From: torvalds@klaava.Helsinki.FI (Linus Torvalds) Subject: Re: 0.99.8 kernel panic ... Date: Wed, 21 Apr 1993 13:15:30 GMT
In article <1993Apr21.125410.7667@klaava.Helsinki.FI> laakkone@klaava.Helsinki.FI (Tero Laakkonen) writes:
>
>i did this just before lunch time and booted my new (0.99.8 with 4.3.3
>dlls and tcp/ip) kernel. when
>i came back to my machine after lunch, the screen was full of general
>protection faults and messages from the swapper about not being able to
>free something.
>
>when i tried to do some fsck's, it said uhhoh, got a DMI ...
>
>i tried to do a couple of boots, even with my non-tcp kernel, it still
>got DMI's/general protection errors ... even got a SYSTEM HALTED ...
Does "DMI" by any chance actually mean "NMI"? That's a "NonMaskable
Interrupt", and usually means that you have *some* kind of memory
problems. Also, the SYSTEM HALTED message would seem to indicate this:
that's not even a linux message, but a DOS/BIOS one (I assume this
happened at bootup).
Check that all your SIMMs are cleanly seated, and try out some
memory-test program under DOS. Note that linux uses memory much more
intensively than even most memory testers under DOS seem to do (32-bit
accesses all the time, all over memory and in largely unpredictable
patterns..), so even if a memory tester doesn't find anything, it
doesn't actually prove your memory is ok (but if you get the SYSTEM
HALTED message, even a DOS memory tester is likely to find *something*).
>i'm all at sea. this is the first time this kind of thing has happened
>to me with linux. tell me it's an easy-to-fix hardware bug.
Easy to fix: not necessarily. Re-seat your SIMMs to make sure there are
no bad contacts, and if you have spare SIMMs lying around (it does
happen..), try exchanging them. On a 8MB machine, you can usually find
the buggy SIMM by removing 4MB and trying different combinations of
SIMMs until you've narrowed the problem down. Even this may not work:
I've heard of cases where the motherboard works fine with every
combination of 4MB SIMMs imaginable, but breaks with marginal SIMMs in
the higher area ("bank 1" on most motherboards).
Linus