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From: guzzi@uiucdcsb.CS.UIUC.EDU
Newsgroups: net.micro
Subject: Re: AT&T PC6300 PLUS 1meg on motherboar
Message-ID: <4400124@uiucdcsb>
Date: Wed, 16-Oct-85 11:44:00 EDT
Article-I.D.: uiucdcsb.4400124
Posted: Wed Oct 16 11:44:00 1985
Date-Received: Sat, 19-Oct-85 05:14:46 EDT
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Nf-From: uiucdcsb.CS.UIUC.EDU!guzzi    Oct 16 10:44:00 1985


	I think that MS-DOS has a 640k limit on the amount of memory
that it will address, which may explain why the diagnostics report
only 512k.

	But, I am a bit confused.  I know that the 8086 processor in the
pc6300 has 20 address bits == 1meg, but what about the video ram?
I have a pc6300 with 640k in it.  The norton utilitites report the
following:

640k from hex paragraph 0000 to A000 (a hex paragraph is 16 bytes)
 32k from hex paragraph B800 to C000 
(some of this may be phantom memory)

I assumed that the extra 32k was the 32k of video ram.  Hex paragraph
B800 is address 736k, which is right in the middle of your 1 meg of
memory.  Is this 32k real memory?  If not, then can you really address
all 1 meg of ram using either a ram disk or another operating system,
like XENIX?  
		      --Mark Guzzi
			University of Illinois at Urbana-Champaign
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