CARELESS CODE RECYCLING CAUSES KILLER KANGAS
Mutant Marsupials Take Up Arms Against Australian Air Force
The reuse of some object-oriented code has 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 marsupials' movements and reactions to helicopters.
Being efficient programmers, they just re-appropriated 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 hapless 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
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Pongo
Sturm Gruppe
