[glue-wg] Comparison with CIM

[Maarten.Litmaath at cern.ch]

Hi Owen,

> The most important point is that we all agree that GLUE is not to drive
> storage requirements through its representation of the system. 
> 
> (note representation not model)

Indeed, and the possibility of expressing ACLs in GLUE is not driving
storage requirements.

> Irrespective of which SRM implementation people prefure the problem does
> not disappear just by arguing over ACL implementations . I hope you
> accept my argument that other systems are significant?
> 
> I would suggest you all consider that wLCG should first agree on a
> format before we try and put it in GLUE, I hope you agree?

No.  GLUE should allow the _notion_ of ACLs to be expressed where they
might reasonably be needed.  And we already have ACLs, namely ACBRs.
They do not impose particular semantics.  Instead they allow for any
schema and schema-dependent notions to be expressed.  The VO and VOMS
schemas are just popular examples of an open-ended enumeration.
A grid can decide which schemas it supports.

> We can all pick our own preferred standard, and our favourite
> implementation, but this in no way effects anything as the outcome (can
> we write or read) will always resolve to TRUE or FALSE for a given
> operation, do you agree?
> 
> Since the outcome resolves to TRUE or FALSE and experiments store where
> they write data, the experiment is better placed to store the resolved
> value since this is both already stored and already expressed in a
> standardised way, for example in FOC?

That is a slippery slope.  You could do away with most if not all of the
information expressible in GLUE: it could all be remembered in VO-specific
services...

That happens to be what some of the LHC experiments are doing, but that
was because of (past) instabilities in the standard information system.
We would not want to give VOs even more reasons for bypassing it...

> I am sorry but GLUE cannot be everything, I see it as an advertising
> service, upon which other things can represent information. I hope
> others also recognise the point of the FOC initiative, and if they do,
> and still favor ACL's they should explain why they dont see it as part
> of FOC?

Advertizing what?  "You might store a file here, just try it and remember
the outcome for the next time?"