ABSTRACT
There are several questions that have to be answered when considering software development of safety-critical solutions-in our case-railway systems. One of the first would be to better understand the status of software development
1 INTRODUCTION
Railway systems are becoming increasingly more based on software and relatively less on hardware, which becomes more powerful, standardized and flexible. This creates new opportunities and challenges for system providers as well as certification bodies. Software is by nature different from hardware as it is far more flexible and changeable. This is reflected in requirements management and development where software can be changed and tested more frequently than hardware design and implementation. Based on frequent testing and interaction with the system owner and its users, requirements can potentially be adjusted more frequently, creating both challenges and opportunities. This change has led to the introduction of agile software development methods in development and certification of safety critical systems [2, 4]. These methods promise reduced lead-time, reduced development costs and more flexibility in requirements management and development, however there are also some new challenges that need attention. In particular, certification and proof of compliance with safety standards becomes a challenge.
