An information system differs from other kinds of systems in that its objective is to monitor/document the operations of some other system, which we can call a target system. An information system can not exist without such a target system. For example, production activities would be the target system for 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 recognise 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 subsystem that can be considered an information system whose objective is to monitor and control such a reactive system.