Parallel processing strategies in the application of microcomputers to the behavioral laboratory

The Operant Package for the Neurosciences (OPN) is a software system that runs on the TRS-80 Model I and Model III and the Apple II+ and Apple lie microcomputers. It is designed to allow a single microcomputer to control behavioral experiments in up to eight different stations, record experimental data, and provide detailed data analysis. Although segments of the program are written in BASIC, allowing users to interact with OPN in a simple English question-and-answer format, the part that provides real-time experimental control is written in Z-80 assembly language. The present report describes in detail assembly language algorithms that we found to facilitate speed of processing and flexibility of control. Particular problems dealt with how to update and change flag variables controlling the reinforcement contingencies and output conditions in each station, as well as how to decide when each station should shift contingencies. The solutions to these problems utilize byte-oriented parallel processing strategies, converting serially organized reference information for each station into a group of working flag bytes that control contingency and output variables for all stations in parallel.