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Re: [Xgrid] Re: DRMAA for Xgrid? (fwd)

On Feb 28, 2006, at 12:30 PM, Ernest Prabhakar wrote:

Hi Daniel,

You mentioned that the proceedural bindings would not be a good fit.
What about the OO bindings? We've produced DRMAA specs for the Java
platform and for .Net. From those we've derived a general OO spec,
which is currently known as the IDL spec. Have a look at the Java spec
and/or SGE Java implementation docs. If that's interesting to you, I
can work with you to hammer out an Objective-C variant.

To be honest, I haven't seen much interest in DRMAA for ObjC. The motivation there would actually be more the reverse: taking other Grid Engines and making them Cocoa-friendly. But, that's a different discussion.

More importantly, in discussions on the list -- which you weren't CC-ed on, but are available here:

http://lists.apple.com/archives/Xgrid-users/2006/Feb/msg00037.html

there was *strong* interest in having a procedural C API for Xgrid, which could work with DRMAA. This might make it fairly trivial to generate SWIG bindings for various languages, minimizing the effort of people like Barry and Brian.

The question I have is, "Would the DRMAA bindings provide a sufficiently rich API to *be* the default C bindings for Xgrid?" That is:
a) are they semantically able to cover [most] everything that Xgrid provides?
b) are they semantically compatible with the existing ObjC API?

If so, then it does seem like there's enough interest to start a "drmaa_xgrid" project, to create a DRMAA-compliant C library that 'wraps' the Objective-C API, more-or-less the way pyxg already does for Python.

Does that sound like the optimal way to proceed?

While there's probably some execution overhead, it should be minimal compared to the network traffic. It has the advantages that:
i) you're not dependent on Apple
ii) the code can be open source
iii) it doesn't depend on Xgrid internals, just public API, so it should be easy to maintain
iv) we can build it now, rather than waiting for Leopard


I guess I wonder about point (iii). In some ways not depending on the Xgrid internals (like BEEP) makes it easier to maintain. On the other hand, I wonder if a synchronous/procedural API would be easier to build on top of the BEEP stuff (rather than the XgridFoundation). I think I recall someone saying that the xgrid command line doesn't use XgridFoundation for this reason. Is this true Ernie?

If a procedural APi is built on top of XgridFoundation, the implementation of that APi will still need to do the "fragile" task of managing an NSRunLoop by hand. So it seems like this approach wouldn't result in anything more robust that what we already have (in xgf for example).

But obviously, a procedural API that is built on top of the BEEP layer would probably need to come from within Apple (unless someone wants to reverse engineer the BEEP layer). That would mean the benefits of points i), ii) and iv) are lost.

Personally, i would rather wait for Leopard and have The Right Solution rather than another semi-robust open source solution now.

This leads to a question for Ernie: Do you think that it would be easier/more robust/better to have a procedural (C) Xgrid API based on the BEEP layer rather than XgridFoundation?

Glad to see this stuff being discussed.

Cheers,

Brian

If there's a general consensus that this is A Good Thing, all we need is some people to agree to act as a Core team, and place to host it. I can get us a DarwinPorts project, if that would help; though if someone else wanted to "own" it, or get it on sourceforge, I'd be fine with that as well.

Certainly if it matures and becomes heavily used, we can look at bringing it into Xgrid proper at some future point. But I'd prefer to first validate it out in the open.

Best,
-- Ernie P.


On Feb 28, 2006, at 9:10 AM, Daniel Templeton wrote:

Ernie,

You mentioned that the proceedural bindings would not be a good fit.
What about the OO bindings? We've produced DRMAA specs for the Java
platform and for .Net. From those we've derived a general OO spec,
which is currently known as the IDL spec. Have a look at the Java spec
and/or SGE Java implementation docs. If that's interesting to you, I
can work with you to hammer out an Objective-C variant.

Also, you mentioned Python. There is already a Python binding, built on
the C binding (using SWIT) but modeled after the Java language binding,
so it's an OO binding.

Daniel

Andreas Haas wrote On 02/28/06 10:50,:

FYI:

I'll bounce that mail to you to allow you jump in.

Andreas

---------- Forwarded message ----------
Date: Mon, 27 Feb 2006 11:52:23 -0800
From: Ernest Prabhakar <email@hidden>
To: xgrid users <email@hidden>
Cc: Andreas Haas <email@hidden>
Subject: DRMAA for Xgrid?

Hi all,

Is anyone here familiar with the Distributed Resource Management
Application API (DRMAA):

http://www.drmaa.org/

While their procedural bindings not a great match for our Objective-C
API, it occurred to me it might be of interest to some of you work on
Python et al. Have any of you run into DRMAA-enabled applications in
your environment?

If this is something you're interested in exploring, please reply to
the list, and CC Andreas Haas (above) from the DRMAA working group.

Best,
-- Ernie P.
-------------------------------------------------------------------- ----
-----------------
Ernest N. Prabhakar, Ph.D. (408) 974-3075 <ernest at apple.com>
Xgrid Product Manager, Mac OS X Product Marketing
Apple Computer; 303-4SW 3 Infinite Loop; Cupertino, CA 95014




--
******************************************************
*         Daniel Templeton   UMPK18 x83749           *
*        Staff Engineer, Sun N1 Grid Engine          *
******************************************************
* "What's the sense in never thinkin' 'bout the tomb *
*  When you're much too busy returning to the womb?" *
*                  -They Might Be Giants             *
******************************************************



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 >[Xgrid] Re: DRMAA for Xgrid? (fwd) (From: Ernest Prabhakar <email@hidden>)



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