These input devices of a computer. The reason why these are input is they input data to the computer. The data is input to the computer using these devices.

These are output devices for a computer. These output the data put in by the input devices. The are all used like the projector for projecting things.

Touch screen is both input and output as it inputs data and outputs data. It does this by typing the screen which is putting data in and the screen/monitor which projects the image of what is going to be on the screen.

A VDU is a ‘visual display unit’ which is the British term used to describe any thing that can be seen on a screen or a computer. An OMR is ‘optical mark reader’ or an ‘optical mark readers’ which is a system that gathers information by using hardware device that detects a reflects or an absence or reflection from a card or piece of paper.