[SAGA-RG] Fwd (andre at merzky.net): Re: JSDL - SAGA

[Thilo Kielmann]

All,

On Tue, Feb 20, 2007 at 09:13:20AM +0900, Pascal Kleijer wrote:
>
> I first sought about a solution like Hartmut, but SAGA is targeting Grid 
> newbies, so JSDL might be out of the 80/20 rule scope.


may I slightly disagree?

SAGA is targetting those application developers who want (or have) to
focus on their own application domain. As Andre said, they are scientists,
but not computer scientists. Newbies are part of this population, but more
experienced people, too. For those people we must at least be open enough
to let them use "real stuff" in the framework of SAGA.

This is really important. I currently watch what is happening to the (Java)
GAT: users liked it, and over time, they still like, but need "more".
The current GAT approach is to keep adding features. With SAGA, however,
we cannot do this once a standard has been nailed down. so we have to make
SAGA open in a way that combines its main asset, the simplicity, with the
ability to also support people who need to get more power at their hands.

As I wrote last friday, these are conflicting goals.

I am still convinced we should use SAGA's job descriptions and allow them
to be subclassed, e.g. to be come JSDL job descriptions.
(Non-OO languages will have to use type casting to deal with, but this is
certainly not the only place where our OO design will look a bit non-natural
in non-OO languages.)

Also, Andre has a point w.r.t. OGSA. At OGF19 we had a discussion with 
Andrew Grimshaw after his talk about naming. This is another issue where
SAGA needs to be "open": we must keep our simple approach to naming entities,
but we must be able to support OGSA WS-Naming for those people who care.
If we fail to provide this openness, then we fail substantially in
providing an API for OGF-designed middleware.

The idea we had at OGF19 was to have the SAGA spec on one hand, and a
"profile" on the other, in which we describe how SAGA can/should be used in
combination with OGSA-related middleware.

Getting back to the JSDL issue:
- the SAGA interface itself should stay clean from JSDL-specifics, unless
  they are so good that we like them to be used within "core SAGA"
- we have to define a "hook" for JSDL-like job descriptions to be used along
  with SAGA (and not just in the backend implementation)


Thilo
-- 
Thilo Kielmann                                 http://www.cs.vu.nl/~kielmann/