Enhanced Graphics Adaptor
| Release date | October 1984 |
|---|---|
| Architecture | Motorola 6845, Chips and Technologies |
| Cards | |
| Entry-level | IBM EGA card, Chips and Technologies, ATI EGA Wonder |
| Mid-range | ATI EGA Wonder 800 |
| High-end | ATI EGA Wonder 800+ |
| History | |
| Predecessor | Monochrome Display Adapter, Color Graphics Adapter |
| Successor | Video Graphics Array |
The Enhanced Graphics Adapter (EGA) is a historical IBM PC computer display standard from 1984 that superseded and exceeded the capabilities of the CGA standard introduced with the original IBM PC, and was itself superseded by the VGA standard in 1987.
EGA was introduced in October 1984 by IBM, shortly after (but not exclusively for) its new PC/AT.
The EGA standard was made obsolete by the introduction in 1987 of MCGA and VGA with the PS/2 computer line.
Shortly before the introduction of VGA, Genoa Systems introduced a half-size graphics card built around a proprietary chip set, which they called Super EGA (later cards supporting an extended version of the VGA were similarly named Super VGA).
EGA produces a display of sixteen simultaneous colors from a palette of sixty-four, at a resolution of up to 640×350 pixels. The EGA card includes a 16 KB ROM to extend the system BIOS for additional graphics functions, and includes a custom CRT controller (CRTC) that has limited backward compatibility with the Motorola MC6845 chip used to generate video timing signals in earlier IBM PC graphics controllers. The EGA CRTC can support all of the modes of the IBM MDA and CGA adapters, partially through specific mode options intended for this purpose, but even in its maximum-compatibility mode configuration it is not register-compatible with an MC6845, so programs that directly program the 6845 to set up video modes will fail on an EGA. When an MDA or CGA mode is set up on the EGA by calling the BIOS, then the raster timing, video memory layout, data format, and some other low-level hardware details such as cursor control are identical to those aspects of the operation of an MDA or CGA, providing a high degree of direct software and hardware (e.g. CRT monitor) compatibility.
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