An information system differs from other systems in the sense that its objective is to monitor/document the operations of other systems, which we can call the target systems. An information system cannot exist without such a target system. For example, production activities would be the target system of a production scheduling system, human resources in the business operations would be the target system of a human resource information system, and so on. It is important to recognize that, within a vending machine, there is a component/sub-system that can be considered an information system. In some sense, every reactive system will have a sub-system that can be considered an information system, whose objective is to monitor and control such a reactive system.