Positioned between CGA and VGA in terms of its characteristics (color and spatial resolution). Released by IBM in 1984 for a new model of the IBM PC AT personal computer. The EGA video adapter allows using 16 colors at a resolution of 640×350 pixels. The video adapter is equipped with 16 kB of ROM to expand the graphics functions of the BIOS.
The EGA adapter at a resolution of 640*350 allows you to simultaneously use 16 colors out of a possible 64 (two bits for red, green and blue components). EGA also supports 16-color variants of CGA 640*200 and 320*200 graphics modes; in this case, only colors from the CGA palette can be used. Native CGA modes are also supported, although EGA is not fully hardware compatible with CGA. EGA can display an image on an MDA monitor, this feature is enabled using the switches on the board, while only 640 * 350 mode is available. The EGA board is connected to the ISA bus starting from the 8-bit version. The basic version of EGA had 64 kB of video memory, which was enough for high-resolution monochrome graphics and color graphics in 640*200 and 320*200 modes. Over time, most EGA boards began to be produced with 256 kB of video memory. Some third party EGA clones (notably ATI Technologies and Paradise) support advanced graphics modes (eg 640*400, 640*480 and 720*540), automatic monitor type detection and sometimes a special interlaced mode for CGA monitors. The EGA standard was superseded by the VGA standard introduced by IBM in April 1987 with the PS/2 computer model.Add a comment