We will first define a system, define an information system and, finally define an accounting information system. It should be obvious that all information systems are systems but not all systems are information systems. A vending machine, for example, is a system that is not an information system. Similarly, all accounting information systems are information systems, but the reverse is not always the case. Human resource information systems, production scheduling systems, strategic planning systems are examples of information systems that are not accounting information systems.