Computer Monitors essays

Computer Monitors essays The most used output device on a computer is the monitor. The display provides instant feedback by showing text and graphic images. Most desktop computers use cathode ray tube displays. Portable computers use liquid crystal display (LCD). LCD monitors are now beginning to replace CRTs. This is due to a slimmer design and a use of less energy (How Stuff Works). IBM introduced the Color Graphics Adapter (CGA) in 1981. It was capable of rendering four colors. It had a maximum resolution of 320 pixels horizontally by 200 pixels vertically. In 1984 the Enhanced Graphics Adapter (EGA) was introduced. This allowed 16 different colors. Its resolution was increased to 640x350 pixels. This improved the appearance of the display (PC Tech). The Video Graphics Array (VGA) was introduced in 1987. VGA monitors are still in use today. This is a standard established to provide higher pixel addressability. The VGA consists of seven sub-systems, including: graphics controller, display memory, serializer, attribute controller, sequencer and CRT controller (PC Tech). The graphics controller can perform logical functions on data being written to display memory. Display memory is a bank of 256k DRAM divided into four 64k color planes. It is used to store screen display data (How Stuff Works). The serializer takes display data from the display mem ory and converts it to a serial bit stream which is sent to the attribute controller. The attribute controller contains the color look up table which determines what color will be displayed for a given pixel value in display memory (PC Tech). The Extended Graphics Array (XGA) came about in 1990. Its resolution in true color is 800x600 pixels, and 1024x768 in 65,536 colors (How Stuff Works). The size of your display is determined by aspect ratio and the screen size. Most displays use an aspect ratio of 4:3 (How Stuff Works). The projection surface of the display is called the screen...