Research of Four-tier Design Method of Software Reliability

The paper introduced development process of software bug, software defect, software fault and software failure, and put forward corresponding four-tier design methods of software reliability, including error avoided design, error checked design, error corrected design and fault-tolerant design. In view of the development process of software error from occurring to failure, the design method captures software error as early as possible in order to prevent error from developing. The method can improve reliability of application software radically.