"Paul" wrote in message
...

As for the $20,000,000 planes don't they have more than one computer for
all
the main systems with the software written by different companies, and the
computers keep a check on each other to make sure they are both working.

IIRC they have three computers and they vote by majority.

N

"Paul" bravely wrote to "All" (12 Jul 05 16:17:47)
--- on the heady topic of " Weird Microwave problem - trips breaker when you
shut the door!"

Pa From: "Paul"
Pa Xref: aeinews sci.electronics.repair:53019

Pa Note that the Therac25 was developed from an earlier machine which had
Pa mechanical interlocks and when you pressed the same combination of
Pa back spaces did blow a fuse, possibly 100's of people where over
Pa exposed from what I remember and several fatally or damaged for life.
Pa Do you remember in the 80's or 90's when people where installing there
Pa own mobile phones in cars and where being warned it could mess up the
Pa ABS and engine management causing accidents.
Pa Then there was the F*rd Probe car which had a problem with the ECU
Pa which meant interference from the ignition system could cause it to
Pa accelerate out of control, a man was killed when his car flew off an
Pa off ramp at over a 120 miles and hour into trees.
Pa As for the $20,000,000 planes don't they have more than one computer
Pa for all the main systems with the software written by different
Pa companies, and the computers keep a check on each other to make sure
Pa they are both working.

Paul,

They do but they still manage to rip rudders off airplanes when the
pilot only moves the pedals 1-1/2 inches, like happened in New York
about a month after 9/11/2001. Just because software is in charge
doesn't mean it isn't safe. The problem is always GIGO and unless
inputs are properly validated then all hell will and does break loose.
Why don't software engineers get it already?

A*s*i*m*o*v

.... Bald spot? It's a solar panel for a sex machine.

"Asimov" writes:

"Paul" bravely wrote to "All" (12 Jul 05 16:17:47)
--- on the heady topic of " Weird Microwave problem - trips breaker when you
shut the door!"

Pa From: "Paul"
Pa Xref: aeinews sci.electronics.repair:53019

Pa Note that the Therac25 was developed from an earlier machine which had
Pa mechanical interlocks and when you pressed the same combination of
Pa back spaces did blow a fuse, possibly 100's of people where over
Pa exposed from what I remember and several fatally or damaged for life.
Pa Do you remember in the 80's or 90's when people where installing there
Pa own mobile phones in cars and where being warned it could mess up the
Pa ABS and engine management causing accidents.
Pa Then there was the F*rd Probe car which had a problem with the ECU
Pa which meant interference from the ignition system could cause it to
Pa accelerate out of control, a man was killed when his car flew off an
Pa off ramp at over a 120 miles and hour into trees.
Pa As for the $20,000,000 planes don't they have more than one computer
Pa for all the main systems with the software written by different
Pa companies, and the computers keep a check on each other to make sure
Pa they are both working.

Paul,

They do but they still manage to rip rudders off airplanes when the
pilot only moves the pedals 1-1/2 inches, like happened in New York
about a month after 9/11/2001. Just because software is in charge
doesn't mean it isn't safe. The problem is always GIGO and unless
inputs are properly validated then all hell will and does break loose.
Why don't software engineers get it already?

Remenber the Airbus A320? that crashed at its maiden airshow appearance?
That wsa a software bug.

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"Asimov" wrote in message
...

They do but they still manage to rip rudders off airplanes when the
pilot only moves the pedals 1-1/2 inches, like happened in New York
about a month after 9/11/2001. Just because software is in charge
doesn't mean it isn't safe. The problem is always GIGO and unless
inputs are properly validated then all hell will and does break loose.
Why don't software engineers get it already?

"If builders built buildings the way programmers wrote programs, then the
first woodpecker that came along would destroy civilization".

-- Weinberg's Second Law

N

"Sam Goldwasser" bravely wrote to "All" (12 Jul 05 20:05:45)
--- on the heady topic of " Weird Microwave problem - trips breaker when you =
shut the door!"

SG From: Sam Goldwasser
SG Xref: aeinews sci.electronics.repair:53055

SG "Asimov" writes:

Why don't software engineers get it already?

SG Remenber the Airbus A320? that crashed at its maiden airshow
SG appearance? That wsa a software bug.

Sure do. The program kicked in the thrust reversers because it thought
it had already landed. Faulty input or bad coding? Take your pick but
the problem was the inputs weren't properly validated and the program
jumped into a state that was obviously, to a human at least, wrong to
be in. A program should never be able to jump into wrong states out of
sequence like that. Just stupid!

A*s*i*m*o*v

.... First Church of Binary Science (The Digitarians)

"NSM" bravely wrote to "All" (13 Jul 05 00:29:45)
--- on the heady topic of " Weird Microwave problem - trips breaker when you
shut the door!"

NS "If builders built buildings the way programmers wrote programs, then
NS the first woodpecker that came along would destroy civilization".

NS -- Weinberg's Second Law

Love that quote!

A*s*i*m*o*v

.... Programmer(n): One who makes the Salesman's lies reality

Sure do. The program kicked in the thrust reversers because it thought
it had already landed. Faulty input or bad coding? Take your pick but
the problem was the inputs weren't properly validated and the program
jumped into a state that was obviously, to a human at least, wrong to
be in. A program should never be able to jump into wrong states out of
sequence like that. Just stupid!


I would tend to blame the hardware there. Traffic signal controllers have
conflict monitors which are separate devices which monitor the outputs to
the lights and in the event of greens in multiple directions will trip the
system offline and put it in 4 way flash.