Safety Assessment of Computer Interlocking Software Systems for a Typical Railway Station
Wang Tie-jiang · Journal of the China Railway Society · 2004
Computer Interlocking Software (IS) is the most complicated and safety-demanding software in railway signal computer control systems. Offering product licenses after mode testing is an important measure of the Ministry of Railways to improve interlocking quality administration. Through safety evaluation on interlocking software by mode testing, information about software developer's ability to understand safety problems and thus process them can be obtained in order to make up for the insufficient evaluation of “qualified” or “unqualified”. This paper firstly defines a safety index based on seriousness and probability of each safety problem (i.e. software fault). Thereafter, the safety evaluation standard i.e. IS safety problem complete solving on mode testing is put forward to reflect developing level. This paper consists of evaluation model, method, and proof about mapping consistence from the experience relation system to the numerical value relation system. In the end of the paper, some finished IS mode testing are evaluated and the results are listed.