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Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!iuvax!rutgers!cmcl2!rna!marc
From: marc@rna.UUCP (Marc Johnson)
Newsgroups: comp.sys.atari.st,comp.sys.apple,comp.sys.mac,comp.sys.ibm.pc
Subject: Re: VGA, EGA, CGA: what is the difference?
Message-ID: <380@rna.UUCP>
Date: 24 Feb 89 05:56:15 GMT
References: <4306@psuvax1.cs.psu.edu>
Reply-To: marc@rna.UUCP (Marc Johnson)
Organization: Rockefeller University Neurobiology
Lines: 55

In article <4306@psuvax1.cs.psu.edu> deng@shire (Mingqi Deng) writes:
>Can any netter tell me what differecnce VGA, EGA and CGA make and what
>'campatible to VGA and EGA' implies?
>
>Thanks in advance.
>
>Mingqi

CGA, EGA and VGA all stand for IBM's video interface standards, and each
corresponds to an adapter card that IBM provided with various systems.  The
main difference between them is in resolution of the image and the number of
colors available.

CGA (Color Graphics Adapter) was first available with early PC systems,
and provides 16 colors and 640 lines X 200 lines of resolution.  Most
graphics- and color-oriented software written until recent years was
written for this standard.  Its character rendition is generally considered to
be poor for text-intensive applications.

EGA (Enhanced Graphics Adapter) has gained popularity more recently, due to
its superior character rendition in either 25- or 43-line modes, and greater
graphics resolution (up to 640 X 350).  EGA can also display 16 simultaneous
colors, but these 16 are drawn from a palette of 64.  EGA requires a monitor
capable of handling the higher resolution is required for an EGA adapter card.
EGA cards are generally fully CGA-compatible.  Most business software and other
recent software (including MicroSoft Windows) requires EGA.

VGA is the latest and greatest.  It was introduced by IBM with its PS/2 line.
It supports up to 640 X 480 resolution, and 16 colors frmo a palette of
256,000 (!) colors.  Actually, one VGA mode supports lower resolution
(320 X 200) with 256 simultaneous colors.  The popular MultiSync or
MultiScanning monitors you may have seen around are able to handle
higher-than-EGA resolutions, and in some cases, VGA.  Because of the higher
clock rates and bandwidth required for VGA, VGA-compatible monitors use
analog display technology instead of the TTL (digital) technology used before.
The MultiSync monitors have two input connectors and can handle the two
different output modes, depending on the adapter card to which they're
connected.


It sounds like you're shopping either for a card or a monitor, so I suggest
you take peek at BYTE February and March '88.


-Marc

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