Re: PG: Hackers and Painters

[Noel Welsh <address@hidden>]

--- Dan Sugalski <dan@sidhe.org> wrote:
> I'm picturing an architect taking the project
> manager, construction 
> engineer, and the major subcontractors for a new
> skyscraper, sitting 
> them down, and starting with "let me tell you a
> story about a 
> building..."
 
> XP's "Go for it, good luck, don't forget to write"
> methodologies have 
> some scaling issues.

I don't think your characterisation of XP is accurate,
but see "XP on a Large Project: A Developer's View" at
http://www.thoughtworks.com/library/index.html for a
discussion of scaling issues in XP and how the
methodology was modified to cope with them.

Getting back to the "let me tell you a story" bit
there are two things to note here:

1.  XP terminology is full of squishy phrases like
"telling stories".  E.g. the XP practice called "The
Planning Game" (and of course the name Extreme
Programming itself!) You should not be confused into
thinking that XP is undisciplined because the language
used to describe it is not written in a formal style. 
To the best of my knowledge no XP enthusiast
recommends developing the system metaphor with a
guitar around the campfire, and coyotes howling in the
distance.

2.  The System Methaphor is about the fundamental
design of the system.  For example, in a compiler it
might be "this program is a pipeline of
transformations from one intermediate language to
another" (e.g. GHC).     For Emacs it seems to be
"This is a Lisp VM with a bunch of text editing
libraries".  For a web site it might be "this program
is a collection of view into data stored on the
database" (not a very good example).  From what I know
of architectural practice it is remarkably similar. 
Building have their driving aesthetic - for the Sydney
Opera House it was the initial sketches based on sea
shells.  For the the Gherkin (a building going up in
London at the moment) it was the constraint that every
office has a window.  Get a bunch of architects
together and they talk architectural theory all night
- these are the System Metaphors behind their designs.

Noel

=====
Email: noelwelsh <at> yahoo <dot> com
Jabber: noelw <at> jabber <dot> org

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