One Formalized Method of Research on the Transformation Rules between Software Reliability and Safety

In one software system, the software’s reliability and safety are ultimately determined by the program operating states, which will be changed as the exterior and interior environment changing. in this paper, according with the environmental factor which lead to the changing of program states, the definition of the deviation loss caused by the changing of program states is presented, and in some conditions is proposed ? the formal method is used to describe the transition rules between the software reliability and safety. Finally, the formal proofs of these rules are given.