A modeling and control process for distributed factories having fabrication sequences starts with a definition of how the factory actually operates, rather than a mathematical theory which ultimately leads to a definition of the plant operation. The process begins by delineating a set of factory operating rules which define how part lots interact with machines in actual operation of the factory. A dynamic model of the factory is selected from a group of specimen models for such factories. The model defines the factory by its machines, products, fabrication sequences, collections of job sets, scheduling rules, and machine reliability parameters. The parameters that describe the specific factory are determined and defined in terms of data structures of the individual factory model. The factory specific model contains descriptions of the dynamic interactions of lots and machines. The behavior of the factory can be simulated in detail. A comparision of such a simulation against actual observation of the factory can be used to refine the model. Because the process begins with a definition of how the factory actually operates, calculations for even very complex-factory simulations, such as integrated circuit fabrication facilities, are simplified so that small computers, such as personal computers, may be employed. The models and simulations can be made accurate enough to allow automatic computer control of the factory using the models and simulations.