Datasheet

Telling Stories
13
wasn’t much of a talker. The credit risk system was a series of jobs that ran at
night, moving huge quantities of data around and then producing a lot data
that credit analysts could query the next day. When the development manager
would try to explain it to me (there was no real documentation), he would talk
in great detail about what all the parts did and show me schema diagrams and
other stuff I couldn’t make sense of.
Fortunately, I was at the same time taking a class in analyzing information
systems at night. I didn’t know it, but I was learning Structured Analysis.
The teacher never said anything about stories, but one night he said, “Every
system is basically the same. It takes data from somewhere, it does something
to it, and then it puts it somewhere else.” We also learned a simple form of
diagram. (See the example of a Yourdon DeMarco data flow diagram earlier
in this chapter.) These diagrams showed data moving between what he called
“processes.” Each process was an action that changed data (not a thing). The
lights went on.
The next day I asked my development manager to explain his system in a
different way. “Let’s say your system is a lumber mill. The data your system
works with is like the wood the lumber mill processes. I want you to tell me
the story of how your lumber mill makes wood products, starting with the
trees in the forest and ending up with finish‑grade plywood.”
From then on, it was easy. We started with where all the data came from
and I made him explain everything that happened to it until all the differ‑
ent kinds of finished data were saved at the end. Along the way he explained
what was required at each step. I didn’t write very many notes in prose as I
had been doing previously, but drew diagrams with descriptive names for
processes and data.
Thinking of what I was doing as writing a story made everything fall into
place. Even if what I was producing looked pretty “techy,” it moved along and
made sense the same way a story does.
Making Structured Analysis into a Story
I’ve made some grandiose claims about the ability of telling stories to rescue
the requirements‑writing process. I’ve also discussed Structured Analysis and
how it defines the basic tools of analysis that I believe are the best ways to
approach requirements writing. Those of you who know something about
Structured Analysis may puzzle over how I embrace these two approaches. The
results of Structured Analysis are usually not considered a narrative. Many of
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