In safety engineering
, the term fail safe
has the following meanings:
1. Of a device, the capability to fail without detriment to other devices or danger to personnel.
2. Pertaining to the automatic protection of programs and/or processing systems to maintain safety when a hardware or software failure is detected in a system.
3. Pertaining to the structuring of a system such that either it cannot fail to accomplish its assigned mission regardless of environmental factors or that the probability of such failure is extremely low.
The term fail-safe operation has the following meanings:
1. Operation that ensures that a failure of equipment, process, or system does not propagate beyond the immediate environs of the failing entity.
2. A control operation or function that prevents improper system functioning or catastrophic degradation in the event of circuit malfunction or operator error.
Sources: from Federal Standard 1037C and from the National Information Systems Security Glossary in support of MIL-STD-188
" or "Fail Safe" is also the title of a novel, movie, and made-for-television play
about a possible accidental nuclear war