Reply to post: Re: Two cores? How do you know which one is wrong?

Take the wheel, Arm tells its notebook-grade Cortex-A76 CPU: Now you're a robo-ride brain


Re: Two cores? How do you know which one is wrong?

There has to be at least three to allow recovery. It doesn't matter if that is three copies of the processor, or three copies of a control variable in RAM.

I've programmed systems where there are 4 copies, just to be extra sure, as it's highly unlikely that two copies will fail in exactly the same way, but if two were to fail in differing ways (with modern, ever smaller geometry memory devices or processors, a cosmic ray can run through many gates) then you still get a consensus.

These days Size, Weight and Power (SWaP) is king in most applications, so multicore is the way even mission critical systems are going.

8 cores on your device, then have 4 in lock step performing one algorythm, and the other 4 also in lock step performing a different implementation of the same high level requirements. (Duplicate, non-identical, versions to mitigate against coding errors.)

Run a high integrity RTOS e.g. DO178C DAL-A certified multicore VxWorks 653 and Robert is your uncle.

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