<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]. (2003-04-05)