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RE: definition of User Agent

From: Robinson, Norman B - Washington, DC <Norman.B.Robinson@usps.gov>
Date: Thu, 3 Nov 2005 11:32:43 -0500
Message-ID: <EAF95052690D174A833DC58B15AB6A8819E8AC@WADCHQSXM24.usa.dce.usps.gov>
To: "Loretta Guarino Reid" <lguarino@adobe.com>, "John M Slatin" <john_slatin@austin.utexas.edu>, "Christophe Strobbe" <christophe.strobbe@esat.kuleuven.be>, <w3c-wai-gl@w3.org>

Loretta,

	If you intend to clarify the role of what is rendered graphically (to your screen) vs. what underlying information is available about that graphic information,  then I would still offer that in both situations information is processed by a user agent.
	
	If you use a screen reader, it relies on a web browser to render content graphically, and provide the underlying information used by the screen reader itself to provide access. The user agent is the web browser in this scenario. Your screen reader relies on another program to access and render the web content.

	If you use a screen reader, and use a text-mode browser, it renders the content graphically to plain text. It typically doesn't provide the underlying information used by the screen reader, as it has simplified it to the content's base textual information. The user agent is the text-mode web browser in this scenario.

	If you use a telephone voice reader, no matter what the underlying data format is in or technology used, the mechanism through which the web content is accessed and converted into audio would be the user agent. I'd say the ability to manipulate the system verbally isn't part of the user agent. You could think of this as the screen reader vs. web browser as equated to the previous examples.

	If you use a email program that can render web content in-line or as part of your message, then that email program component is a user agent. It doesn't matter if the email program also has modes that doesn't use web content. When it can access and render web content, it is a user agent.

	Since I'm stating what a user agent is, let me give examples of what it is not. A text editor opening web content isn't a user agent. It doesn't manipulate, parse, or render the web content. A word processor that imported the text for web content wouldn't be a user agent, although if it could access and render the web content (e.g., HTML) it could be a user agent. A BASH command-line shell isn't a user agent. It can access and manipulate source files that may be considered web content, but it isn't a user agent because it doesn't render the web content.

	So, although the User Agent Accessibility Guidelines (UAAG) 1.0 defines user agents as conforming to the requirements of the UAAG, the definition of user agent from a functional, abstract, and real-world use model suggests that you can still not conform and have a user agent. I believe they tied conformance with user agent in such a way that they ignore user agents that don't conform. This is close to the argument of do you need validated code to support accessibility, with a twist. My interpretation is they choose to only speak to user agents that conform, which might be the best statement to say that if you don't follow the guidelines, you don't belong.

	I'd also state that I see this clear difference as being key to how people will implement the WAI standards. It also is clear enough to be reasonably determined during a legal argument. I don't think the current definitions are clear. I'll repeat and clarify and earlier post; screen readers or assistive technology should not be mentioned as is currently is in the 2nd definition of user agents below. Assistive technology isn't necessarily (it could be) a user agent. I'd change it to "2.Any software that (retrieves and renders) Web content for users. This may include Web browsers, media players, plug-ins, and other programs. User agents are key in providing additional information (via native accessibility interfaces) so assistive technologies can provide additional or alternate information to the user."

	I hope this adds, rather than detracts from your discussion.

	Regards,


	Norman B. Robinson
	

-----Original Message-----
From: w3c-wai-gl-request@w3.org [mailto:w3c-wai-gl-request@w3.org] On Behalf Of Loretta Guarino Reid
Sent: Thursday, November 03, 2005 10:35 AM
To: John M Slatin; Christophe Strobbe; w3c-wai-gl@w3.org
Subject: Re: definition of User Agent



I think we need a clarification somewhere, either in the definition of "user
agent" or the definition of "programmatically determined", that points out
the interaction between these two definitions.

I worry because I see comments from the working group that "of course X can
be programmatically determined, since the user agent is rendering it".
Although the visual rendering portion of the user agent may have the
information, the assistive technology part may not.


On 11/3/05 7:18 AM, "John M Slatin" <john_slatin@austin.utexas.edu> wrote:

> 
> For what it's worth, the Introductory material for the 30 June working draft
> discusses (and tries to clarify) the definition of user agent.  We quote both
> parts of the UAAG definition, then go on to point out that UAAG generally uses
> the first part of the definition while WCAG 2 generally uses the second part.
> Here's the relevant content:
> 
> <blockquote>
> WCAG 2.0 uses the term user agents according to the definition published in
> the Glossary for the W3C's User Agent Accessibility Guidelines (UAAG) 1.0.
> UAAG
> 1.0 defines user agents in two ways.
> List of 2 items
> 1.The software and documentation components that together, conform to the
> requirements of the User Agent Accessibility Guidelines 1.0
> [UAAG10].
> 2.Any software that retrieves and renders Web content for users. This may
> include Web browsers, media players, plug-ins, and other programs - including
> assistive technologies - that help in retrieving and rendering Web content.
> list end
> 
> UAAG 1.0 most often uses the first definition. By contrast, WCAG 2.0 most
> often uses the second definition. It is important to note that assistive
> technologies
> are included in this definition. (Assistive technologies include screen
> readers, screen magnifiers, on screen and alternative keyboards, single
> switches,
> and a wide variety of input and output devices that meet the needs of people
> with disabilities.)
> 
> </blockquote>
> 
> Maybe the explanatory paragraph could be added as a note to the definition as
> it appears in the Gloassary? This way we stay consistent with UAAG while
> highlighting how WCAG differs.
> 
> John
> 
> <blockquote>
> WCAG 2.0 uses the term user agents according to the definition published in
> the Glossary for the W3C's User Agent Accessibility Guidelines (UAAG) 1.0.
> UAAG
> 1.0 defines user agents in two ways.
> List of 2 items
> 1.The software and documentation components that together, conform to the
> requirements of the User Agent Accessibility Guidelines 1.0
> [UAAG10].
> 2.Any software that retrieves and renders Web content for users. This may
> include Web browsers, media players, plug-ins, and other programs - including
> assistive technologies - that help in retrieving and rendering Web content.
> list end
> 
> UAAG 1.0 most often uses the first definition. By contrast, WCAG 2.0 most
> often uses the second definition. It is important to note that assistive
> technologies
> are included in this definition. (Assistive technologies include screen
> readers, screen magnifiers, on screen and alternative keyboards, single
> switches,
> and a wide variety of input and output devices that meet the needs of people
> with disabilities.)
> 
> </blockquote>
> 
> 
> 
> "Good design is accessible design."
> 
> Dr. John M. Slatin, Director
> Accessibility Institute
> University of Texas at Austin
> FAC 248C 
> 1 University Station G9600
> Austin, TX 78712 
> ph 512-495-4288, fax 512-495-4524
> email jslatin@mail.utexas.edu
> Web http://www.utexas.edu/research/accessibility
> 
> 
> 
> -----Original Message-----
> From: w3c-wai-gl-request@w3.org [mailto:w3c-wai-gl-request@w3.org] On Behalf
> Of Christophe Strobbe
> Sent: Thursday, November 03, 2005 7:49 AM
> To: w3c-wai-gl@w3.org
> Subject: Re: definition of User Agent
> 
> 
> 
> Hi,
> 
> At 05:00 30/10/2005, Gregg Vanderheiden wrote:
> <blockquote>
> I just noticed the definition of user agent in our guidelines
> (...)
> 1.      The software and documentation components that together, conform to
> the requirements of the User Agent Accessibility Guidelines 1.0 (UAAG 1.0).
> This is the most common use of the term in this document and is the usage
> in the UAAG checkpoints.
> 
> 2.      Any software that retrieves and renders Web content for users. This
> may include Web browsers, media players, plug-ins, and other programs 
> including assistive technologies  that help in retrieving and rendering
> Web content.
> 
> (...)
> Isn't the second definition the one we mean most?  Not the first? In fact
> isn't the second definition the only thing we mean by the term user
> agent?
> </blockquote>
> 
> In my opinion, we can only use the second definition. We can't safely
> assume that user agents conform to UAAG: for some technologies, the user
> agent is not something that is installed on a device controlled by the
> user. For VoiceXML applications, the user agent is the VoiceXML processor
> [1] or the "VoiceXML interpreter context" [2]. This is software that is
> installed on a machine that a user accesses by telephone. It acts upon
> events caused by user action (e.g. spoken or character input, disconnect,
> ...) and retrieves files from a document server (e.g. a Web server) when
> necessary.
> 
> 
> [1] In VoiceXML 2.0:
> http://www.w3.org/TR/2004/REC-voicexml20-20040316/#dmlAConformanceProcessor -
> in VoiceXML 2.1 CR:
> http://www.w3.org/TR/2005/CR-voicexml21-20050613/#sec-conform-processor
> [2] http://www.w3.org/TR/voicexml20/#dml1.2.1
> 
> Regards,
> 
> Christophe Strobbe
Received on Thursday, 3 November 2005 16:33:29 GMT

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