Setting Reliability Demands

The reliability dilemma

Reliability is expensive. Setting very high reliability thresholds might be too costly.

Reliability of critical component may be traded off with a replacement policy, assuming that component is detected in time, and the recovery time is acceptable.

Reliability analysis

Replacing a component is also costly, and it might involve interruption in the system functionality.

The costs of reliability should be compared with those due to the interruption and recovery activities.

Guidelines

Unless it is guaranteed that the operators can be trained to cope with hardware faults, the design should maximize their reliability.