Capability of a product to perform specified functions under specified conditions for a specified period of time without interruptions and failures.
Note: Wear does not occur in software. Limitations in reliability are due to results from faults in requirements, design and implementation, or from contextual changes.”
Dependability is often used as a synonym for reliability. However, dependability has a larger scope in that it includes security, performance efficiency, and continuing support and others in addition to reliability.
Extent to which a program can be expected to perform its intended function with required precision.