What four functions must exist in an information processing cycle and what happens in each?

The four computer functions are:

- data input

-data processing

-data storage and

-data output

The relationship between these and processing is that when data is entered into a computer,that is input, then the computer fetches it,decodes it executes it and results are stored in the CPU registers or even the user can choose to store to any other storage media.Therefore,the four functions of a computer are stages of information processing.