Rudolf Kálmán (origin)Control theory, 1960
A system is observable if its internal state can be inferred from its external outputs — the mathematical root of the modern term.
Charity MajorsObservability Engineering, 2022
For software and business systems: the power to ask arbitrary new questions of your system's behaviour — via rich telemetry — without shipping new code to answer them.
The EclipseFrontiers® LensMonitoring answers known questions. Observability answers tomorrow's.