Craig:
Thanks for the info! Bill Gates brings up an important point that is infrequently discussed in BA circles: Functional model (which is the same as a business process model) maintainability.
From what I have seen Data Flow Diagrams are truely unique in that they strongly support maintainability. Some examples:
* DFD's have a built-in mechanism that is a lithmus test of completedness (i.e., integration): The data flows themselves. If the model is going to be maintainable - it has to be highly integrated. It is just too much work trying to maintain disjointed models.
* DFD's employ a parent diagram/child diagram scheme where the max number of documented functions per level (diagram) is typcially about seven. Large "big hunker" diagrams are not at all maintainable - trying, for example, to move 30 functions up, or down on the model to squeeze in some additional functions is just too hard.
* Utilize a logical data dictionary so that, a year or so later, we can go back to the model and easily figure it out the specific meanings of inputs and outputs.
I am curious how other modeling techniques simultaneously support the above mentioned maintainability issues?
Tony