The Research Framework for Quantitative Safety Assessment for Safety-Critical Computer Systems

Objectives: A safety-critical computer system has to be designed with safety in mind. The purpose of this paper is to identify and assess the safety hazards by using the proposed framework for Safety-Critical Computer Systems (SCCS). Methods/Statistical Analysis: Computer software quality models like McCall’s and Boehm’s were deficient in addressing the basic safety issues of SCCS. This paper proposes another safety model for software safety by adjusting McCall’s product quality model that particularly distinguishes the conditions comparing to software safety in safety-critical applications. The conditions in the proposed software safety model relate to Hazard Analysis distinguishing of Completeness of safety requirements, Safety-critical Design, Coding, and Testing. Findings: The criteria in the proposed software safety model relate to Hazard Analysis (HA) distinguishing of safety requirements, Completeness of safety requirements, Safety-critical Design, Safety-critical Coding, and Safety-critical Testing. The proposed safety model changes the current quality model by presenting different safety criteria’s and metrics in all phases of Software life cycle to assess the software safety. This model was connected to a safety basic Railroad Crossing Control System (RCCS) which is a laboratory prototype and obtained better results in terms of safety. Application/Improvements: This model was connected to a safety basic Railroad Crossing Control System (RCCS) which is a laboratory prototype and obtained better results in terms of safety.