[drmaa-wg] Definition of "system"/discovery in getDrmSystem?

[Peter Troeger]

> There's no clear definition for what a "DRM system" is in the 1.0 
> specification. I understand that it could be implementation- dependent,
> but my assumption is that the generally accepted meaning  is "something
> you can submit jobs to." On SGE, for example, then, it  seems then that
> a system is the same as a cell. On Xgrid, they're  called, simply
> enough, grids.

Basically, this is something we already discussed and solved for the
upcoming final 1.0 spec:

http://forge.gridforum.org/sf/go/artf2822?nav=1

> The SGE implementation seems to eliminate this concept altogether,  and
> just require that SGE_ROOT and SGE_CELL be set, so when I call 
> getDrmaaImplementation and getDrmSystem (via Java) on SGE before 
> initialization, I get:
> 
> getDrmaaImplementation: DRMAA 1.0 Java language binding 0.5 -- GE 6.0u7
> getDrmSystem: GE 6.0u7
> 
> SGE seems to displace the need for multiple "DRM systems" within  DRMAA
> by shifting the selection to the SGE_CELL environment variable.  Is that
> an accurate understanding?

Citing myself from the tracker:

-- snip

"contact string" is a resource identifier that allows to contact a DRM
system instance (e.g. Condor central manager machine at
123.123.123.123:4444)
"DRM system" denotes a type of DRM software (e.g. Condor, SGE)
"implementation" denotes a specific version of a DRM system (e.g. Condor
v6.6)

-- snip

So for SGE your impression seems to be right - but I am not the SGE guy ;-)

> I could certainly do something similar with Xgrid--let the user  select
> a default grid elsewhere--but, since Xgrid natively supports 
> Zeroconf/"Bonjour" discovery of grids, it would be nice to expose  this
> discovery in DRMAA.

>From a DRMAA perspective, it would be better to state all possible DRM
instances (== XGrid grids == SGE Cells ???) as the result list of
drmaa_get_contact() before drmaa_init().

> So, the question is: does it make sense to expose Zeroconf grid 
> discovery via getDrmSystem?

If you take the proposed definition above, getDrmSystem() is not the
right one. You would use this with a DRMAA library supporting multiple
DRM systems, like Condor and XGrid, in one implementation.

Regards,
Peter.