General > General Technical Chat
Another deadly 737 Max control bug just found!
SiliconWizard:
--- Quote from: David Hess on July 26, 2019, 01:38:01 pm ---We found an bug in the IP stack of Windows 2000 which slowly leaked memory requiring a reboot about every 2 weeks on a low memory system. Microsoft's only recommendation was to install more memory and they never fixed it.
--- End quote ---
Is that what we call being "practical"? ;D
SiliconWizard:
--- Quote from: David Hess on July 18, 2019, 03:23:43 am ---How complex does a system involving physical control loops need to be? Separate it and stick it on redundant hardware.
Static allocations are wasteful but so what? Memory is cheap.
--- End quote ---
Yeah I agree. Control loops in avionics are still based on pretty simple algorithms. No need for any dynamic allocation.
MISRA-C is clear about that.
https://www.misra.org.uk/forum/viewtopic.php?t=1233
I believe the rules are, or at least should reasonably be the same in avionics software.
If using dynamic allocation, you would at least have to justify that thoroughly. So I'm wondering what kind of arguments could be used here.
I know some teams heavily rely on automated tools (such as dynamic code analysis), so that if the tools don't catch any potential memory leak, the team considers the code OK. That gives them a feeling of a safety net and gives them the possibility of using dynamic allocation without having to think twice about it (thinking the tools will catch all problems). This is bad.
On a general level, following no or fewer rules just because there are machines or people that are going to check an engineer's work is a recipe for bad design...
StillTrying:
UK TV tomorrow night.
Boeing's Killer Planes
Panorama
The Boeing 737 Max was set to dominate the skies, but two deadly crashes have left the aircraft grounded and the company in crisis. Both flights were forced down by software specially designed for the new aircraft. Reporter Richard Bilton investigates the plane’s fatal flaws and asks whether Boeing should have done more to protect passengers.
https://www.bbc.co.uk/programmes/m00077cw
MT:
How did that tittle even pass BBC program board executives? ;D BBC seams desperate these days yet again connected to pedophilia and all!
Towger:
The BBC culture of old appears to have been left behind in London when it sold up and moved to Manchester.
I am sure Trump will have an interesting tweet about the program...
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