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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