Determinism means that under the same inputs and initial conditions, a system produces the same externally observable behavior. This is foundational for reproducible testing, debugging, formal reasoning, and fault-tolerant replication.

Determinism Levels

  • Functional determinism: same inputs and state lead to the same outputs.
  • Temporal determinism: responses are produced within specified time bounds.
  • Sequential determinism: relevant event ordering is consistent and well-defined.

Notes For AI-Enabled Systems

Determinism can be engineered at system level even when model internals are probabilistic, for example by controlling prompts, tool orchestration, model/version pinning, and runtime configuration.

References

  1. Fred B. Schneider, “Implementing Fault-Tolerant Services Using the State Machine Approach: A Tutorial”, ACM Computing Surveys 22(4), 1990. https://dl.acm.org/doi/10.1145/98163.98167
  2. Leslie Lamport, “Time, Clocks, and the Ordering of Events in a Distributed System”, Communications of the ACM 21(7), 1978. https://dl.acm.org/doi/10.1145/359545.359563
  3. C. L. Liu and James W. Layland, “Scheduling Algorithms for Multiprogramming in a Hard-Real-Time Environment”, Journal of the ACM 20(1), 1973. https://dl.acm.org/doi/10.1145/321738.321743