Execution_InteractivCalculator is used interactively.Execution_RunningCalculator running a program.Execution_HaltCalculator debugging a program.Execution_PauseCalculator pauses for a sec.Execution_1_StepDo a single step and return to Execution_Halt.Execution_WriteCalcluator is in write program mode.Execution_ClearCalcluator is in clear memory mode.Execution_Alpha_PauseInitial pause when alpha starts scrolling.