Earlier quoted context omitted.
I have a friend that used to do embedded programming for nuclear power plants. From what he said they have 5 systems, two running software from vendor a, two from vendor b, and another running software from vendor c for failsafe. A quorum have to agree, if any don't it gets pulled out of service and analyzed why it wasn't the same output. If you get down to one there is still a mechanical failover but at that point y…
Who writes the software for the quorum? Or is it hardware?
Sorry for the later reply, basically all the devices communicate with each other and the odd one out voluntarily powers off or gets powered off by the rest.