Softwares is becoming increasingly important causes for failures of safety programmable electronic (PE) systems,PRA and CSRM both take it as an important risk contributor and respectively access risk of systems and software in system level.However they partly identify software-related risk scenarios ,and can’t tell what a software must do about all safety-critical conditions,i.e.,safety functions,especially warning functions for conditions software can’t control but must alarm operators to action immediately.Here we give a method to find all software-related safety-critical scenarios,through it all safety-critical conditions and the corresponding functions can be identified.
