[TAP] sync vs async

[Doug Tody]

On Thu, 5 Mar 2009, Paul Harrison wrote:

> As for whether the asynchronous mode should be mandatory or not - I say yes 
> because that is the only way to support the more complex use cases for the 
> service that will actually make the VO different from what we can do with the 
> form based services that already exist for every archive today. SkyServer and 
> CASJobs were were way ahead of their time in terms of an ambition that seems 
> to have been lost now.

This is not the case at all - openSkyQuery and CASJobs are still in
use, and we plan to implement new and better versions of these on top
of TAP/ADQL/VOSpace/UWS/SSO etc., as I indicated in an earlier email.
These are two of our "advanced" NVO use cases.  The main difference
between NVO and the other VO projects seems to be that we also
consider basic data access by scientists and science application
writers to be a high priority, and want to provide simplified access
to support such applications.  For many of the common things users
want to do we do not require all the advanced capabilities.  It is
important to support both types of usage.  Furthermore we can expect
to provide robust capabilities now for the simpler use cases, whereas
the advanced ones are likely to require some time yet to mature.

 	- Doug