Kimbo:
In your response to your first question:
A function\process is defined by its inputs and outputs. (These inputs and outputs are typically, esp in info systems, data flows.). Do you see such? To me, this is a real fundamental, and extremely important concept. If you or anyone can refute such, then I am in need of "getting my head straight". In such case, please, PA LEEZE, let me know!
If you agree that a function\process is defined by its inputs and outputs, and, as the prospect of systematic input\output analysis seems to the last thing that the vast majority of BAs want to do, without a technique that places PRIMARY emphasis on inputs and outputs, rigorous input\output analysis just ain't going to get done. And therefore, especially in larger scale eforts, function\process analysis is going to be very incomplete.
In response to your second question:
If you believe that processes are defined by there inputs and outputs, than what is the process driven approach that you refer to? To my knowledge, only data flow diagrams focus primarily on process inputs and outputs and therefore, only they are process-centric. BPMN, for example, has some provision for capturing inputs and outputs, BUT the inputs and outputs are placed on the same diagram as is a bunch of other - secondary - stuff like: flow of control, sequencing, timing considerations, and swim lanes. Result: Input/output analysis suffers, as, to qoute Yourdon (DeMarco?) "If we want to get anything done [correctly], we must not try to get everything done - at lease not initially."
Kimbo, my very first post to this site was entitled "The Lost Secret of Business Analysis". In it I talked about the difference between a logical, natural partioning (i.e, partitioning as a result of flowing the flows of data) and forced, artificaial partitioning. As per DeMarco, in data flow diagraming, the BA follows the natural flows of data. When data flows naturally converge, or diverge the BA has discovered a logical process. The method itself actually prods the analyst through process discovery. Especially for larger scale efforts, such a partioning, is going to result in a radically different partitioning than any other way.
Tony
Nobody is good at partitioning just based on intiution. What matters is being good at using a methodology that will prod you through the partitioning process and make "holes" in your thinking glaringly obvious. Hate to say it, but partitioning based on timining is another example of forced, artificial partitioning: