Date:         Fri, 3 Dec 1999 23:02:23 -0800
Reply-To:     Austin <austins@IX.NETCOM.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Austin <austins@IX.NETCOM.COM>
Subject:      Friday
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#1 former rugrat sent me the following:


before you get carried away by the object-oriented features of Ada 95,
consider this...


Subject: CARELESS CODE RECYCLING CAUSES 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 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.

Austin