1. Introduction › 1.1 Modification Philosophy

1.1 Modification Philosophy

The diverse nature of z/OS systems and the applications for
which they are used creates equally diverse measurement
requirements.  CA MICS was designed as a measurement tool
capable of effectively meeting these diverse requirements.
The approaches provided to do this can be divided into three
groups, as follows:

1.  Standard Features.  Many needs specific to a given z/OS
    site are met with no modification to CA MICS.  The
    principal vehicle for this type of flexibility is the set
    of CA MICS parameters specified during installation.
    This type of solution to a special requirement should
    always be considered first and used if such a solution is
    possible.

2.  User Modification Features.  This group of features
    includes the provision of user exits in the standard
    CA MICS code, the CA MICS Database Tailoring Facility,
    and the CA MICS User Component Generator.  These
    facilities provide the tools and methodology for
    controlled modification and extension of CA MICS by the
    user.  Modifications of this type are the primary topic
    of this guide.

3.  User Modifications to CA MICS Source Code.  Most of the
    source code for CA MICS is shipped with the product, and
    this policy makes major changes to the source code
    possible.  However, this is NOT recommended, and seldom
    is necessary.  Modifications of this type should not be
    undertaken without consulting the CA MICS Product
    Support Group first and investigating all possible
    alternatives.

If you have any special measurement requirement, and are
considering making some modification to CA MICS, we strongly
recommend that you adhere to the following general
principles:

    1.  Always use the most direct approach available to meet
        your need.  Use features in group 1 above before
        those in group 2.  This will reduce the time needed
        to make and maintain the modification.

    2.  If a modification of CA MICS source code as described
        in group 3 above is necessary, then modify as few
        lines of CA MICS code as possible.  If a change
        requires a significant amount of coding, use the SAS
        MACRO facility to include the code (through a
        standard user exit or user-defined user exit) in
        CA MICS code.

    3.  Follow the guidelines in this manual for designing
        modifications and evaluate the benefits and impacts
        of the change before making it.

    4.  Test all changes before implementation.  CA MICS
        provides standard facilities for testing via Test
        database units.  Test methods are described in this
        guide.

    5.  Store changes in IEBUPDTE format.  The LOCALMOD
        change library provided for doing this is described
        in following chapters.

    6.  Keep a complete record of all changes to CA MICS.
        Have the records available at the time you call us
        for product support.

    7.  Do not modify the source code for the CA MICS
        generator facilities.  This includes the CA MICS
        Component Generator,the CA MICS JCL Generator, the
        CA MICS parameter generators, and the CA MICS
        algorithm generator.

    8.  Contact the CA MICS Product Support Group to discuss
        modifications as needed.  This is especially
        appropriate during the planning and evaluation of
        modifications.  A brief contact at this point may
        help you avoid major difficulties.

    These topics are discussed in following sections:

    1 - Vendor Product Maintenance and Support
    2 - Tailoring CA MICS to the User's Special Needs