摘要
One of the significant differences between the digital system and the analog system is software. The software takes charge of the functions and the management of the digital system. Nowadays railway equipment has begun to be designed and implemented based on digital technology with online and real time performance to achieve high speed and high density operation. The software is designed, coded and implemented into the system, and controls hardware components in order to satisfy the functional requirements of the system. As the functions that are implemented by software are increased, it becomes very difficult to predict the soil-ware failures because of its complexity. Therefore, it has become one of the key issues how to assure that the sottware is reliable, safe and secure. In this paper, the safety criteria are suggested to secure the software safety for the field of railway system. Characteristic of railway software and review safety related standards are analyzed. The authors also suggest development methodology and certification procedure for the developer and assessor to easily make safety critical railway software with following the safety criteria.
