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Re: LC#127: How to verify 5.7 (Provide programmatic exchange of information in a timely manner.)?

From: Charles McCathieNevile <charles@w3.org>
Date: Mon, 24 Jan 2000 20:30:53 -0500 (EST)
To: Jon Gunderson <jongund@ux1.cso.uiuc.edu>
cc: w3c-wai-ua@w3.org
Message-ID: <Pine.LNX.4.20.0001242026120.24678-100000@tux.w3.org>
I discussed this further with some mebers of the IE team today. It is not
clear what timely means, but my interpretation is that the exchange of
information needs to keep pace with changes in the content, to the externt
that a user can configure a user agent to pause transitions of (for example)
focus, selection, or URI being rendered in order to allow their Assistive
technology to render it completely according to their needs. If the User
Agent's APIs provide the information sugfficiently fast the AT or the network
itself will always be the limiting factor in the speed at which the user can
navigate or browse. (If not, the user agent is unlikely to sell a lot of
copies...)

I am not sure how the user agent or assistive technolohgy communicates whren
to pause. But it seems clear that while the intent of this checkpoint seems
appropriate, it needs to be more clearly verifiable.

Charles McCN

On Mon, 24 Jan 2000, Jon Gunderson wrote:

  Charles,
  1. I am not sure what a "stop" means prgrammatically to a user agent, do
  you have an example of a technology that does this?   
  
  2. How does an assistive technology know when it should use this "stop"
  function and how does it know when it should "start" the user agent again?
  
  Jon
  
  
  At 07:41 PM 1/22/00 -0500, Charles McCathieNevile wrote:
  >I think the question is to make sure that there isn't a sequence of actions
  >performed before the Assistive Technology catches up that result in the user
  >missing out on something that happened. SHould this be ahchieved by allowing
  >a stop to be put on actions of the user agent by an Assistive technology? By
  >blocking an input method while something is waiting? I think this makes it
  >easier to verify the requirement (and I think the feature needs an off
  >switch, although I suspect that is a lower priority).
  >
  >Charles McCN
  >
  >On Fri, 21 Jan 2000, mark novak wrote:
  >
  >  hi Jon:
  >  
  >  At 4:47 PM 1/19/00, Jon Gunderson wrote:
  >  >I propose that we discuss this in the techniques document related to this
  >  >checkpoint.  Probably the easiest thing to do is to state programming
  >  >examples on major plateforms that would be acceptable.
  >  >
  >  >Some technique issues:
  >  >1. In process versus out of process access
  >  >2. Microsoft COM technologies
  >  >3. COBRA technologies
  >  >4. Mac???
  >  >5. UNIX???
  >  >
  >  >I think we will need some programming specialists to help fill out this
  >  >list.  Maybe Rich Schwerdtfeger and Mark Novak could help out and maybe
  >  >talking to some of the people in the Amaya team.
  >  
  >  
  >  I noted this was still a "continued" action item from yesterday's UA mtg
  >  (thursday), so I thought I'd try to toss out some ideas on this issue.
  >  
  >  Let me start by saying I fully agree that we must have timely access
  >  to the exchange of information.  What I stumble on, is how to "verify"
  >  the timely wording.
  >  
  >  First, without checking the list archives, I know this issue of "timely
  >  access" has been around for a long time.  As I recall, this was a question
  >  which repeatedly was not satisfied when people were doing evaluaitons of
  >  the early guidelines against current browsers.  Interestingly enough,
  >  when I asked those reviewers what criteria they used for making this
  >  statement, I heard everything from "no response"  to "well, so and so
  >  said it was".  In other words, nothing quantitative.  This doesn't
  >  surprise me.  I would expect that we each have a different concept
  >  of what "timely" access would be.  Some of us may describe this
  >  as "immediate" while others may have a perfectly usable UA/AT
  >  that allowed a few seconds to lapse.  I don't think anyone knows what the
  >  correct "value" might be that constitutes "timely", thus I'm concerned
  of how
  >  we will "verify" this.
  >  
  >  I know the system responds much faster (information exchange), when
  switching
  >  from an out-of process application which used COM to access the
  >  IE DOM as compared to an in-process application which used COM (e.g.,
  >  also referred to as a browser helper object [BHO]).  I also recall Rich
  >  sent to the list some similar results they had quantified while testing
  >  at IBM.   The technology used to access the information which needs to
  >  be exchanged, can be done in any number of methods.  Some of these methods
  >  you have listed above, of which these and others are already in the
  >  Techniques DOC, in Appendix 5.  AT developers will have to choose
  >  which "method" best matches the needs of their technology and users, and
  >  yes, there will be trade-offs in timeliness, robustness, reliability,
  >  etc., for which again, I'd expect the AT and perhaps the UA developers
  >  to understand and work with.  I think what is important in all this is
  >  that there "is" a way to get the information exchanged, and provided
  >  a AT or UA developer use the most current technology available for
  >  the platform(s) they wish to support, then they have probably given
  >  the user "timely" access.  If not, then I suspect the product won't
  >  survive, since the users won't be satisfied and thus will or should go
  >  somewhere else for a solution (I realize this isn't always possible).
  >  
  >  Can we do better than this to"verify" timely access.  Perhaps.  The
  >  one other thought I had was to provide a "reference" design, maybe
  >  as part of the Techniques DOC., or better yet as a tool off the ER page.
  >  What I'm envisioning the "reference" design would be, is a fully
  >  functional prototype that when run on a "very specific" platform
  >  and operating system, would demonstrate the "timely" response to
  >  making whatever information we deem necessary which shows how a
  >  UA/AT ought to respond.  Then at least the UA group could say to developers,
  >  this "reference" design demonstrates what we feel is necessary.
  >  
  >  Before everyone decides this is a good idea, realize this will take a
  >  considerable amount of work, and we would still have to "quantify" timely
  >  access, and what information we'd exchange/show and many other
  >  details, messy details.  ;)
  >  
  >  Anyway, just my quick thoughts.
  >  
  >  Regards
  >  
  >  Mark
  >  
  >  PS:  Note, there already exits in the Techniques DOC., a URL for
  >  a BHO example, under Appendix 5 also.
  >  
  >  
  >
  >--
  >Charles McCathieNevile    mailto:charles@w3.org    phone: +61 (0) 409 134 136
  >W3C Web Accessibility Initiative                      http://www.w3.org/WAI
  >21 Mitchell Street, Footscray, VIC 3011,  Australia 
  
  Jon Gunderson, Ph.D., ATP
  Coordinator of Assistive Communication and Information Technology
  Chair, W3C WAI User Agent Working Group
  Division of Rehabilitation - Education Services
  College of Applied Life Studies
  University of Illinois at Urbana/Champaign
  1207 S. Oak Street, Champaign, IL  61820
  
  Voice: (217) 244-5870
  Fax: (217) 333-0248
  
  E-mail: jongund@uiuc.edu
  
  WWW: http://www.staff.uiuc.edu/~jongund
  WWW: http://www.w3.org/wai/ua
  
  

--
Charles McCathieNevile    mailto:charles@w3.org    phone: +61 (0) 409 134 136
W3C Web Accessibility Initiative                      http://www.w3.org/WAI
21 Mitchell Street, Footscray, VIC 3011,  Australia 
Received on Monday, 24 January 2000 20:30:54 GMT

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