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From: nate@bsd.coe.montana.edu (Nate Williams)
Newsgroups: comp.os.386bsd.questions
Subject: Re: > 16 MB of RAM
Date: 2 Jul 1993 05:15:03 GMT
Organization: Montana State University
Lines: 36
Distribution: world
Message-ID: <210g8n$3pr@pdq.coe.montana.edu>
References: <1993Jun30.184624.15579@leland.Stanford.EDU> <20ub8n$ngn@germany.eu.net> <20vaj1$8el@hrd769.brooks.af.mil>
NNTP-Posting-Host: bsd.coe.montana.edu
In article <20vaj1$8el@hrd769.brooks.af.mil> burgess@hrd769.brooks.af.mil (Dave Burgess) writes:
>>|> Is anyone running 386bsd with more than 16 MB of RAM?
>>
>>However, it does not have a SCSI interface, and I do not know whether anything
>>above 16M actually gets *used*.
>>
>
>The general feeling that I have gotten is that memory above 16M is used,
>but can cause problems if you are using an SCSI controller in an IDE
>system.
When you can't run more than 16MB of memory is when
1) You have an ISA box - limits you to 24 data lines == 16MB
2) You use a disk controller that does DMA (Direct Memory Access)
(Most decent SCSI boards use DMA to get better performance, so
that is why SCSI comes up so often. IDE drives do not, and
as such don't suffer from having more than 16MB, but also
don't have the same performance)
Theoretically, you get have the same problems if you put an ISA board that
does DMA in an EISA box, since the board is limited to 24 bit address lines.
>I personally have 32Meg of memory and a 40M swap. I am using an
>Ultrastore 24F EISA controller in IDE emulation mode. I have never had
>any serious problems that I could ascribe to having too much memory.
EISA controller == EISA box == No 24 bit address problems. :-)
Nate
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