Reliability & Availability

Reliability Definitions

1. The duration or probability of failure-free performance under stated conditions.
2. The probability that a sub-system can perform its intended function for a specified interval under stated conditions.

Availability Definition

• The proportion of time the system will be operational or capable of fulfilling a stated function to the satisfaction of the user. Availability is usually expressed as a percentage or decimal fraction (0 ≤ n ≤ 1).