[glue-wg] GLUE 2.0 Specification - draft 41 - Working Group Last Call

[Paul Millar]

Hi Balazs,

Thanks for the feedback.

On Thursday 15 May 2008 14:45:46 Balazs Konya wrote:
> > General: OtherInfo attribute vs. Extension entity association. Do you
> > need both? When to use which? You probably though of this already.

This one stumpted me for a bit.  I believe the distinction is valid, but could 
(perhaps) be better explained.

My understanding is the Extension object is to allow Glue to represent 
completely new objects that cannot be expressed as any of the existing 
objects.  The OtherInfo is for addition additional information to objects 
that can be expressed within Glue.

At the risk of opening a can-o-worms, suppose a grid wants to represent actual 
storage hardware at a site (actual disks and tape libraries).  They could do 
this by instantiating Extension objects (modelled after how CIM schema does 
this, for example), one for each disk and one for each tape-library.

To indicate the hardware relationship to StorageResources, they could add 
OtherInfo attributes to the StorageResource that provides the link(s).

HTH,

Paul.