RE: Status: D-AG0007 - reliable, stable, predictable evolution

hi, Damodaran,

I would regard the stability of a web service as the stability of the
identifier (the URI) and the logic concepts associated with it. For example,
if a company sells car at http://xys.com/buy/car, one expects the URI to be
stable so one can bookmark this URI and one expect to buy a car not a book. 

The second part is more tricky.  How about: "the architecture should enable
a web service to reveal its attributes to its consumers and verified
independently by its consumers or third parties so a selection mechanism can
be enforced. "?

Note the attributes can be more than just those needed in order to discover
the web service.

Hao

-----Original Message-----
From: Damodaran, Suresh [mailto:Suresh_Damodaran@stercomm.com]
Sent: Friday, March 15, 2002 3:08 AM
To: 'Hao He'; www-ws-arch@w3.org
Subject: RE: Status: D-AG0007 - reliable, stable, predictable evolution


Hao,

-----Original Message-----
From: Hao He [mailto:Hao.He@thomson.com.au]
Sent: Wednesday, March 13, 2002 6:32 PM
To: Damodaran, Suresh; www-ws-arch@w3.org
Subject: RE: Status: D-AG0007 - reliable, stable, predictable evolution


I belive that the "Reliability, stability, and predictable evolution of web
services" are more important and useful than those of the reference
architecture, so we should add it as a goal.
<sd>
I generally agree. I am unsure of what "stable webservice" means, though.
What is it to you, and how is it different from "reliable web service?"
</sd>
 
It might also be desirable if a web service can be easily evaluated from
consumers' point of view. This would allow 'natual selections' on competing
service providers and service implementations.
Should this be a non-goal or part of the new goal?

<sd>
It would make sense to add this as a goal if web services world is seen
as an ecology, where Darwinian selections may occur. (I have visions of
striped web services lengthening their neck and becoming tall web
services:-)

Seriously, how would you word the goal statement?
"architecture has the goal of enabling selection of web services"
Note that the implications are profound - just as an example,
discovery of web services will immediately come under the scope of WS-A.

Cheers,
-Suresh
</sd>
 
Regards, 
Hao

-----Original Message-----
From: Damodaran, Suresh [mailto:Suresh_Damodaran@stercomm.com]
Sent: Thursday, March 14, 2002 10:48 AM
To: www-ws-arch@w3.org
Subject: Status: D-AG0007 - reliable, stable, predictable evolution


Goal:
    Goal statement "To develop a standard reference architecture for web
services that is reliable, and stable, and whose evolution is predictable
over time"  This goal has not been revised, and thus, stands.
    "Reliability, stability, and predictable evolution of web services" is
noted in [1] as a non-goal, and perhaps
    should be added to our goals.
 
A proposal was submitted to the WG [1], and was evaluated. The proposal
included measures that
can be taken by WS-A to address reliability, stability, and predictable
evolution through the formation
of C-sets, or "consistent sets" of standards within WS framework.
    A question was raised whether C-sets could stall predictable evolution
[3].
    Similar question was posed in [2] in terms of extension.
    Ensuring "backward compatibility" of individual standards could
potentially address this issue [4]. This will also address the "principle of
partial understanding" in [5].
 
For other questions and responses, please refer to the mails directly.
 
Further, I was referred to [5] as a possible important source. If anybody
has any other source, 
please send them to me. A new rev of the proposal will be made later in
light of the comments and [5].
Date TBD.
 
Regards,
-Suresh
 
 
[1] http://lists.w3.org/Archives/Public/www-ws-arch/2002Mar/0148.html
<http://lists.w3.org/Archives/Public/www-ws-arch/2002Mar/0148.html> 
[2] http://lists.w3.org/Archives/Public/www-ws-arch/2002Mar/0158.html
<http://lists.w3.org/Archives/Public/www-ws-arch/2002Mar/0158.html> 
[3] http://lists.w3.org/Archives/Public/www-ws-arch/2002Mar/0180.html
<http://lists.w3.org/Archives/Public/www-ws-arch/2002Mar/0180.html> 
[4] http://lists.w3.org/Archives/Public/www-ws-arch/2002Mar/0234.html
<http://lists.w3.org/Archives/Public/www-ws-arch/2002Mar/0234.html> 
[5]  <http://www.w3.org/DesignIssues/Evolution.html>
http://www.w3.org/DesignIssues/Evolution.html