What are the common time indicators for measuring the reliability of a system? (Multiple choice)

System reliability is quantified using several time-based metrics. Mean Time Between Failures (MTBF) is a primary indicator for repairable systems, representing the average operational time between failures. Average failure time, also known as Mean Time To Failure (MTTF), is a key indicator for non-repairable components, measuring the average lifespan until failure. Both are fundamental time-based indicators used to measure system reliability and are explicitly covered in storage technology principles.

A. Reliability is the overall quality or probability being measured, not a specific time indicator itself.
B. "Effective" is a general adjective and not a standard, quantifiable time-based metric for system reliability.

1. Huawei HCIA-Storage V5.0 Training Material. In the "Overview of Storage System Reliability Technologies" chapter, the section on "Reliability Indicators" defines MTBF (Mean Time Between Failures) and MTTF (Mean Time To Failure) as key metrics. "Average failure time" is the direct definition of MTTF. These are presented as the standard time-based measures for system and component reliability.

2. O'Connor, P., & Kleyner, A. (2012). Practical Reliability Engineering (5th ed.). Wiley. In Chapter 2, "Reliability Mathematics," the concepts of Mean Time To Failure (MTTF) and Mean Time Between Failures (MTBF) are introduced as fundamental time-based measures of reliability (pp. 15-17). MTTF is explicitly defined as the average time to failure.