Inputs, Processes and Outputs
Outputs
An output is a result produced by a program or system — anything it sends out so that a person or another device can use it. Every output leaves the program in some form, which is why a program that shows nothing, saves nothing and controls nothing is of little use.
Where outputs can go
An output does not have to be seen. It can be shown on screen, printed on paper, saved to a file, played as sound, or sent as a signal to a device. The choice depends on who or what needs the result: a person reading it, a record kept for later, or a machine that must act.
| Type of output | Example |
|---|---|
| Shown on screen | The final score displayed at the end of a quiz round |
| Printed | A receipt printed for a repaired bicycle |
| Saved to a file | A club's attendance list stored so it can be opened again next week |
| Played as sound | A station announcement naming the next platform |
| Sent as a signal | A robot vacuum starting its cleaning cycle at a set time |
Signals that control a device
Some outputs carry no words or pictures at all. They are short signals sent to a device, and the device responds by turning itself on or off. This is useful because the program decides when the device should work, while the device supplies the physical effort. For example, a car park barrier stays down until a ticket has been paid; the program then sends a signal that raises the arm. If the signal is never sent, the arm stays where it is.
Outputs are easy to miss
A file written quietly in the background and a signal sent to a device are just as much outputs as a score on screen, even though nobody watches them happen. Judge an output by whether it leaves the program and is used elsewhere, not by whether it appears on a display.
Practise this
OCR GCSE Computer Science · Inputs, Processes and Outputs