Opening up the Verification and Validation of Safety-Critical Software

Abstract

Commercial realizations of ETCS have not yet fulfilled the expectation of enabling smooth cross-border rail traffic. Starting from the hypothesis that the traditional way of developing software for safety-critical systems might be partly causing these problems, the ITEA~2 project openETCS has set out to pursue the idea of transferring an open-source development style to this domain, taking the EVC as a case study. The goal is to formalize the requirements in a functional model, derive, via design models, an implementation, and demonstrate how the verification and validation activities necessary for certifying the result could be performed. All of this is to be done as an open-source project, employing only open-source tools. One of the main motives behind the approach is to use the potential of an open community to detect design and implementation flaws much better than the limited inspection in a traditional development setting. This papers discusses the challenges this new approach faces from the legal requirement of adhering to the standards, mainly the EN 50128 in this case, particularly with respect to verification and validation. This comprises the interpretation of the standard for a model-based development and qualification issues for personnel and tools.