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 Defence Science & Technology Organisation'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 Defence Science and Technology Organisation
Lecture Series, Melbourne, Australia, and staff reports