Subject: RE: FW: Probable Cause

From: "Andrea Westerinen" <[email-masked]>
Date: Thu, 2 May 2002 00:10:16 -0700

Randy and Dan,
I would like to clarify a few items about the DMTF mapping of ProbableCause.
There is concern that we have 1:n, n:1, and n:n mappings between the DMTF
and the ITU stuff to consider.  I would like to explain some of the issues
and how the DMTF approached them.  Probable Cause in CIM really has 2
fields - one enumerated "cause" and another string field
(ProbableCauseDescription) with more details.  It is assumed that the
Description property provides any additional details that may be available.

In an early posting, Randy noted that CIM's Cause="HVAC Problem" was an
example of a 1:N mapping (CIM to ITU).  Specifically, CIM's HVAC Problem
mapped to ITU's coolingSystemFailure or ventilationSystemFailure or
airCompressorFailure or airConditioningFailure or airDryerFailure or
heatingVentCoolingSystemProblem.  However, we made that choice consciously
since it was not possible to define the difference between
coolingSystemFailure, airConditioningFailure and
heatingVentCoolingSystemFailure.  So, if we could not define when one would
be used versus the other - we opted for a general enumerated value and a
specific description field to indicate what else might be known.

Andrea

-----Original Message-----
From: Randy Presuhn [mailto:[email-masked]]
Sent: Wednesday, April 17, 2002 1:56 PM
To: [email-masked]; [email-masked]
Cc: [email-masked]
Subject: RE: FW: Probable Cause

Hi -

> content-class: urn:content-classes:message
> Subject: RE: FW: Probable Cause
> Date: Tue, 16 Apr 2002 14:05:49 +0300
> Message-ID:
<[email-masked]>
> From: "Romascanu, Dan (Dan)" <[email-masked]>
> To: "Randy Presuhn" <[email-masked]>, <[email-masked]>,
>         <[email-masked]>
> Cc: <[email-masked]>
...
> I am not sure that I follow you completely. Our concept is that the ITU
list is the basic staff and reference model for the list of possible causes.
We should add staff from other sources only when we think something is
missing in the ITU list. This was the reason - as I understood it - to look
into the DMTF stuff.

If we're just passing through stuff from other sources, we don't
even need to maintain the list.  But if we really do care what the
enumeration *means*, we've got a problem.

What worries me here is the question of what kind of guidance we can
provide to those using these values.  If our list includes everything
from both the DMTF and ITU sources, there are several possible values
that might be used to report, for example, a heating problem.

>
> If somebody invents a better and greater list later, he could go to IANA
and have the his new values added to the TC, as well as explanatory
commented text to document the mapping of other values from his list in the
previously available values.

That's fine.  My question is how someone implementing the
code to generate an alarm would choose a particular value for
ProbableCause from the overlapping possibilities.  I think
it amounts to recommending to implementors that they choose
the narrowest semantic which does not exclude the real
"probable cause".

> IMO the text assigning the responsibility of administrating the list to
the disman wg for eternity should be changed.
...

Agreed.

 ------------------------------------------------------
 Randy Presuhn          BMC Software, Inc.  1-3141
 [email-masked]  2141 North First Street
 Tel: +1 408 546-1006   San Josi, California 95131  USA
 ------------------------------------------------------
 My opinions and BMC's are independent variables.
 ------------------------------------------------------