Safety Analysis for Safety-Related Software Based on a Fault Detection Count Model

摘要

IEC 61508 is widely known as the international standard for the functional safety of electrical/electronic/programmable electronic (E/E/PE) safety-related systems. Especially for the hardware of E/E/PE safety-related systems, IEC 61508 requires to assess their safety based on the safety integrity level (SIL) measured by the target failure measures. However, IEC 61508 does not give us the methodologies on quantitative safety assessment for the E/E/PE safety-related system software because the software failure is treated as a systematic failure. We discuss approximated methods for estimating target failure measures, which are basic measures for allocating SIL, for SIL-based software safety assessment by applying the technical notions of software fault detection count model in software reliability assessment technologies.