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.

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.

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

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.

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.

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.