Comment by simne

> how do you avoid the voting circuit becoming a single point of failure

They do not. Just make voting circuit much more reliable than computing blocks.

As example, computing block could be CMOS, but voting circuit made from discrete components, which are just too large to be sensitive to particles.

Unfortunately, discrete components are sensitive to overall exposure (more than nm scale transistors), because large square gather more events and suffered by diffusion.

Other example from aviation world - many planes still have mechanic connection of steering wheel to control surfaces, because mechanic connection considered ideally reliable. Unfortunately, at least one catastrophe happen because one pilot blocked his wheel and other cannot overcome this block.

BTW weird fact, modern planes don't have rod physically connected to engine, because engine have it's own computer, which emulate behavior of old piston carburetor, and on Boeing emulating stick have electronic actuator, so it automatically placed in position, corresponding to actual engine mode, but Airbus don't have such actuator.

I want to say - especially big planes (and planes overall), are weird mix of very conservative inherited mechanisms and new technologies.