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Showing posts with the label FTT

How to achieve FTT by design

For every safety critical system, FTT requirements are specified by the OEM. What we often notice is that SW teams do not know the complete picture of how these timings are fulfilled. They tend to think that if testing proves that the FTT time is met, that is sufficient. Then they start to see that even though the Safety SW or HW of the System has not changed, suddenly FTT time measurements from testing start to change noticeably. In some cases that these measurements exceed the required FTT, and now suddenly the team is left wondering how this happened. " We did not change the Safety SW. Looks like the Non-safety part of the system is causing this change but we do not have control over it " they say. If you look at it from the ISO26262 Part-6 V model perspective, on the left side of the V is the Architecture design and the right side of the V is the Verification and Testing.  The argument of proving that FTT was met via testing is in the right side of the V. However, what we