[DRMAA-WG] Java DRMAA implementation for Condor

[Rayson Ho]

Victor,

(I missed the first part of today's meeting, and only heard the later
part of your intro to the condor-jdrmaa project. May be you mentioned
something that I am missing here)

The condor-jdrmaa SF page says "future versions will reduce the amount
of JNI used, so that eventually, a pure Java..."

IMO, it is hard to implement a pure Java DRMAA library, as the only
way to talk to the Central Manager in Condor, or pbs_server in
PBS/PBSPro/Torque, or mbatchd in LSF is via a TCP/IP socket
connection, yet each DRM has its own protocol.

It's a bit better on the SGE side, as it has JGDI (Java Grid engine
Database Interface) and JMX, but it requires running a JVM in the
qmaster, and it's not really for DRMAA yet:

http://gridengine.sunsource.net/download/workshop10-12_09_07/SGE-WS2007-FutureSunGridEngineCoreEnhancements_SMI_AndySchwierskott.pdf

And my question is, what's the benefit of getting a pure Java
implementation, and what are the problems that cannot be fixed in the
current implementation of using Java wrappers+JNI+C DRMAA?

Writing new Java code to talk to the master machine from scratch is a
big effort, and doing that for each DRM may introduce compatibility
issues -- SGE developers mentioned before that GDI compatibility is
not guaranteed across versions.

FYI, in 2006 the XGrid DRMAA Summer of Code project uses the Java
wrappers+JNI+C DRMAA, and there were a number of things that Ed did to
get it to work:
http://code.edbaskerville.com/2006/07/11/java-bindings-working/

And you can see the background info here:
http://www.ogf.org/pipermail/drmaa-wg/2006-June/000470.html

Rayson



On 9/2/08, Felix, Victor <vfelix at som.umaryland.edu> wrote:
> Hello,
>
> Just wanted to point out that a new project has been set up on
> SourceForge to provide a Java DRMAA implementation for Condor, which has
> been missing. It is called Condor-JDRMAA. The current release is simply
> a wrapper around the C implementation, however future releases will work
> toward a pure Java implementation...
>
> http://sourceforge.net/projects/condor-jdrmaa/
>
> Best regards,
>
> -Victor
>
> --
>  drmaa-wg mailing list
>  drmaa-wg at ogf.org
>  http://www.ogf.org/mailman/listinfo/drmaa-wg
>