* Code reuse: a cautionary tale
@ 1999-12-08 0:00 John English
1999-12-09 0:00 ` Ted Dennison
0 siblings, 1 reply; 3+ messages in thread
From: John English @ 1999-12-08 0:00 UTC (permalink / raw)
This floated past me the other day, and I thought the folks in this
group might be as amused by it as I was...
-- From June 15, 1999 Defense Science and Technology Organization
Lecture Series, Melbourne, Australia, and staff reports
CARELESS CODE RECYCLING CAUSES KILLER KANGA'S
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.
-----------------------------------------------------------------
John English | mailto:je@brighton.ac.uk
Senior Lecturer | http://www.it.bton.ac.uk/staff/je
Dept. of Computing | ** NON-PROFIT CD FOR CS STUDENTS **
University of Brighton | -- see http://burks.bton.ac.uk
-----------------------------------------------------------------
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* Re: Code reuse: a cautionary tale
1999-12-08 0:00 Code reuse: a cautionary tale John English
@ 1999-12-09 0:00 ` Ted Dennison
1999-12-13 0:00 ` John English
0 siblings, 1 reply; 3+ messages in thread
From: Ted Dennison @ 1999-12-09 0:00 UTC (permalink / raw)
In article <384E4D56.8BD3A9FE@bton.ac.uk>,
John English <je@bton.ac.uk> wrote:
> This floated past me the other day, and I thought the folks in this
> group might be as amused by it as I was...
In fact, as someone who has worked on simulators for about 5 years, I
was so amused when I saw it yesterday, that I went on a hunt to find its
source. Thank goodness for alt.folklore.urban!
--------------------------------
From: CL Ku <reallife@mail.utexas.edu>
Subject: Re: kangas that shoot back
Date: 06 Dec 1999 00:00:00 GMT
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>this sounds a bit bogus to me, but i can't find any evidence
>one way or the other. i did find a few notes that it had
>"been around" for a few years on deja.com, but no cites.
>can anyone here help?
> > CARELESS CODE RECYCLING CAUSES KILLER KANGAS
The article you quoted appeared here:
http://defence-data.com/archive/page5926.htm
For the conclusion (and real story), go here:
http://defence-data.com/archive/page5933.htm
-------------------------------------------------------
It turns out that:
* It had next to nothing to do with OO code reuse. MODSAF is a very
commonly used stand-alone entity generator. Every virtual sim networked
to a MODSAF simulator will have to map MODSAF (or DIS) model IDs to
their own limited set of visually-displayable models. It is quite common
in the simulator world to use (hack) this function to remap entities to
something completely different than what MODSAF thinks they are.
I can recall a similar situation on a trainer I worked on where we ended
up with 3 piles of rubble flying in formation for about 30 minutes while
we tried to track down the problem. The pilots amused themselves during
that time by pretenting they were Borg cubes. :-)
* The kangaroos didn't really fire stingers, they threw beach-balls.
:-)
--
T.E.D.
Sent via Deja.com http://www.deja.com/
Before you buy.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Code reuse: a cautionary tale
1999-12-09 0:00 ` Ted Dennison
@ 1999-12-13 0:00 ` John English
0 siblings, 0 replies; 3+ messages in thread
From: John English @ 1999-12-13 0:00 UTC (permalink / raw)
To: Ted Dennison
Ted Dennison wrote:
> In article <384E4D56.8BD3A9FE@bton.ac.uk>,
> John English <je@bton.ac.uk> wrote:
> > This floated past me the other day, and I thought the folks in this
> > group might be as amused by it as I was...
>
> In fact, as someone who has worked on simulators for about 5 years, I
> was so amused when I saw it yesterday, that I went on a hunt to find its
> source. Thank goodness for alt.folklore.urban!
And thank you for the legwork on this:
> For the conclusion (and real story), go here:
> http://defence-data.com/archive/page5933.htm
I'd assumed it was an urban myth, but it certainly made me laugh
anyway!
> I can recall a similar situation on a trainer I worked on where we ended
> up with 3 piles of rubble flying in formation for about 30 minutes while
> we tried to track down the problem. The pilots amused themselves during
> that time by pretenting they were Borg cubes. :-)
ROFL!
-----------------------------------------------------------------
John English | mailto:je@brighton.ac.uk
Senior Lecturer | http://www.it.bton.ac.uk/staff/je
Dept. of Computing | ** NON-PROFIT CD FOR CS STUDENTS **
University of Brighton | -- see http://burks.bton.ac.uk
-----------------------------------------------------------------
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