Consensus algorithm based on state machine replication

So, what is a state machine?

State machine is the abbreviation of finite state automata, which is a mathematical model abstracted from the operating rules of real things.

Looking at the picture below, the door has two states, open and closed. Therefore, in my opinion, the state is a static scene, and the transition gives it dynamic changes.

By analogy, if the current data of a node is X, and now there is an operation log of add+1, then the current state is X+1, well, the state (X) has changed (operation log) Yes, this is the state machine.

Distributed consensus, in simple terms, is the whole process of reaching a consensus on the state after one or more nodes propose what a state should be.

Consensus is the process, and consensus is the result.