IP: UNINTENDED CONSEQUENCES OF CODE RECYCLING

[Dave Farber <farber@cis.upenn.edu>]

>
>From: Charles W. Whetsel
>Sent: Tuesday, December 07, 1999 8:25 PM
>Subject: UNINTENDED CONSEQUENCES OF CODE RECYCLING
>
>  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