Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cs.utexas.edu!uunet!sdrc!scjones
From: scjones@sdrc.UUCP (Larry Jones)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Why no graphics in text mode?
Message-ID: <1036@sdrc.UUCP>
Date: 12 Jan 90 22:46:35 GMT
References: <25820@cup.portal.com>
Organization: SDRC, Cincinnati
Lines: 24

In article <25820@cup.portal.com>, cliffhanger@cup.portal.com (Cliff C Heyer) writes:
> I'm trying to figure out why there is this division 
> between text and graphics modes with PCs. 
> [...]
> I'm assuming that each screen pixel is represented 
> by a bit in memory (or several bits) even in text 
> mode - but in text mode the bits are written with 
> bit maps from the BIOS.

Bad assumption.  In fact, this is exactly what happens in GRAPHIC
modes -- whenever you make a BIOS call to write characters, the
BIOS discovers that you're in a graphic mode and writes the
appropriate bit maps into the display memory.

In TEXT modes, however, the display memory actually contains the
ASCII characters to be displayed and the video HARDWARE converts
them into bits on the fly.
----
Larry Jones                         UUCP: uunet!sdrc!scjones
SDRC                                      scjones@SDRC.UU.NET
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