Safety-related Systems —
Functional Safety in Software —
The End of Deterministic Systems —
Functional Safety with SOUP —
Conclusion
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Introduction
In the context of the present discussion, we consider that a safety-related system is a system that could cause unacceptable or unforeseen injury or damage to the health of people, or damage to property or the environment, but that operates in a way ...
Functional Safety in Software
Software has been employed in safety-related systems for generations. It has become ubiquitous in contexts ranging from oil refineries to medical devices to automobiles to spacecraft. In every one of these implementations the software systems — like the larger systems in which they operate — have undergone rigorous ...
The End of Deterministic Systems
More significant than the assumption that software does not wear out is the assumption that a safety-related software system is deterministic, that every state and state transition in the system can be known and tested. This assumption was largely valid for software systems in the past, and ...
Functional Safety with SOUP
If we accept, first, that safety-related systems will increasingly require more interaction and computing power than can be provided by single-threaded, run-to-completion systems, and, second, that complex, multi-threaded software systems cannot be validated for functional safety through exhaustive testing, then it becomes essential to map out ...
Conclusion
We have seen that the functional safety of today’s multi-threaded complex software systems cannot be validated by traditional, state-based testing alone. Though these systems are deterministic in theory, due to the number of possible states and state transitions they can present, they might as well be infinite. ...
