Re: Error detection
The approach adopted by Tandem Computers was to duplicate everything - including memory and persistent storage -- as you can get bus glitches, cache glitches and all sorts of other transient faults in "shared" components which you would not otherwise be able to detect simply from core coupling. But even that doesn't necessarily protect against systematic errors where every instance of (say) the processor makes the same mistake repeatably.
It's a difficult problem: and don't forget that many peripherals will also have processors in them, it's not just the main CPU you have to look out for.
Biting the hand that feeds IT
