Maintainability is how quickly, easily and cost effectively a system can be returned to operational status after maintenance is performed. It is measured by ______________.

Maintainability is how quickly, easily and cost effectively a system can be returned to operational status after maintenance is performed. It is measured by ______________.

• A. Availability
• B. Mean Time To Repair (MTTR)
• C. Reliability
• D. Downtime

Answer: (B)

Maintainability is about how quickly and easily a system can be returned to operation after a failure. The metric that directly measures that speed of repair is the Mean Time To Repair, which averages the total time needed to diagnose, fix, and restore service after a fault. Availability is a broader performance measure—the fraction of time the system is up, influenced by both how often failures occur (failure rate) and how long repairs take. Reliability focuses on how likely the system is to operate without failure over a period of time. Downtime is the actual period when the system is not operational, an outcome rather than a measure of how repair-friendly the system is. Reducing the repair time directly improves maintainability, which is why Mean Time To Repair is the best fit.

Maintainability is about how quickly and easily a system can be returned to operation after a failure. The metric that directly measures that speed of repair is the Mean Time To Repair, which averages the total time needed to diagnose, fix, and restore service after a fault.

Availability is a broader performance measure—the fraction of time the system is up, influenced by both how often failures occur (failure rate) and how long repairs take. Reliability focuses on how likely the system is to operate without failure over a period of time. Downtime is the actual period when the system is not operational, an outcome rather than a measure of how repair-friendly the system is. Reducing the repair time directly improves maintainability, which is why Mean Time To Repair is the best fit.