Thursday, April 11, 2013

As the computer display works

  A few years ago color monitors for computers were considered suitable rather for games, than for serious work. The majority of programs was focused on work with the text, and on color displays this text turned out rough and difficult for reading. The first monitors with the color graphic adapter (Color Graphics Adapter - CGA) for the computers equipped with DOS system, could display only 4 colors from possible 16 and even at the highest resolution instead of smooth curves and straight lines the line on the screen one zigzags turned out.

  So far everything changed. In the world of computers now it is considered that color not only is admissible for serious calculations, but even is obligatory, especially in such Wednesdays focused on graphics, as Windows and OS-2. In modern programs color images are used not so much for advertizing, how many for transfer of large volumes of information.

  Now color displays are born a faint resemblance only with that were issued 30 years ago — with rough shades of color and limited graphic opportunities. Now instead of initial four flowers the palette from 256 flowers (for VGA monitors) is usually used, and some displays reproduce thousands shades of color. On change to the CGA adapter with the resolution of 200 lines at 640 points, good only for rough outline images, the modern displays easily providing permission of 768 lines in height and 1024 points of pixel in width came. (The pixel is the smallest logical unit which is used for creation of the image on the screen; usually it turns out from several light points adjoining to each other. The less points of light are used for receiving pixel, the resolution of the monitor is higher.)
  The success of the best modern displays consists in a combination of the perfect VGA adapter (triable Graphic Array) and high-quality monitors which can work with a set of signals from the display adapter. Old adapters used exclusively digital information; it means that each pixel of the display either was shone, or isn't present, and such way of representation complicated receiving subtle shades of color. The VGA adapter uses an analog signal, i.e. will transform digital information to the various levels of tension changing brightness of pixel. Such system demands less memory and is more universal. In Super VGA systems the increase in number of flowers and improvement of permission is provided with a special set of chips and the increased memory size.

 VGA adapters of this or that type as early as will remain many years the standard for graphic systems. Here we will consider two types of color VGA displays — the desktop monitor and the liquid crystal screen for portable personal computers.

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