Requirement completeness: Requirements are sufficient to distinguish the desired behavior of the software from that of any other undesired program that might be designed. .
What [software] must not do is not the inverse of what it must do. .
Software−related accidents are usually caused by flawed requirements.
Safety is an emergent property of systems, not a component property.
Highly reliable components are not necessarily safe. .
Reliability engineers often assume that reliability and safety are synonymous, but this assumption is true only in special cases.