Functional Redundancy Checking

Hi,

I'm wondering if anyone can give me a rough idea of how many systems
use Functional Redundancy Checking with Intel CPUs, and what sorts of
systems they are.

For example, is FRC used by Intel's internal quality control only, or
is it used by some (rare) special purpose systems (aviation?), or is it
perhaps used a lot more often where high reliability is desirable
(banks, datacenters, etc)....

For "bonus points", do any of these systems use more than 2 CPUs, so
that recovering from a detected failure is possible?


Thanks,

Brendan