The Input-Process-Output (IPO) Model, also known as the IPO+S Model, is a functional model and conceptual schema of a general system. The components of the IPO model are defined as: I: Input – The information, ideas, and resources used in creating a program P: Processing – Actions taken upon/using input or stored material O: Output – Results of the processing that then exit the system S: Storage – Location(s) where material inside the system is/are placed for possible use at a later point in time