What is the term for the operational availability of a system, often stated as a percentage?

The term that explains the operational availability of a system, often expressed as a percentage, is availability. This concept measures the proportion of time a system is operational and accessible for use compared to the total time it is expected to be available. Availability takes into account both uptime and downtime, reflecting how effectively a system can perform its intended functions when required.

In contrast, reliability refers to the consistency of a system's performance over time, indicating how likely it is to function without failure during a specified period. Performance, on the other hand, encompasses the overall efficiency and speed of a system in executing its tasks. Normativity relates to standards and norms rather than operational metrics. Therefore, availability is the most appropriate term for describing the operational readiness of a system as a percentage.