KERNEL NMI TRAP ON INTERACTIVE UNIX --- ANY SUGGESTIONS ?

[Heiko Blume]

lumpi at dobag.in-berlin.de (Joern Lubkoll) writes:

>hello,

>i use an Informtech 386- Motherboard with 33 mhz. The board is equipped
>with 16 Megabytes of Ram (4 MB SIMM on Board-80ns, 12 MB on Ram-Card in
>DIP - 70ns). After several minutes running interactive the Kernel dumps
>the Message:

>WARNING: Unknown NMI in System Mode - Unable to determine source of NMI

a parity error. if it happens more often you'll get something like

WARNING: Kernel NMI trap: unable to determine source of NMI 
Parity error at: 0x0059B000 (0x00402000, 0xC059B000)

NOTICE: Unexpected NMI in system mode!

eventually, but not always.

>If i degrade the board to 8 MB then the message won't occur !!! The Ram-
>Chips are all ok, because the board passes the memory test !

don't trust the el-cheapo bios ram tests. run somethink like checkit
(a DOS test program) for several days at least.

another cause can be setting the DMA speed and/or BUSON/OFF parameters
for adaptec (and others probably) scsi host adapters that do bus master
DMA. in this case no ram test will discover anything, of course.

be VERY careful with stuff like this, you can seriously f*ck up
your filesystem(s) when you get a NMI during dangerous operations
like superblock or fdisk table updates.
-- 
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