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From: michaelv@iastate.edu (Michael L. VanLoon)
Newsgroups: comp.os.386bsd.questions
Subject: Re: panic during extract
Date: 3 May 94 07:11:56 GMT
Organization: Iowa State University, Ames, Iowa
Lines: 36
Message-ID: <michaelv.767949116@ponderous.cc.iastate.edu>
References: <2psi93$anl@news.service.uci.edu> <2q3b1n$men@pdq.coe.montana.edu>
NNTP-Posting-Host: ponderous.cc.iastate.edu
Keywords: page fault kernel panic
In <2q3b1n$men@pdq.coe.montana.edu> nate@bsd.coe.montana.edu (Nate Williams) writes:
>Also, if the chip is the Cyrix chip then it could be problem as well as
>I don't think FreeBSD correctly handles it as it is not 100% Intel
>compatible.
The Cyrix SLC/DLC *is* 100% *software* compatible with the Intel 486
(with a few extra registers added). It is *not* 100% Intel *hardware*
compatible, since it has internal caching. You have to be careful
about how caching is enabled since there are no hardware cache
management lines on a 386-class chip (like there are on the Intel
486). The SLC/DLC is hardware "compatible" with the 386-class
processors, so you have to be careful how you enable caching options.
I have been running a Cyrix 486DLC in a 386 caching motherboard for
several weeks now with excellent results. I have modified locore.s,
machdep.c and cputypes.h to correctly identify the Cyrix part and
enable certain caching options. Then, I modified dma.c and the scsi
driver (bt742a.c) to maintain cache coherency by invalidating the
internal processor cache at strategic points.
I have beat the machine extensively in this configuration, and am
getting quite satisfying results.
If you have a BIOS, however, that enables fast&loose caching options
on your Cyrix processor and just hands it off to the NetBSD/FreeBSD
booter that way, without any detection of specific Cyrix parts in a
386-class, non-Cyrix-aware motherboard, you are probably going to wind
up with problems.
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Michael L. VanLoon Iowa State University Computation Center
michaelv@iastate.edu Project Vincent Systems Staff
Free your mind and your machine -- NetBSD free Un*x for PC/Mac/Amiga/etc.
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