Function of the system unit components and how they communicate

The system component is the input devices, output devices, memory unit and central processing unit. The input devices enable data to be supplied to the computer. The output devices enable output of data from computer. The memory unit stores the data and the programs which the computer uses each time. The central processing unit is made of two parts the control unit and the arithmetic logic unit.

The input devices are:
• Keyboard – allows user to input data
• Mouse – pointing device which allows user to select icons or files
• Joystick - device used for video games and for some graphics applications
• Scanner - A device that takes a picture of an image, breaks it down into dots and records it as a digital file for use with a computer
• Microphone - An audio device that converts sound energy (such as voice waves) into electrical energy which can then be amplified

The output devices are:
• Display screen – VDU (visual display unit) – it allows you to see the data that you have entered on the screen
• Printer: laser printer, ink-jet printer – it allows you to print out a paper copy of the data on your computer
• Plotter - A plotter draws images as a series of point-to-point lines

Central processing unit (CPU)
• Control unit - that directs sequence of operations, interprets coded instructions, and initiates proper commands
• Arithmetic Logic unit - performs all arithmetic computations, such as addition and multiplication, and all comparison operations