Simulators

All simulators have the same four components,

An internal model of the world or part of it; for example a model of a vehicle travelling through a model geography, or a model of the physical state of a nuclear power plant.
External devices to display the state of the model; for example, one or more video displays, audio speakers, or a simulated instrument panel.
External devices to supply control inputs; for example a steering wheel, a joystick, or simulated knobs and dials.
An operator (or hardware under test) that "closes the loop" by moving the controls in response to what is shown on the display.