Notes from CIM Core meeting on PWG update of Printer model
RBL 20061117
The meeting went very well, I think. There were six reasonably vocal
members of Core present, and Ira called in to monitor and lend support.
Overall, close but no cigar on the modeling. The parts I thought would
be controversial were not, and vice versa. For instance, no one had a
problem with adding a hundred new properties or a dozen new classes.
The major comment on the model was that the table header classes ought
to be removed if possible. That is, if the table headers are present
only for the purpose of providing structure, then they should probably
be eliminated. If the headers contain scalar properties, maybe those
properties can be promoted to the base class, and then the empty headers
will be superfluous. The resulting model would be simpler and not
contain any unnecessary structural plumbing.
Ira and I spoke after the meeting and agreed that this is probably a
good simplification. It makes the conceptual model simpler and flatter
(fewer layers of hierarchy), even though the resulting hub-and-spoke
instances will be wider. I will draft new pictures long before our next
concall. (Aesthetically I don't like the result; looks like an erector
set with pieces missing, lacks symmetry. But one must adapt to the
local culture.)
Another class of comment concerned the so-called multi-tenant CIMOM
problem, which I have been working on with groups here and in DMTF for
six months. The problem is somewhat obscure down in the technical
details, and is really a CIM implementation question, not a modeling
question. The gentleman did bring up a third class of "multi-tenant"
issues that we have not considered before, that multiple providers might
publish different views of the same printer device in the same
repository. But -- and this is the key question that I forgot to ask --
how is that different from the current situation? That can and does
happen today for other types of devices. The richer Printer model will
simply tempt people to do it more often in the future.
Overall, six or seven out of ten. The hard parts passed. We just have
to prune the structure a little.
rick
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Richard_Landau(at)dell(dot)com, Stds & System Mgt Arch, CTO Office
+1-512-728-9023, One Dell Way, RR5-3, MS RR5-09, Round Rock, TX 78682
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