On-line Process Synthesizer (simulation) (OPS) A system for discrete simulation under CTSS developed by M. Greenberger at MIT ca. 1964.
[Sammet 1969, p.660. Versions: OPS-3, OPS-4. "On- line Computation and Simulation: The OPS-3 System", M. Greenberger et al, MIT Press 1965]. Last updated: 2003-04-05