The control computer named ETL-RTC aimed at studying computer control is described. Several questions regarding «computer control are discussed, and the hybrid type computing system is recommended as the most suitable one from nowadays engineering standpoint. The features and details of RTC are also mentioned. Two examples of this computer application are described. One is the measurement of process parameters to adapt controllers to environmental changes and the other is the solution of two-point boundary value problems of Euler's equation to get the maximum efficiency of the process.