The Unique Benefits Of Data Flow Diagrams For Task Analysis

Subject: The Unique Benefits Of Data Flow Diagrams For Task Analysis
From: Tony Markos <ajmarkos -at- yahoo -dot- com>
To: "TECHWR-L" <techwr-l -at- lists -dot- techwr-l -dot- com>
Date: Fri, 29 Oct 2004 11:13:52 -0700 (PDT)

--- Bruce Byfield <bbyfield -at- axionet -dot- com> asks:

Specifically, what makes it [Data Flow Diagrams]
different from other task-analysis methods?

Tony Markos responds:

Here it is again:


ONLY DFDs actually prompt you through a task
analysis. How? By following the flows of data as they
naturally combine and split apart, we flush-out
essential tasks that may very well have gone
undiscovered otherwise. And thats what analysis is: a
discovery process.

When we are finished with our analysis using DFDs, the
"chunks" of tasks that we have on our diagrams
represent what the gurus in analysis often call a
"natural partitioning" of the system.

Compare this with ALL other task analysis (note: same
as functional analysis) modeling techniques -
including Use Cases, all other UML functional modeling
techniques, the hierarchal task analysis techniques
espoused by the end-user task analysis community,
logical (If-Then-Go-To) flow charts, task analysis
techniques espoused by the QA community, on and on and
on. With ALL these other techniques, we first draw
boxes, or ovals, or stick men, or whatever to
represent whatever tasks (functions) that happen to
pop into our mind at the moment. And then we try to
connect them together. The problems with these
"connect-the-boxes" approaches:

* Unless the task happens to pop into our mind,
there is an excellent chance that in will remain
undiscovered; we are NOT prompted to "flush-out" the
gaps in our understand. This is a killer for larger
scale projects!

* The resulting "chunks" of tasks represent what
analysis gurus often refer to as a "forced artificial
partitioning" of the system. It would take too long
to explain what this means. Let me just say that
anything that is forced and artifical is just plain
wrong. Again, big problem.

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