Killer Kangaroos


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 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. Item appeared in Software Testing and Quality 
Engineering magazine, Volume 1, Issue 6 (November/December 
1999).