[ILUG-Social] [OT] the dangers of reusing objects

[Miles]

I just thought I had to forward this on for all those OO programmers out
there...........


> Subject: Killer Kangaroos
> 
> Careless code recycling cause killer kangaroos Take Up Arms Against
> Australian Air Force
> 
> The reuse of some object-oriented code had caused tactical headaches for
> Australia's armed forces.  As virtual reality simulators assume larger
> roles
> in helicopter combat training, programmers have gone to great lengths to
> increase the realism of their scenarios, including detailed landscapes
> and -- in the case of the Northern Territory's Operation Phoenix --
herds
> of
> kangaroos (since disturbed animals might well give away a helicopter's
> position).
> 
>  The head of the Defense Science & Technology Organization's Land
> Operations/Simulation division reportedly instructed developers to model
> the
> local kangaroos' movements and reactions to helicopters.  Being
efficient
> programmers, they just reused some code originally used to model
infantry
> detachment reactions under the same stimuli, changed the mapped icon
from
> a
> soldier to a kangaroo, and increased the figures' speed of movement.
> 
> Eager to demonstrate their flying skills for some visiting American
> pilots,
> the hotshot Aussies "buzzed" the virtual  kangaroos in low flight during
a
> simulation.  The kangaroos scattered, as predicted, and the visiting
> Americans nodded appreciatively... then did a double-take as the
kangaroos
> reappeared from behind a hill and launched a barrage of Stinger missiles
> at
> the helpless helicopter.  (Apparently the programmers had forgotten to
> remove THAT part of the infantry coding.)  The lesson? Objects are
defined
> with certain attributes, and any new object defined in terms of an old
one
> inherits all the attributes.  The embarrassed programmers had learned to
> be
> careful when reusing object-oriented code, and the Yanks left with a
> newfound respect for Australian wildlife.
> 
> Simulator supervisors report that pilots from that point onward have
> strictly avoided kangaroos, just as they were meant to.
> 
> --From June 15, 1999 _Defense Science and Technology Organization
Lecture
> series_, Melbourne, Australia, and staff reports.


	....Miles 

kcolfer at iol.ie
kieran.colfer at ireland.sun.com
http://ireland.iol.ie/~kcolfer