ITPEC IP April 2018 Question 51
Availability, performance, data consistency, maintainability, and such other indicators are used to represent the capabilities and quality of a system. Which of the following is an appropriate description of availability?
Explanation
The degree to which functions can be used, even when a failure occurs — availability is how much of the time the system can actually be used.
Availability is the proportion of time the system is running and usable, commonly MTBF ÷ (MTBF + MTTR). It rises when failures are rare and short: redundant components keep functions running through a failure, and quick recovery shortens the downtime.
Answer (c)
Why not others:
- •(a) — keeping associated data consistent is data consistency (integrity)
- •(b) — the time from giving an instruction to getting the result is response time, a measure of performance
- •(d) — how easily programs can be changed is maintainability
Key rule: The RASIS indicators: Reliability (few failures, MTBF), Availability (usable when needed), Serviceability (quick repair, MTTR), Integrity (consistent data) and Security (protection from unauthorized use).
System Component · AI-written, may contain errors
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