Re: UMLish modellers?
Re: UMLish modellers?
- Subject: Re: UMLish modellers?
- From: "Erik M. Buck" <email@hidden>
- Date: Sat, 8 Sep 2001 19:08:56 -0500
In my experience, UML modelers are just an expensive time consumer intended
only to make in experienced non-programmer managers feel like they are
managing something. The final design never matches the diagrams which means
that the diagrams are not even good documentation. The basic and essential
problem with modelers is that they do not help with the hard part of the
problem of software development.
If there is no rational specification for a piece of software, there is no
way to verify that the software meets the specification at the end of the
project. What is the point of designing something that is not specified ?
How is a design evaluated without a specification to compare? Specifying
non-trivial software a-priori is very hard!
When managers admit that there is no way to write a full specification
up-front, then they must admit that there is no way to build a full design
up front either. UML style tools do not support the only methodology that I
have ever seen succeed (outside of aerospace safety critical software which
is a different issue). The only successful large software that I have seen
succeed has been iteratively developed. Start with a kernel of
functionality and keep adding layers, re-evaluate, test, redesign, repeat
until done. The thing about that approach is that managers hate it. They
can not plan it. Sometimes work has to be thrown out. They can not say how
many iterations are needed before completion. They can not say when the
project will be complete. They can not say how much the project will cost.
Iterations are the price of experimental software development. Many times,
we just have to experiment and try different things in order to find a good
solution. A good large application is like a scientific breakthrough. It
is hard to have a breakthrough on a schedule.
If the customer can not specify what they want, we have to experiment to
discover it.
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