I am looking at register machines like the Random Access Machine. Wikipedia says:
Random-access machine (RAM) – a counter machine with indirect addressing and, usually, an augmented instruction set. Instructions are in the finite state machine in the manner of the Harvard architecture.
Does this mean the instructions are somehow encoded as a finite automaton? Or how exactly is a register machine implemented (theoretically and practically, at a high level). Where do automata fit into the picture?
I am wondering because I realize automata are pretty limited in what they can do, and once you need to "parse" something but have access to an entire database of information at each step of the parse, and then the result of parsing is a complicated object graph, you are no longer dealing with automata (as far as I can tell). Automata are basically recognizers returning a yes or no answer, with very little access to "data" to make their transition decisions. But I like the idea of "state machine", where it transitions around state to state.
So I'm wondering what a so-called "state machine" with access to a large database to figure out how to make each transition might be called, and if this is what a register machine could/would be.
My understanding is that a complex register machine is closer to something like x86, where you have instructions and data. But it seems that you might somehow be able to encode these instructions as a state machine somehow. Is this true? What am I missing from this picture? Is a register machine compiled down to automata of some sort, or otherwise built out of automata, or if not, how is it different from automata?