a method of generating a heartbeat signal for an application comprising one or more objects that may enter a halt state is described . the method comprises : sending a status request to a defined interface on each object ; and monitoring responses to the status requests to ascertain if each object is operating normally or in a halt state . the method further comprises : generating an application valid signal in the event that each object is operating normally ; transmitting the application valid signal , if generated , to a monitoring component independent of the application ; and generating at the monitoring component a heartbeat valid signal in response to receipt of the application valid signal .