This diagram outlines the different states of a finite state machine, a type of computing system that uses a set of predetermined states to process data. It shows the different states that the machine can be in, the transitions between them, and the inputs and outputs associated with
From Wikipedia
A state diagram is used in computer science and related fields to describe the behavior of systems. State diagrams require that the system is composed of a finite number of states. Sometimes, this is indeed the case, while at other times this is a reasonable abstraction. Many forms of state diagrams exist, which differ slightly and have different semantics.