Graceful degradation

What type of graceful degradation of product performance is desired when portions of the product fail This would determine the type of power busing scheme and power sequencing that may be necessary within the system. 

Any graceful degradation features and repair philosophy after system failure. 

Graceful degradation Each business function is supported by its own machinery, so one malfunction doesn t stop the whole enterprise. 

The LINUX cluster had been managed under continually increasing load for a period of months. Systems administrators had responded by incremental addition of PCs, but the performance had shown continued decline. The system was loaded near capacity, which is often far below theoretical, 70% of maximum being a common benchmark. Another feature of the system, which is especially relevant to clusters, was the impact of component failure. For computers, this is likely the disk drive. Drives have a mean time between failure of one to two years and follow a bathtub curve of burn-in failure, followed by reliable performance and then high failure near the end of the lifecycle. Cluster design must take into account the need for graceful degradation. 

For operators to anticipate or detect hazardous states, they need to be continuously updated about the process state so that the system progress and dynamic state can be monitored. Because of the poor ability of humans to perform monitoring over extended periods of time, they will need to be involved in the task in some way, as discussed earlier. If possible, the system should be designed to fail obviously or to make graceful degradation obvious to the supervisor. 

Graceful degradation An equipment failure mode in which the system suffers reduced capability, but does not fail altogether. 

High availability. Clusters provide multiple redundant identical resources that, if managed correctly, can provide continued system operation through graceful degradation even as individual components fail. 

Environmental change and competition are two major challenges that all biological systems must cope with. Adaptability to changing external conditions, or robustness, of a system typically manifests itself in terms of a parameter insensitivity of its dynamics and a graceful degradation of its components. Competition, on the other hand, drives a system towards optimality, as a less efficient system will find itself at an evolutionary disadvantage. 

Robustness Graceful degradation. Natural light harvesting systems are tolerant to the loss of individual components. Loss of one pigment generally does not prove detrimental beyond the loss of the corresponding cross-section. 

Recovery mechanisms or graceful degradation (mostly for hardware faults)... 

The very light sensitive rods are excluded from color interpolation Their neuronal signals are overlaid as monochromatic (not as color opponency) into the information feed to the optical nerve (see Sect. 3.1). From this it can be deducted why human vision fades from photopic (day light) over mesopic (twilight) to scotopic vision (low light) with a gracefully degradation from color to monochromatic vision and an increase in sensitivity [2, p. 216]. 

Graceful degradation is a reduction of performance as a result of failure, while maintaining essential function(s) and performance. It is the capability of continuing to operate with lesser capabilities in the face of faults or failures, or when the number or size of tasks to be done exceeds the capabihty to complete. 

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