software failure question

software failure question

[tmoran]

Anyone know where this came from?
"In one infamous software error, a misplaced minus sign resulted in a
fighter jet's control system flipping the aircraft on its back whenever
it crossed the equator. "
http://www.newscientist.com/dailynews/news.jsp?id=ns9999595

Re: software failure question

[chris.danx]

> Anyone know where this came from?
> "In one infamous software error, a misplaced minus sign resulted in a
> fighter jet's control system flipping the aircraft on its back whenever
> it crossed the equator. "

This the article on that bloke's new system for natural language to program
code?  Sounds interesting.

Why would a misplaced minus sign result in flipping an aircraft like this?
I don't think the natural language system is going to stop errors like this.
People will still need to tell it to be wary of the equator and check for
such things.  Anyway it's unlikely that people will use it in such areas for
a long while (until it's proven reliable and correct).


My penny's worth,
Chris Campbell

Re: software failure question

[chris.danx]

Besides i don't want to graduate and find there's no programming job out
there for me.  No fancy house, no fast car, no beautiful girl on my arm.
<g>

Re: software failure question

[Mark Biggar]

tmoran@acm.org wrote:
> 
> Anyone know where this came from?
> "In one infamous software error, a misplaced minus sign resulted in a
> fighter jet's control system flipping the aircraft on its back whenever
> it crossed the equator. "

It was the fly-by-wire software for the F-16. Fortunately,
this error was caught in simulation and no planes were actually
flipped.  For more info, you might want to look in the risks-digest
report database "http://catless.ncl.ac.uk/Risks".  The bug in question
can be found easly by searching on "equator".

--
Mark Biggar
mark.a.biggar@home.com

Re: software failure question

[Larry Hazel]

Mark Biggar wrote:
> 
> tmoran@acm.org wrote:
> >
> > Anyone know where this came from?
> > "In one infamous software error, a misplaced minus sign resulted in a
> > fighter jet's control system flipping the aircraft on its back whenever
> > it crossed the equator. "
> 
> It was the fly-by-wire software for the F-16. Fortunately,
> this error was caught in simulation and no planes were actually
> flipped.  For more info, you might want to look in the risks-digest
> report database "http://catless.ncl.ac.uk/Risks".  The bug in question
> can be found easly by searching on "equator".
> 
> --
> Mark Biggar
> mark.a.biggar@home.com

And some errors like this are just simulator related.  Someone had a sign wrong
on the F4J simulator and every time the pilot stepped on the brakes while
rolling, the plane sped up.  Made landings difficult but wasn't very difficult
to find the problem.  

Larry

Re: software failure question

[Ken Garlington]

I think this is the urban legend related to the F-16. As best as I have been
able to reconstruct events, this did not happen in an F-16 in flight, but in
a ground-based F-16 flight *simulator*. Apparently, only the northern
hemisphere was programmed correctly into the simulation; when the pilot
crossed the equator, the sudden transition in reference coordinates caused
the simulation to show the pilot as inverted. You might check the RISKS
digest at

http://catless.ncl.ac.uk/Risks/18.94.html#subj14.1

for more information. (Note that there's some second-hand, obsolete, and
just plain wrong junk about the F-16 in RISKS as well, so reader beware.)

<tmoran@acm.org> wrote in message
news:9Pxz6.992$ix4.198187@news1.rdc1.sfba.home.com...
: Anyone know where this came from?
: "In one infamous software error, a misplaced minus sign resulted in a
: fighter jet's control system flipping the aircraft on its back whenever
: it crossed the equator. "
: http://www.newscientist.com/dailynews/news.jsp?id=ns9999595

Re: software failure question

[Ken Garlington]

"Mark Biggar" <mark.a.biggar@home.com> wrote in message
news:3ACF132F.95DD191A@home.com...
: tmoran@acm.org wrote:
: >
: > Anyone know where this came from?
: > "In one infamous software error, a misplaced minus sign resulted in a
: > fighter jet's control system flipping the aircraft on its back whenever
: > it crossed the equator. "
:
: It was the fly-by-wire software for the F-16.

Actually, this isn't correct. It was an error in the simulation system, not
the "fly-by-wire" embedded software.

: Fortunately,
: this error was caught in simulation and no planes were actually
: flipped.  For more info, you might want to look in the risks-digest
: report database "http://catless.ncl.ac.uk/Risks".  The bug in question
: can be found easly by searching on "equator".
:
: --
: Mark Biggar
: mark.a.biggar@home.com

Re: software failure question

[Marin David Condic]

I recall hearing of a jet engine simulation that had a similar bug with
respect to burner temperature. Apparently, the temperature could go negative
and since the scale was WRT absolute zero, air started sucking in from the
back of the engine. Naturally, this is physically impossible - but the math
for the simulation worked out that way. Given that it was, in fact, a
simulation, the error didn't hurt anything, but it is an example of how easy
it is for a minor mistake to totally botch up a system. (Something that
might have been detected more readily with strong type checking and proper
use of types/ranges.)

There are similar stories of numeric calculations which "rolled over"
mathematically causing the software to attempt to instantly reverse
mechanical actuators. This is what is known in the technical jargon as "A
Bad Thing". (Like crossing the streams! :-) A lot of these errors can easily
be caught with range checks, but before beating up on the poor Fortran
programmers who did this, remember that a range check alone won't
necessarily save the day. You have to consider the speed of the software to
determine if it can withstand range checking and you have to consider what
your FDA strategy is going to be. A bad FDA strategy (or none at all) can be
just as bad - or worse - than flipping sign bits arbitrarily.

MDC
--
Marin David Condic
Senior Software Engineer
Pace Micro Technology Americas    www.pacemicro.com
Enabling the digital revolution
e-Mail:    marin.condic@pacemicro.com
Web:      http://www.mcondic.com/


"Mark Biggar" <mark.a.biggar@home.com> wrote in message
news:3ACF132F.95DD191A@home.com...

> It was the fly-by-wire software for the F-16. Fortunately,
> this error was caught in simulation and no planes were actually
> flipped.  For more info, you might want to look in the risks-digest
> report database "http://catless.ncl.ac.uk/Risks".  The bug in question
> can be found easly by searching on "equator".

Re: software failure question

[Smark]

"chris.danx" <chris.danx@ntlworld.com> wrote in message
news:QYBz6.3604$IP5.728688@news2-win.server.ntlworld.com...
> Besides i don't want to graduate and find there's no programming job out
> there for me.  No fancy house, no fast car, no beautiful girl on my arm.
> <g>
>
>

Yeah, man, chicks dig programmers :)

I'm still waiting on the first two, but I have three beautiful girls on
my arms ...

Re: software failure question

[Phaedrus]

I'm reminded of another famous software failure, that may or
may not be an urban legend:
According to the story, when programming a helicopter simulation
for the Australian military, someone noticed that they didn't have
any kangaroos.  Rather than write a whole bunch of new code to
simulate them, they just derived a new subclass from the class that
they used to simulate the ground troops.
When they flew the new version of the simulation, the kangaroos
scattered just as expected when the helicopter flew over the hill.
But imagine their surprise when the 'roos came back and started
firing at the chopper with surface-to-air missiles!

Phaedrus
<tmoran@acm.org> wrote in message
news:9Pxz6.992$ix4.198187@news1.rdc1.sfba.home.com...
> Anyone know where this came from?
> "In one infamous software error, a misplaced minus sign resulted in a
> fighter jet's control system flipping the aircraft on its back whenever
> it crossed the equator. "
> http://www.newscientist.com/dailynews/news.jsp?id=ns9999595

Re: software failure question

[Ted Dennison]

In article <4ZmA6.1693$Ak1.181271@newsread2.prod.itd.earthlink.net>, Phaedrus
says...
>
>I'm reminded of another famous software failure, that may or
>may not be an urban legend:
>According to the story, when programming a helicopter simulation
>for the Australian military, someone noticed that they didn't have
>any kangaroos.  Rather than write a whole bunch of new code to
>simulate them, they just derived a new subclass from the class that
>they used to simulate the ground troops.
>When they flew the new version of the simulation, the kangaroos
>scattered just as expected when the helicopter flew over the hill.
>But imagine their surprise when the 'roos came back and started
>firing at the chopper with surface-to-air missiles!

I did some investigation on that one when it first made the rounds a couple of
years ago. Apparently its mostly true, except that they also didn't have a model
for the SAMs, so it used the default model, which was multicolored beach-balls.
:-)

---
T.E.D.    homepage   - http://www.telepath.com/dennison/Ted/TED.html
          home email - mailto:dennison@telepath.com

Re: software failure question

[Phaedrus]

The only thing worse than a bunch of kangaroos firing SAMs at your
helicopter is a bunch of kangaroos throwing their balls at your chopper.
;-)

Phaedrus


"Ted Dennison" <dennison@telepath.com> wrote in message
news:YmpA6.1157$FY5.85643@www.newsranger.com...
> In article <4ZmA6.1693$Ak1.181271@newsread2.prod.itd.earthlink.net>, Phaedrus
> says...
> >
> >I'm reminded of another famous software failure, that may or
> >may not be an urban legend:
> >According to the story, when programming a helicopter simulation
> >for the Australian military, someone noticed that they didn't have
> >any kangaroos.  Rather than write a whole bunch of new code to
> >simulate them, they just derived a new subclass from the class that
> >they used to simulate the ground troops.
> >When they flew the new version of the simulation, the kangaroos
> >scattered just as expected when the helicopter flew over the hill.
> >But imagine their surprise when the 'roos came back and started
> >firing at the chopper with surface-to-air missiles!
>
> I did some investigation on that one when it first made the rounds a couple of
> years ago. Apparently its mostly true, except that they also didn't have a
model
> for the SAMs, so it used the default model, which was multicolored
beach-balls.
> :-)
>
> ---
> T.E.D.    homepage   - http://www.telepath.com/dennison/Ted/TED.html
>           home email - mailto:dennison@telepath.com
>

Re: software failure question

[Marin David Condic]

Yeah. That's why *I* got into engineering - to meet girls! (I'm wondering
when that starts to happen? Is there a scheduled milestone for it? :-)

I recall this cartoon that I think was originated by Kliban but maybe was
redone by Sergio Argones in Mad Magazine. It depicts this slick looking guy
in a double breasted suit surrounded by beautiful women admiring him as he's
walking down the street. This cop is kicking this old blind guy into the
street and yelling at him: "Out of the way you swine! An *Engineer* is
coming!" (Or insert your profession as desired. Maybe I need a version that
says "Ada Programmer".) I wish I could find a copy of it in .JPG format. It
would make good wallpaper - symbolizing the high level of respect given to
those of us in the engineering professions. :-)

MDC
--
Marin David Condic
Senior Software Engineer
Pace Micro Technology Americas    www.pacemicro.com
Enabling the digital revolution
e-Mail:    marin.condic@pacemicro.com
Web:      http://www.mcondic.com/


"Smark" <not.provided@all.com> wrote in message
news:9ask6e$jgk3@cui1.lmms.lmco.com...
> >
>
> Yeah, man, chicks dig programmers :)
>
> I'm still waiting on the first two, but I have three beautiful girls on
> my arms ...
>
>
>
>

Re: software failure question

[Ted Dennison]

>In article <4ZmA6.1693$Ak1.181271@newsread2.prod.itd.earthlink.net>, Phaedrus
>says...
>>
>>I'm reminded of another famous software failure, that may or
>>may not be an urban legend:
>>According to the story, when programming a helicopter simulation
>>for the Australian military, someone noticed that they didn't have
>>any kangaroos.  Rather than write a whole bunch of new code to
>>simulate them, they just derived a new subclass from the class that
>>they used to simulate the ground troops.

I forgot about this part. The OO mumbo-jumbo that got thrown in here was just
made up. They were interfacing their virtual sim to another simulation capable
of generating and controlling other entities (perhaps MODSAF). When this is
done, each entity MODSAF is controlling needs to be mapped on the virtual sim to
an entity that the virtual sim's image generator knows how to render. Its fairly
common in such a setup to map one entity to another similar one that MODSAF (or
whatever they are using) doesn't have. I've been on two different projects that
did this. There's nothing particularly OO about it. But the story has slowly
mutated itself into some kind of unspecified object lesson on the dangers of OO
programming. Go figure.

To put my previous post in perspective, they weren't expecting SAMs to come out
of MODSAF, so they didn't set up a mapping for them. That meant they got the
default mapping, which happened to be multicolored beach balls. :-)

BTW: I've personally seen a (simulated) marine helocopter fly in close formation
with a heap of rubble for over thirty minutes due to a similar issue. We had
them keep flying that long so we could monitor the network traffic and try to
figure out where the bug was. The pilots entertained themselves during this time
by pretending that the squarish rubble heap was a Borg ship. :-)

---
T.E.D.    homepage   - http://www.telepath.com/dennison/Ted/TED.html
          home email - mailto:dennison@telepath.com

Re: software failure question

[Smark]

Luckily, I met my wife before I became a complete geek.  I can't imagine
going through all the hassles of starting a new relationship at this
point ... and I am only 30!

I recall a cartoon in, uh, another magazine, in which a guy is
surrounded by beautiful, scantily-clad women, and he looks at his
watch and says "Wait!  Wheel of Fortune is on!"  What a nerd ...
now, if "Robot Wars" was on ...

Mark

"Marin David Condic" <marin.condic.auntie.spam@pacemicro.com> wrote in message
news:9av1v3$n12$1@nh.pace.co.uk...
> Yeah. That's why *I* got into engineering - to meet girls! (I'm wondering
> when that starts to happen? Is there a scheduled milestone for it? :-)
>
> I recall this cartoon that I think was originated by Kliban but maybe was
> redone by Sergio Argones in Mad Magazine. It depicts this slick looking guy
> in a double breasted suit surrounded by beautiful women admiring him as he's
> walking down the street. This cop is kicking this old blind guy into the
> street and yelling at him: "Out of the way you swine! An *Engineer* is
> coming!" (Or insert your profession as desired. Maybe I need a version that
> says "Ada Programmer".) I wish I could find a copy of it in .JPG format. It
> would make good wallpaper - symbolizing the high level of respect given to
> those of us in the engineering professions. :-)
>
> MDC
> --
> Marin David Condic
> Senior Software Engineer
> Pace Micro Technology Americas    www.pacemicro.com
> Enabling the digital revolution
> e-Mail:    marin.condic@pacemicro.com
> Web:      http://www.mcondic.com/
>
>
> "Smark" <not.provided@all.com> wrote in message
> news:9ask6e$jgk3@cui1.lmms.lmco.com...
> > >
> >
> > Yeah, man, chicks dig programmers :)
> >
> > I'm still waiting on the first two, but I have three beautiful girls on
> > my arms ...
> >
> >
> >
> >
>
>

Re: software failure question

[Colin Paul Gloster]

It was widely reported in Spring or Summer of the year 2000. I believe
that the first time I heard about the beachballs is today. I had heard
that they actually fired (in at least one report Stinger) missiles (well,
technically beach balls can be missiles too).

Apparently it did have basis in truth but a surprisng ommission from the
commonly circulated urban legend as repeated earlier in the thread is that
" [..]The head of the Defense Science & Technology Organization's
LandOperations/Simulation division reportedly instructed developers to
model the local marsupials' movements and reactions to helicopters. [..]
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....[..] 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."

This demonstration in front of foreign officials is alleged to be the
untrue noise making the reports inaccurate. A URL I had in July 2000 with
a statement from a staff member at the department concerned pointed out
that one would expect reporters to actually ring them up to confirm that
the story is true. The URL pointed to a subdirectory of ~glen on
HTTP://WWW.QNX.com but Glen seems to have left and it is not up there now.

Colin Paul

In article <XOFA6.2036$FY5.145687@www.newsranger.com>, Ted Dennison wrote:
">In article <4ZmA6.1693$Ak1.181271@newsread2.prod.itd.earthlink.net>,
Phaedrus
>says...
>>
>>I'm reminded of another famous software failure, that may or
>>may not be an urban legend:
>>According to the story, when programming a helicopter simulation
>>for the Australian military, someone noticed that they didn't have
>>any kangaroos.  Rather than write a whole bunch of new code to
>>simulate them, they just derived a new subclass from the class that
>>they used to simulate the ground troops.

I forgot about this part. The OO mumbo-jumbo that got thrown in here was just
made up. They were interfacing their virtual sim to another simulation capable
of generating and controlling other entities (perhaps MODSAF). When this is
done, each entity MODSAF is controlling needs to be mapped on the virtual sim to
an entity that the virtual sim's image generator knows how to render. Its fairly
common in such a setup to map one entity to another similar one that MODSAF (or
whatever they are using) doesn't have. I've been on two different projects that
did this. There's nothing particularly OO about it. But the story has slowly
mutated itself into some kind of unspecified object lesson on the dangers of OO
programming. Go figure.

To put my previous post in perspective, they weren't expecting SAMs to come out
of MODSAF, so they didn't set up a mapping for them. That meant they got the
default mapping, which happened to be multicolored beach balls. :-)

BTW: I've personally seen a (simulated) marine helocopter fly in close formation
with a heap of rubble for over thirty minutes due to a similar issue. We had
them keep flying that long so we could monitor the network traffic and try to
figure out where the bug was. The pilots entertained themselves during this time
by pretending that the squarish rubble heap was a Borg ship. :-)"