Re: "triggers an exception that can't be handled and the CPU halts"
>I'm pretty sure that if the CPU halts it will be rebooted pretty sharpish.
'In simulator tests, government pilots discovered that a microprocessor failure could push the nose of the plane toward the ground. It is not known whether the microprocessor played a role in either crash.'
I suspect the 'revised' tests force a processor STOP, just to see what happens. Unfortunately, what happens is an aircraft STOP. Hence multiple redundant systems. I bet no tests like that have been done before on this system.
Watchdogs: I've seen a tickle done from a timer interrupt handler. And for his Full Gold Star, the engineer actually claimed he was being clever.
>When I was working with people writing diesel engine controllers 15 years ago
A lot's changed in 15 years, and none of it good.