the perils of software re-use
Somewhat off-topic, and as likely to be urban legend as not, but
amusing . . .
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
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 detachments, 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.
The visiting Americans nodded appreciatively, but 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 simulation.
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 Americans 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
--
Prof. Richard E. Hawkins, Esq.
hawk@hawkins.cba.uni.edu
(319) 266-7114 http://eyry.econ.iastate.edu/hawk
These opinions will not be those of UNI until it pays my retainer.
Reply to: