The applicability of standard MRP software packages in industry is discussed. The paper introduces four elementary types of production units, namely, the process industry shop, the mass assembly shop, low volume component manufacturing, and the project shop. The main production control issues are investigated for each of these shops, and com pared with standard MRP. It is concluded that standard MRP is only suitable for the mass assembly shop. The discussion leads to a specification of the desired developments in information systems. An important point here is the distinction between factory goods flow control and production unit control. This distinction enables the development of dedicated production unit control information systems, which may have a standard interface to factory control information systems.