Unformatted text preview: From a blue ribbon panel report on the V−22 Osprey problems:
"Safety [software]: ... Recommendation: Improve reliability, then verify by extensive test/fix/test in challenging environments." ! c
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Does Software Fail?
Failure: Nonperformance or inability of system or component to perform its intended function for a specified time under specified environmental conditions.
A basic abnormal occurrence, e.g., burned out bearing in a pump relay not closing properly when voltage applied Fault: Higher−order events, e.g.,
relay closes at wrong time due to improper functioning of an upstream component. All failures are faults but not all faults are failures. Reliability Engineering Approach to Safety
Reliability: The probability an item will perform its required
function in the specified manner over a given time period and under specified or assumed conditions. (Note: Most software−related accidents result from errors in specified requirements or function and deviations from assumed c...
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- Spring '09
- Safety engineering, Hazard Analysis, safety constraints