A frequent system requirement is the automatic resumption of work after a disturbance/disruption. It can be useful to record the state of a system at shut down and to save the data in a non-volatile memory. At startup the system can evaluate if the system restarts due to disturbance or failure (warm start), and the system status can be restored or an error can be indicated. In case of a cold start, the saved data in the memory can be considered valid.