Source: http://en.wikipedia.org/wiki/Software_System_Safety
In Software Engineering, Software System Safety optimizes system safety in the design, development, use, and maintenance of software systems and their integration with safety critical hardware systems in an operational environment.
Software System Safety engineering must be given emphasis early in the requirements definition and conceptual design process
Safety-critical software must receive continuous management emphasis
safety-critical functionality should be identified before deriving hazards and design safeguards for mitigations.
Safety-Critical functions lists and preliminary hazards lists should be determined proactively
Safety-Critical functions lists and preliminary hazards lists should influence the requirements that will be implemented
Reliance on administrative procedures for hazard control is minimized.
The number and complexity of safety critical interfaces is minimized.
The number and complexity of safety critical computer software components is minimized.
Failure modes, including hardware, software, human and system are addressed in the design of the software.
Safety issues are addressed as part of the software testing effort at all levels of testing.