*BSD News Article 18006


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Newsgroups: comp.os.386bsd.questions
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From: volker@sfb256.iam.uni-bonn.de ( Volker A. Brandt )
Subject: Re: > 16 MB of RAM (on an ISA box)
Sender: usenet@work1.rhrz.uni-bonn.de (Usenet-Admin)
Message-ID: <Jul06.111906.6442@work1.rhrz.uni-bonn.de>
Date: 06 Jul 1993 13:11:26 MET
References: <210g8n$3pr@pdq.coe.montana.edu> <1993Jul2.164901.22217@leland.stanford.edu> <2121b9$73v@pdq.coe.montana.edu>
Organization: Applied Math, University of Bonn, Germany
Lines: 34

In article <2121b9$73v@pdq.coe.montana.edu> nate@bsd.coe.montana.edu (Nate Williams) writes:
>>It looks like the kernel (i386/isa/isa.c) checks that the DMA transfer
>>will be into the lower 16 MB, and if it won't, the transfer is handled
>>it in a special way (but I wasn't sure that this special handling is
>>completely implemented; it seems that it is).  So, this should not be
>>a problem.
>
>As you noted above, this special handling is not completely implemented.
>Rumor has it is has been finished in 0.2, but I don't have 0.2, and
>haven't seen anything that looks remotely like 0.2.
[...]
>>Only if the driver/OS is stupid enough to try to get the ISA board to
>>do a transfer above 16 MB.  The earlier versions of SVR4 for the 386
>>failed to check that the transfer was in the ISA range.  It looks like
>>the Bill and Lynne are smarter than USL.
>
>Unfortunately, they didn't finish the job.

So why can't we do it?  Is anyone working on this?  I have the sources and
the BSD book but I have neither the knowledge nor the time to do it.

I am, however, more than willing to help if I can, and I am also willing to 
do testing.

Anyone out there who has thought about it?  Alternatively, does anyone know
more about the way 0.2 is supposed to fix this?


Thanks -- Volker
-- 
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Bitnet:   UNM409@DBNRHRZ1                              Volker A. Brandt
Internet: volker@sfb256.iam.uni-bonn.de                Angewandte Mathematik
Phone:    +49 228 73 3427                              (Bonn, Germany)