Deterministic system (noun)
A system whose rules produce the same output whenever it receives the same inputs under the same operating conditions.
Deterministic systems follow rules that determine what happens. Start with the same state, feed in the same inputs, and the system applies the same rules, resulting in the same result every time.
A calculator is the simplest example.
Enter 10 × 5 and you get 50, every time.
Software permissions work the same way. If access depends on a user's role, subscription level, and security settings, the system reaches the same decision whenever those values match.
Same inputs covers more than what our users type in. It includes things like account settings, stored data, software version, current time, feature flags, and information pulled from connected services. Change any one of those inputs, and our result can change too.
