Reliability is a Quality Characteristic concerning the degree to which a subject performs specified functions under specified conditions for a specified period.
Reliability can apply to:
Reliability does not mean that a subject never fails. Reliability concerns whether the subject satisfies defined expectations for operation under stated conditions for a stated period.
Reliability can concern:
Reliability can identify:
Reliability can be evaluated using measures such as:
Within the Governed Node Service Market, Reliability supports:
A Qualified Node demonstrates Reliability by performing its governed functions according to the applicable conditions, service expectations, Governance Policies, and Acceptance Criteria.
Quality Characteristic concerning the degree to which a subject performs specified functions under specified conditions for a specified period
Adapted from:
The original shared definition described Reliability as the ability of a Qualified Node to perform a governed function correctly and consistently under stated operating conditions.
This revision generalizes Reliability for use throughout the shared DIDO corpus while preserving the original Qualified Node and Governed Node Service Market application.
Reliability differs from Availability:
Availability can contribute to a Reliability evaluation, but Availability and Reliability are not interchangeable.
Reliability differs from Functional Correctness:
A subject can perform an incorrect function consistently.
A subject can produce correct results during successful operations while failing too frequently to satisfy its Reliability criteria.
Reliability differs from Operational Stability:
Reliability differs from Recoverability:
Recoverability can contribute to Reliability but does not replace Reliability.
A completed Test Run assigned a failing Verdict does not necessarily indicate a Reliability failure. The Verdict can concern Functional Correctness, Performance Efficiency, Security, Interoperability, or another Evaluation Characteristic.
A Test Execution Exception does not necessarily indicate failure of the evaluated subject. The exception can originate in:
The applicable Acceptance Criteria should distinguish:
A persistence Node records Evidence references and retention metadata during normal operating conditions and after a controlled restart.
The applicable Acceptance Criteria establish:
The Node exhibits Reliability when it performs the specified functions according to those conditions and limits throughout the evaluation period.
In a separate DIDO-TE evaluation, three Candidate Solutions perform the same function for 72 hours under a common workload. DIDO-TE records each attempted operation, successful operation, failure, period of unavailability, recovery attempt, Test Execution Exception, and supporting Evidence.
The resulting Test Results support a comparative evaluation of Candidate Solution Reliability.
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