VGA, or otherwise known as Video Graphics Array, is a standardised resolution for computer monitors and projectors and allows for resolutions of a certain value of pixels to be displayed on screen. It was developed by IBM and supersedes the original EGA (Enhanced Graphics Display) which was also developed by IBM but only supported resolutions up to 640 x 350 pixels. VGA has several different types, each with its own maximum resolution display. What’s the difference? A higher resolution display can hold more pixels on a screen; therefore, there is more information that can be displayed. This usually results in neater and better looking graphics.
There are seven sub systems of VGA. These are separated into specific categories, including graphics controllers, display memory, serialiser, attribute controller, sequencer and the CRT controller. Each of these parts performs a different task and as a result, displays text and graphics on the screen. The CPU processor of a machine will process all the necessary information, and then feed it to the VGA which will then process it. The VGA system in itself is quite outdated, although standard PC’s do boot up in VGA mode, with the maximum resolution size of 640 x 480 and 16 colours.
Since VGA is much too outdated to be used in common systems such as laptops and PC’s, it has evolved into something much more complex – the XGA. This is the first step up that IBM developed that resembles something closer to what we would expect of home computers and laptop resolutions, allowing 800 x 600 pixels of high colour (16 bits per pixel) and 1024 x 768, the standard resolution that most computers run on nowadays with a palette of 256 colours. Electronic equipment such as projectors and digital cameras also use XGA support. XGA is much more aesthetically pleasing, due to the larger amount of pixels that it can hold.
Another variety of the VGA cable that we have includes the SVGA, or otherwise known as the Super Virtual Graphics Array, which was originally released as an extension to the original VGA set by IBM in 1987. SVGA was formed as a means of standardizing for cross-compatible graphics display and display adapters. While we may think of SVGA as an enhanced, better product in comparison to the XGA display, it in itself does not have a specific resolution definition and is more so a means of generalizing a higher level of graphics display featuring resolutions of 1024 x 768, and versions of SVGA which could support up to 32-bit colour.
VGA has and still is the basic fundamental of graphics display for digital devices. Although it has now been replaced by the more commonly used XGA and SVGA standards, VGA still exists as an important graphics base that will continue to guide how graphics display and resolution will operate. The VGA system has since revolutionized the display of graphics and digital equipment that still exists today, especially with low resolution technology.
Source by Robert Deans