Boeing 737 Max software fix fails... again

[Clifford Heath]

Just when you thought it was safe to fly again...

<https://www.theregister.co.uk/2019/06/27/boeing_737_max_control_bug_found/>

It make me think that every time you add code to close a loop-hole, you
open new, smaller loopholes around the boundaries.

Clifford Heath.

 

[bitrex]

On 6/26/19 9:04 PM, Clifford Heath wrote:

Just when you thought it was safe to fly again...

https://www.theregister.co.uk/2019/06/27/boeing_737_max_control_bug_found/


It make me think that every time you add code to close a loop-hole, you
open new, smaller loopholes around the boundaries.

Clifford Heath.

"To us, it sounds as though code in the MCAS update either forces the
processor into a locked state, such as a tight unbreakable and
uninterruptable infinite loop, or triggers an exception that can't be
handled and the CPU halts. It is remotely possible the code encounters a
design flaw in the unidentified microprocessor that causes the circuitry
to freeze."

great news though the Register has managed to remote-diagnose the
problems Boeing should hire them.

 

[Tom Gardner]

On 27/06/19 02:04, Clifford Heath wrote:

Just when you thought it was safe to fly again...

https://www.theregister.co.uk/2019/06/27/boeing_737_max_control_bug_found/

It make me think that every time you add code to close a loop-hole, you open
new, smaller loopholes around the boundaries.

That is a far from uncommon occurrence in complex systems,
especially ones which operate in different "modes".

Whether that is what happened in this case is unclear.

 

Tom Gardner <spamjunk@blueyonder.co.uk> wrote in
news:X3_QE.74180$rV5.19243@fx19.am4:

On 27/06/19 02:04, Clifford Heath wrote:
Just when you thought it was safe to fly again...

https://www.theregister.co.uk/2019/06/27/boeing_737_max_control_b
ug_found/

It make me think that every time you add code to close a
loop-hole, you open new, smaller loopholes around the boundaries.

That is a far from uncommon occurrence in complex systems,
especially ones which operate in different "modes".

Whether that is what happened in this case is unclear.

It also means that the fault that caused the crashes may have been
twofold.

 

[Martin Brown]

On 27/06/2019 02:04, Clifford Heath wrote:

Just when you thought it was safe to fly again...

https://www.theregister.co.uk/2019/06/27/boeing_737_max_control_bug_found/


It make me think that every time you add code to close a loop-hole, you
open new, smaller loopholes around the boundaries.

Especially when you are doing it in a hurry and in the full glare of bad
publicity. I feel for them if they have uncovered a latent CPU defect.

Changing any complex piece of software you can get unwanted side
effects. These vary from slight timing differences to full on lock ups.

Sometimes cosmetic faults are just not worth fixing...
eg. the IBM FORTRAN G1 compiler of old which would print out

NO DIAGNOSTICS GENERATED?

With a trailing nul because someone couldn't count and the process for
fixing it was too arduous and expensive for a trivial cosmetic defect.

--
Regards,
Martin Brown

 

[Tom Gardner]

On 27/06/19 10:40, DecadentLinuxUserNumeroUno@decadence.org wrote:

Tom Gardner <spamjunk@blueyonder.co.uk> wrote in
news:X3_QE.74180$rV5.19243@fx19.am4:

On 27/06/19 02:04, Clifford Heath wrote:
Just when you thought it was safe to fly again...

https://www.theregister.co.uk/2019/06/27/boeing_737_max_control_b
ug_found/

It make me think that every time you add code to close a
loop-hole, you open new, smaller loopholes around the boundaries.

That is a far from uncommon occurrence in complex systems,
especially ones which operate in different "modes".

Whether that is what happened in this case is unclear.


It also means that the fault that caused the crashes may have been
twofold.

The proximate cause maybe.

Underlying common causes could be different.

 

[Lasse Langwadt Christense]

torsdag den 27. juni 2019 kl. 03.33.51 UTC+2 skrev bitrex:

On 6/26/19 9:04 PM, Clifford Heath wrote:
Just when you thought it was safe to fly again...

https://www.theregister.co.uk/2019/06/27/boeing_737_max_control_bug_found/


It make me think that every time you add code to close a loop-hole, you
open new, smaller loopholes around the boundaries.

Clifford Heath.

"To us, it sounds as though code in the MCAS update either forces the
processor into a locked state, such as a tight unbreakable and
uninterruptable infinite loop, or triggers an exception that can't be
handled and the CPU halts. It is remotely possible the code encounters a
design flaw in the unidentified microprocessor that causes the circuitry
to freeze."

great news though the Register has managed to remote-diagnose the
problems Boeing should hire them.

the real story seems to be rather different

https://youtu.be/isy9yAU6ajQ