ITPEC FE Morning April 2020 Question 15
The life cycle of a computer system can be classified from the viewpoint of failure into the three periods of early failure period, random failure period, and wear-out failure period. Which of the following is the most appropriate description of the measures in the early failure period?
Explanation
Strengthen design review and failure analysis — early failures come from design and manufacturing defects, so they are removed at the source.
The failure rate over a system's life follows the bathtub curve:
- •Early failure period: the rate is high and falling as defects left in design or manufacture surface; countered by design review, failure analysis and burn-in before release
- •Random failure period: the rate is low and roughly constant, with failures occurring by chance
- •Wear-out failure period: the rate rises as parts age; countered by preventive maintenance and replacing parts before they wear out
Answer (d)
Why not others:
- •(a) — replacing components in advance anticipates wear, a wear-out period measure
- •(b) — scheduled and condition-based maintenance detect deterioration in a system in service; they do not remove defects built in during design or manufacture
- •(c) — maintenance timed by cumulative operating time assumes failures grow with age, which is the wear-out period
Key rule: Match the measure to the cause: defects call for better design and manufacturing, ageing calls for preventive replacement, and chance failures call for redundancy and quick repair.
System Component · AI-written, may contain errors
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