What is the three-input majority function, and how does it operate?

Question

Please give as much detail as possible.

Answer 1

It is a decision node having three inputs and one output. The output is set to the majority vote: at least 2 of the 3 input values must agree.

Its principal use is in fault-tolerance systems. It improves reliability by enabling the system to tolerate one of the three independent redundant components to fail during critical mission time.

By the way, such a node is not limited to tolerating hardware failures. For example, certain U.S. avionic systems are required to have control decisions confirmed by majority votes of the computation results of three software threads developed independently and run independently on three separate flight computers.