Architectural solutions of local numerical control systems are presented, analysis of their integration options at the system and application levels is given. Features of the latest generation of CNC systems are considered. The focus is on the modular construction of a single-computer CNC system and the principles of interaction of modules within an open architecture. All sections of NC system application software are presented. It is shown how the concepts of the subject area (interpreter, interpolator, language processor, etc.) relate to the concepts of programming (object type, attribute, operation, etc.). Functionalities of modern CNC systems are described.