WIMS> CIM> FW: Question to CIM Core about evolution vs replacement of classes.

From: Richard_Landau@Dell.com
Date: Thu Jun 15 2006 - 14:17:33 EDT

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    This has not climbed onto the CIM Core agenda yet. Much urgent business
    in front of it. (The original message went to entire Core group.
    Second msg only to chair. I will reword more strongly and resend to
    group.)
     
    rick

    ________________________________

    From: Landau, Richard
    Sent: Tuesday, June 06, 2006 17:40
    To: 'crandall@brocade.com'
    Subject: FW: [wg-cimcore] Question about evolution vs replacement of
    classes.

    John, can we put this question that I posed on the Core agenda, please,
    for a short discussion in the near future. Here's a short version just
    to get the idea across.

     

    If I add this many properties to a class, is it still the same class?

              1 Y N

              2 Y N

              5 Y N

            10 Y N

            20 Y N

            50 Y N

          100 Y N

     

    Is there an obvious breaking point? Is there a breaking point at all?
    Or is it reasonable to add lots of properties that were mistakenly left
    out in the first draft?

     

    Thanks.

     

    rick

     

    ________________________________

    From: Richard_Landau@Dell.com [mailto:Richard_Landau@Dell.com]
    Sent: Friday, June 02, 2006 10:27
    To: wg-cimcore@dmtf.org
    Subject: [wg-cimcore] Question about evolution vs replacement of
    classes.

    (For discussion in mail threads or on the concall)

    Procedural question for CIM Core: How much can one change a class before
    it isn't the same class anymore?

    In the PWG (Printer Working Group) work on updating the CIM printing
    classes, we have concluded that a couple of the classes will require
    major facelifts. CIM_Printer, for example, currently expresses about
    thirty properties. A few of these will be deprecated and moved to
    CIM_PrintService, but the real question concerns properties that it does
    not currently express at all.

    The industry model of a printer device includes a *lot* of properties
    that are not currently in CIM_Printer. We will certainly attempt to
    reduce the number by collecting many of the properties into Capabilites
    and Settings classes, and perhaps by splitting some features into other
    separate classes (but not to the point of hyper-normalization). Even
    so, the size of the class is likely to double.

    So the question is, Is it plausible to add twenty, or thirty, or more
    properties to a class and still call it the same class?

    - Shall we proceed on the assumption that we are simply going to improve
    CIM_Printer (and the others)?
    - Do classes ever revert from final status to experimental status
    because of such changes?
    - Will Core insist that we define an entirely new class, e.g.,
    CIM_PrintDevice, with all the new properties and then deprecate the old
    class in favor of the new one?

    I'm not asking for a decision of any sort at this point, but for a sense
    of the working group's process in such cases.

    Thanks.

    rick

    ----------------------
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    +1-512-728-9023, One Dell Way, RR5-3 MS 8509, Round Rock, TX 78682



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