IBM EGA

IBM EGA

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Enhanced Graphics Adapter was IBM's successor to CGA, introduced in 1984 with the IBM PC/AT (model 5170), though it was also available for the earlier PC and PC/XT models. A new type of monitor was introduced alongside it, the Enhanced Color Display (model 5154), though previous MDA and CGA-compatible monitors can still be used by configuring a few switches on the card itself so it outputs a compatible signal. It was designed to be backwards compatible with CGA, thus supporting all its graphics modes, and introducing several news ones, depending on the monitor it was used with. Windows 1.0 also supported such configurations with the appropriate drivers.

A monochrome EGA driver was first included with the Alpha release. The Beta added support for color modes. Emulators generally support the high-resolution 16 color EGA mode, and may support the lesser known modes as well.


With an MDA monitor

If you configure the switches on an EGA card (or emulator settings) to output a signal compatible with an MDA monitor (e.g. IBM model 5151), you only get a 640x350 monochrome graphics mode. Windows 1.0 supports this mode with the EGAMONO.DRV driver. In setup, this option is called "Enhanced Graphics Adapter (EGA) with Monochrome Personal Computer Display".


With a CGA monitor

If an EGA card is configured to output a signal compatible with a CGA monitor (e.g. IBM model 5153), you get the two standard CGA modes (see the IBM CGA page), as well as two additional modes. These are 320x200 in 16 colors, and 640x200 in 16 colors. The latter is used by Windows 1.0's EGALORES.DRV driver, which you can use if you select the "EGA with Enhanced Color Display or Personal Computer Color Display" option during setup.


With an EGA monitor

This is the most "natural" configuration for an EGA card that makes the most use of its capabilities when connected to an EGA-compatible monitor (e.g. IBM model 5154). This way you get all the modes I mentioned above in the CGA monitor configuration, as well as an additional high-resolution color mode of 640x350 pixels. The number of available colors depends on how much memory is installed on the card. On cards with 64 kB of memory, only 4 colors are available. Cards with more than 64 kB of memory can display all 16 colors. Windows 1.0 has separate drivers for these modes: EGAHIBW.DRV is the 640x350 4 color mode, designated as "EGA with Enhanced Color Display (Black and White only)" during setup, though it only uses the black and white colors as the name suggests. EGAHIRES.DRV supports the 640x350 16 color mode and is called "EGA (more than 64K) with Enhanced Color Display" in setup.