'StopTime' is set to 'inf', which allows the simulation to run until you manually stop it by selecting Stop from the Simulation menu or by pressing the Stop Simulation button on the toolbar. To set a finite stop time, enter a value for the Stop time parameter in the Simulation Parameters dialog box.
'Solver' is set to 'fixedstepdiscrete', which selects the fixed-step solver option instead of Simulink's default variable-step solver. See "Discrete-Time Signals in Simulink" in the next section for more information about the various solver settings.