Objective Measurement of Safety in the Context of IEC 61508-3

Abstract

Safety standards like the IEC 61508 are an important source for developing safety-critical (software) systems as they provide a set of requirements and recommendations to assist engineers in system and software development. Applying this standard in practice leads to interpretation problems due to insufficient operationalization, i.e. unclear requirements and unclear or missing acceptance criteria. This makes it hard to measure the extent to which a product fulfills the requirements of the standard.For this, we systematically developed a quality model that covers the coding-related parts of the safety standard IEC 61508. It provides refinements to the recommendations and equips them with proper measurement support by means of static code analysis tools (236 measures for C/C++ systems).We found in an evaluation study that the used approach is suitable for covering the coding-related parts of the standard with proper and meaningful operationalization. Additionally, the results indicate an adequate completeness of the modeled contents. This encourages us to go a step further and to extend the model to support compliance assessments in future work.

Measuring, Assessing and Improving Software Quality based on Object-Oriented Design Principles

“…Authors of this paper were part of the Quamoco development team and already developed Quamoco-based quality models for embedded systems [28], safety critical systems [29] and for software documentation quality [30]. Quamoco-based quality models rely on the basic idea of using product factors for expressing a quality property of an entity.…”

Objective safety compliance checks for source code

“…Based on our previous works on software quality modeling (e.g., the Quamoco base model [26] and embedded software quality model (ESQM) [21]), we developed SAQE [20] to capture the requirements of the software-related parts of the IEC 61508 safety standard. Modeling the specific parts of the standard related to software implementation enabled us (1) to specify the as-is state of coding requirements and techniques and (2) to add necessary refinements in order to make these specific parts measurable by using static analysis techniques.…”

“…For this, we associated these refinements with measures of static code analyzers for the programming languages C and C++. In [20], we focused on describing the systematic modeling process for SAQE and core meta-model elements needed for this purpose. Additionally, we provided a completeness evaluation of the covered techniques.…”

“…On the basis of our previous work on the safety quality model SAQE [20], the contribution of this work is (1) a comprehensive extension of SAQE that provides an approach to systematically assess software products regarding the code-related techniques and recommendations of IEC 61508 and (2) an empirical validation with real-world projects of the entire SAQE approach.…”

“…Nevertheless, applying this standard in practice is difficult due to unclear requirements and unclear or missing acceptance criteria. We systematically developed a quality model including proper measurement support that covers the coderelated parts of IEC 61508 in [20]. In this paper, we present the assessment approach for automatic compliance checks of the code-related parts of the standard.…”