Date: Mon, 11 Mar 1996 13:25:42 -0800 (PST) From: "Rodney W. Grimes" <rgrimes@GndRsh.aac.dev.com> To: jgreco@brasil.moneng.mei.com (Joe Greco) Cc: jehamby@lightside.com, current@FreeBSD.ORG, jkh@time.cdrom.com, toor@dyson.iquest.net Subject: Re: AMD doesn't like SNAP! (panic: unwire: page not in pmap) Message-ID: <199603112125.NAA12878@GndRsh.aac.dev.com> In-Reply-To: <199603111630.KAA17767@brasil.moneng.mei.com> from "Joe Greco" at Mar 11, 96 10:30:39 am
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>
> > > So far three people, including myself, have reported the above panic
> > > message when booting the 3/3 SNAP kernel. All three of us have AMD DX4
> > > processors (100 and 120MHz). This has got to be the problem! John,
> > > Jordan, people working on the VM system, take note.. Thanks!
> >
> > Can all three of you tell me if you have A80486DX4-100NV8T's or
> > A80486DX4-100SV8B's? The difference is the SV8B is the write back
> > enhanced DX4 and unless you have a motherboard that understands
> > how to deal with this you are going to have a cache coherency problem
> > between the internal and external cache.
> >
> > I have yet to see a MB deal with this correctly when faced with
> > a bus master SCSI controller, though I have seen some that work fine
> > as long as no bus mastering is occuring. Far more don't work than
> > do work.
> >
> > If you don't have SV8B's or are not running them in WB mode, then
> > I don't have any idea what has gone wrong...
>
> Ummmm. Ummmm.. that may explain a problem I have been seeing. :-)
>
> I have a pair of DX4/120's ("Enhanced"), one with IDE disk, one with 1542
> and SCSI disk. The one with SCSI disk is unhappy during big compiles (make
> world, etc). I haven't _noticed_ problems with the IDE disk. Same MB/cpu,
> etc.
>
> Rod, you seem to imply that by NOT running them in WB mode, the problem may
> not manifest itself (dependent upon the MB). Is this what you meant to
> imply?
Yes, that is exactly what I meant to imply.
> Can you recommend a good 486 motherboard (preferably PCI)?
Nope, IMHO, there are no _good_ 486 boards left on the market, the last
_good_ 486 PCI board I could get was the ASUS PCI/I-486SP3G and I have not
been able to get any more of them.
> Argh, I just got the fingers on my left hand wired to equipment in the next
> office.. hard to type..
>
> I noticed ASUS seems to have several other offerings besides the SP3G..
Such as what, the PVI-486AP4, out of production for 4 months, the only
486 board that I know ASUS is still makeing is the PVI-486SP3, which
I do not classify as a good board due to only 2 Simm sockets and if I
recall correctly a cache coherency problem in the Sis 496/497 chipset.
--
Rod Grimes rgrimes@gndrsh.aac.dev.com
Accurate Automation Company Reliable computers for FreeBSD
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