Meaning
Isolated hardware or software component that enforces the fundamental security and safety constraints of a system. A safety kernel operates with the highest level of privilege and is kept as small as possible to allow for rigorous verification. This separation ensures that even if the main application crashes or is compromised, the safety functions remain operational.
Privilege Separation
Running the kernel in a dedicated memory space prevents other software from interfering with its logic. The safety kernel evaluates requests for critical actions against a set of hardcoded safety rules. This design prevents a single programming error in the application layer from causing a catastrophic failure.
Constraint Enforcement
Monitoring the state of the physical hardware allows the logic to override unsafe commands. For instance, the safety kernel might prevent a robotic arm from moving if a human is detected in the workspace. These rules are absolute and cannot be bypassed by the higher level control software.
Verification Path
Proving the correctness of the kernel code is easier because the logic is minimal. Developers use formal methods and mathematical proofs to ensure that the safety kernel will always reach a safe state. This high level of certainty is required for systems where failure results in extreme damage or loss.
