On 12/2/2013 10:52 AM, Michael Sokolov wrote:
> On 12/02/2013 10:24 AM, Thomas Passin wrote:
>> ...I think that a better analogy is a large construction project like an
>> office building or a large bridge. They often run over budget and
>> schedule, and often develop unforeseen problems. Some of them are
>> almost exactly like previous ones, and some have many new elements.
>> During construction, unexpected problems arise, and once completed,
>> usage patterns may turn out to be quite different from those
>> anticipated. Many of the implementation details are routine and
>> implemented by tradesmen who don't know much about the overall
>> architecture.
> I've operated with that idea for many years, but I'm coming to believe
> it's actively destructive because it leads to pure waterfall thinking:
> design, architect, engineer, build. Where is there a place for an
> iterative design, build, test cycle in building construction?
Well, that's a good point, and one I've yet to think through. You know,
I think of some kinds of industrial plants - chemical or steel plants,
say. When a new process is developed, one often builds a pilot plant.
The pilot plant is on an intermediate scale, larger than lab but smaller
than the eventual full scale. The pilot plant is where the key tricks
of the trade are learned, and process problems are solved. It's where
you learn what scales and what doesn't. You don't generally go from a
lab-scale nuclear reactor directly to a 1000 megawatt generating plant
without building a 100 MW intermediate plant first.
OTOH, even though I dislike waterfall approaches, there are at least
high-level user requirements that are (or should be) known from the
start. Doing iterative approaches doesn't mean that nothing is known up
front. It's often the specification details that should be worked out
later. There's the distinction between requirements and specifications
again. And you model or design at different levels of abstraction
depending on where you are in the process.
In the analogy with construction projects, I'm not thinking so much of
the waterfall aspect as of the mix of routine and unexpected.
Construction, also, is generally thought of as cut and dried, but the
daily reality often requires flexibility and creativity.
