What is a Computer Monitor?

The number of pixels or picture elements on the screen determines the resolution or clarity of the picture that monitors achieve. High-resolution monitors have resolution of 2000×2000 pixels, though few present-day computers able to provide image, which take advantage of this degree of clarity. The old-fashioned IBM PC, for example, with a Color Graphic Adaptor (CGA), can only output images with a resolution of 640 pixels horizontally by 200 vertically. This was adequate for character-based displays but for graphics it was hopelessly inferior to the displays to the displays of more advanced machine such as the Apple Macintosh.

In the mid-1980s IBM introduced the Enhanced Graphics Adaptor (EGA), which offered a higher resolution. This gave a much better clarity, though it was still not as good as the Macintosh.

Then in 1987, IBM brought out Video Graphics Array (VGA) on its PS/2 range of microcomputers, with a resolution of 640×480. This was quickly taken up by the PC-compatible world and became the standard. In 1990 IBM brought out Extended Graphics Array (XGA) with resolution of 1024×786 pixel and support for 65000 colors. Super VGA with the same resolution became available from competing manufactures and this has become the standard.