TOPAS: A system of programs to size and evaluate mini-computers for real-time applications

The TOPAS (Tom's Omni-Purpose Assembly and Simulator) system consists of a set of programs which provide a simulation environment to study the use of a mini-computer for a real-time application. TOPAS operates on a large, general purpose computer in a time-sharing mode of operation and provides the actual coding and simulated execution of a realistic prototype of the application, thus demonstrating feasibility and verifying the computations and algorithms used. Extensive run-time statistics are generated to show timing and space considerations and to assist in sizing candidate real machines. TOPAS includes the simulation of a generalized mini-computer whose machine architecture and assembly language are characteristic of most real machines. It also includes an assembler and a simulator to execute the assembled programs. FORTRAN routines simulate the real world as seen by the minicomputer.

The TOPAS system was developed during a study concerning the feasibility of using a minicomputer in the control loop of an existing electromechanical system. The object of the study was to demonstrate the feasibility of a general purpose, sequential digital computer as against a custom-built, hardwired, parallel sequencer, and to determine the speed and storage requirements of the digital computer.