Subject: Why does my machine crash?
To: None <netbsd-help@netbsd.org>
From: Brett Lymn <blymn@awadi.com.AU>
List: netbsd-help
Date: 11/27/1994 19:56:32
Folks,
        Some of you may remember I complained about my machine
crashing before on this list.  The advice was to get a later version
of NetBSD.  I took this advice and have NetBSD 1.0 on my machine.  The
bummer was that my machine still crashed when I thrashed the SCSI
disks.  These were the errors I was getting:

vmfault(f86bea00, 0, 1, 0) -> 1
fatal page fault in supervisor mode
trap type 6 code 0 eip f8123aff cs 8 eflags 10292 cr2 12 cpl 0
panic: trap
syncing disks ...
sddump()   -- not implemented
vmfault(f86bea00, 7ffff000, 1, 0) -> 1
fatal page fault in supervisor mode
trap type 6 code 7fff0000 eip f8129adb cs f8120008 eflags 10246 cr2 7fffffff cpl f8129a5c
panic: trap

I played around with disabling the internal and external caches
without any effect.  I tried changing the DMA speed but that just hung
things (according to some utility I have the DMA is 11us on/4 us off
which translates to 6.7Mhz DMA to me but I don't seem to be able to
change this).  Anyway, I remembered somone posting on the usenet news
that there was some memory clash between the adaptec card and memory
in the region > 15Meg.  On this basis I removed 4Meg from my machine
(the minimum I could remove) to make my memory 12Meg.  Now things
work!  I have unpacked the X11R6 stuff without a hitch and now I am
compiling without problems.  The machine appears to be rock solid.
Can anyone shed any light on this phenonem?  It really hurts losing
4Meg :-(

Machine details:

486DX/25Mhz Micronics motherboard with 16Meg (now 12Meg) of RAM
Adaptec AHA1542B SCSI controller with Wren VII and Maxtor LXT213 disks
DTC ESDI controller with Wren V disk
Wangtek QIC02 QIC tape drive
a couple of generic serial cards
ET4000 chipset VGA card

OS: NetBSD 1.0 - no patches.

-- 
Brett Lymn, Computer Systems Administrator, AWA Defence Industries
===============================================================================
"Aha!  Pronoun problems.  It's not `shoot you, shoot you', it's `shoot me,
 shoot me'.  So, go ahead, shoot ME, shoot ME <BLAM>... You're Despicable"
                        -- Daffy Duck