An Application-Specific Real-Time Operating System Towards Safety-Critical Requirements: a Case Study

Novel technologies are continuously being introduced and causing a paradigm shift in people’s lives. Vehicles like an electric vertical take-off and landing (eVTOL) are remarkable examples. They are classified as safety-critical systems, as they can lead to severe material or human losses, in case of malfunction. At the same time, the pressure for cost reduction due to high volumes expected to be produced may bring a disruption in the way avionics are developed so far. In the software aspect, for instance, the use of commercial-grade real-time operating systems (RTOS) may be replaced by open-source ones in the lower criticality level software items. However, although there are free and open-source software (OSS) promptly available, most of them are not designed based on evidence and quality levels expected by a safety standard, which makes it difficult to adopt them in conservative domains such as aerospace. In this context, we propose an extension of our previous research: a methodology to transform an OSS into an application-specific RTOS for safety-critical purposes. Our proposal differs from others by the fact that it is a straightforward design guideline, counting on formal modeling techniques to strengthen fundamental concepts in the design flow. Finally, we provide an illustrative example based on input requirements for an avionics subsystem to show the potential and applicability of our proposed methodology.