Feedback
It is sometimes good to have feedback in an ICT system. This is when the Data which is sent out of a system. from a system feeds back to influence the Data which is inserted into a system for processing and/or storage. and the process repeats itself.
A good example is a system set-up to control water temperature in a tropical fish tank. The temperature of the water is taken as an input from A device that measures a physical quantity and converts it into a signal to be read and interpreted.. Processing takes place and the temperature of the water is compared against the pre-programmed parameters, eg maximum/minimum temperature. The outputs include the automatic decision to either turn on or off the heater to warm or let the water cool. The output, ie the change in the water's temperature, is then fed back by the sensors as an input and the process repeats itself.
Feedback can occur in Data that has meaning, not just a number or a letter.-based systems as well. Often an output will have a result on further inputs. For example, the output of accepting an online booking for an air ticket will be to reduce the number of tickets available.