From: Andrew Gabb (agabb@tpgi.com.au)
Date: Wed Apr 09 2003 - 10:41:48 EST
P. Grant Rule wrote:
> But all models are, by definition, 'wrong'. Every one is an abstraction
> that omits much detail for the sake of simplicity and in order to 'tell the
> tale' and pass useful information to those with less experience.
>
> Hence, all models are also probably 'right'... to some limited extent...
> even rigorous waterfall projects contain elements of iteration, just as
> even in the most eXtreme iterative projects, it is possible to trace series
> of sequential steps when looking at the activities to generate products at
> high levels of granularity (ie. small steps, great detail).
>
> Anyway, who cares? Few systems/software developers ever adhere to ANY
> model, do they?
Good words, Grant. We must remember that 'all models are wrong - some are useful'.
The waterfall model was very useful when it was developed (NOT invented, note - it was really fairly obvious and what good developers did anyway) because it illustrated what many developers were doing wrong. Remember that back in the bad old days many developers were just programmers, with mainly maths background, and had no engineering training or experience.
Boehm extended the model in the late 80s to include prototyping cycles and some other stuff, and called it the Spiral model. This model was also 'wrong', of course. It included the waterfall model.
Virtually all systematically projects in the past, at least those using SA&D (as opposed to OOA&D), have followed these models in part, insofar as there is a mapping from the model to their development process.
So anyone who starts their argument by saying these models are wrong is adding absolutely nothing to the argument.
The two most common criticisms of the waterfall model tend to come from two camps (IMNSHO). The first are those who have been a victim (or consider themselves victims) of the waterfall process police, who have tried to enforce the model using a disciplined/rigid/pure approach. Sometimes they're right - the project needed to use the model more flexibly. More often it has been the objector's resistance to, and lack of understanding of the model, which has caused the problem.
The second are those who don't understand the difference between a model and reality, or who are just naturally superior (in their own estimation). Criticising a simplistic model is easy, and these pontificators can dine out for weeks on their wisdom. Also falling into this group are those who confuse waterfall with 'clean room' and other other more specific techniques and methods based on the waterfall.
As Inge said, there are two types of fool. Those who say 'This is old, and therefore good', and those who say 'This is new, and therefore better'.
Andrew
-- Andrew Gabb email: agabb@tpgi.com.au Adelaide, South Australia phone: +61 8 8342-1021, fax: +61 8 8269-3280 ----- ------------------------------------------------------------------------------- To send a message to this mailing list send it to re-online@it.uts.edu.au. To unsubscribe from this mailing list, email majordomo@it.uts.edu.au with the message `unsubscribe re-online' in the BODY of the mail.
This archive was generated by hypermail 2.1.6 : Mon Apr 14 2003 - 09:00:09 EST