[ogsa-wg] OGSA Information Services

[Donal K. Fellows]

guru prasad wrote:
> I have some corrections and questions. I have highlighted those in the 
> attached document. Can someone please help me understand.

Going through your comments (extracted from the document)...

Comment #1:
> What information. Information about the resource or the fact that the
> information provider is on the same host. Too many “This”

Agreed, that paragraph is confusing. (I suspect, but do not know, that
the information you highlighted was the information produced by the
"resource-level provider" but that's just my reading...)

Comment #2:
> Does this mean even the resource level information provider is not
> required??? Or are we saying the service that provides the capability
> to query is not required????
> 
> If the answer to the first question is yes then, I would say it may
> still be required. Instead of site level information registry getting
> overloaded with queries about the resources it has, if one has a
> visibility of a particular resource he could just query that resource.

I'd say that while the resource-level provider is not a priori required,
it has to be there conceptually. Sites are free to use other mechanisms
to actually do the information provision though.

On the other hand, I really disagree with your second paragraph there.
One key gain from having a site-level information system is that this is
a prime location for carrying out queries for resource discovery and
scheduling. If you require everything to ask the end resources directly,
then anything that actually needs to look at many resources will end up
being dog slow because of the amount of network traffic needed to take
any kind of decision (trust me, I've tried this!) A site-level info
system is a major optimization, especially if you do not require all
information within it to be entirely timely.

Comment #3:
> Should it say that the developer of the resources could be the
> information provider ???? This is not clear from the sentence.

That sentence is wildly unclear, but I suspect it's talking about some
kind of API for basic info providers to make it easier to write the
actual information sources. However, I wonder whether this falls more
within the remit of SAGA - do they do server-side APIs? - since OGSA
(and related groups) has tended to focus on the wire view of interop.

Donal.