Visual output devices

output device display information from the computer to the user. the main output devices display data on a screen print data on paper, and play data as sound.
With modern software the screen display is the most important interface the user has with a computer. All commands are issued using a mouse or keyboard to select elements of a graphical user interface such as menues and toolbar.

Displaying data on screen requires two components.

• The graphic card is often connected to an expansion slot (PCI or AGP) on the motherboard. Many graphic cards are optimised to display 3D graphics effects. They often incorporated sophisticated. microprocessor and have thrir memory so that the screen display can be kept updated as smoothly as possible.
• The visual display unit displays an image on a screeen recording to the data supplied to it by the graphic card.

These componnents need to be compatible in order to work together. Almost all modern display system use the SVGA standerd. SVGA support high colour depth resolution and refresh rate. Older display standerd include VGA and XGA which are not compatible of such high performance.