Re: 1M SIMM and 4M SIMM

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#20398

From: Rogier Wolff
Date: Wed, 27 Jan 1993 17:43

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>In article <chans.727489458@marsh> chans@cs.curtin.edu.au (Sean Chan) writes:

>>possible combination is to trade 4x1 Mb SIMMs for a 4x4Mb SIMMs, and
>>leaving the remaining 4x1 Mb SIMMs, giving a total of 20 Mb. However,
>>isn't there some kind of problem with having more than 16 Mb of RAM??
>>Something to do with the DMA controller??

Nope. Not with the DMA controller. However you are right: There is something
to watch out for. Devices on the ISA bus only have access to the lower
24 address lines, for a total of 16Mb of memory. They can't access
(DMA) memory above 16Mb. Thus software using DMA on these devices should
be aware that they can't send things to above the 16Mb boundary.

						Roger.
-- 
****   a 486 in V86 mode is like a VW buggy with a 6 litre V12 motor.  ****
EMail:  wolff@duteca.et.tudelft.nl   ** Tel  +31-15-783643 or +31-15-142371

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References: <93018.221727AGCKK@ASUACAD.BITNET> <chans.727489458@marsh> <1993Jan20.150821.17135@imagen.com>

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From: wolff@liberator.et.tudelft.nl (Rogier Wolff)
Subject: Re: 1M SIMM and 4M SIMM
Message-ID: <1993Jan27.174356.18852@donau.et.tudelft.nl>
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References: <93018.221727AGCKK@ASUACAD.BITNET> <chans.727489458@marsh> <1993Jan20.150821.17135@imagen.com>
Date: Wed, 27 Jan 1993 17:43:56 GMT
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