^ evidence from Masinter that the specs for file: are busted. google search: http://www.google.com/search?q=masinter+file+URL
DC: file: URIs behave differently on different platforms.
Resolved: delete section 2.2.4
2.4 URI Schemes
Email from Danny Ayers
[No resolution]
Some sentiment in support, but discussion not conclusive.
RF: Day Software is willing to host a TAG meeting in Basel (Switzerland), whether it be the one in February or any future meeting.
PC: how about doing that in May, combining it with the WWW2003 trip?
Resolved: to thank the hosts: Antarcti.ca, Schemasoft.
moved to adjourn...
CL: note on my section 3 action, I'm otherwise occupied for the next 1.5 weeks
Next meeting: 7 October.
ADJOURN. With thanks to Stuart for chairing.