
GUS Programmer's Digest     Wed Jul 21 00:07     Volume 2: Issue  25  

Today's Topics:
                                 NMI

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Date: Tue, 20 Jul 93 03:36:30 GMT
From: thomasvk@blackhl.hacktic.nl (Thomas van Kuipers)
Subject: NMI
Message-ID: <JFBe8B7w165w@blackhl.hacktic.nl>

I post this here also, because NMI is a very hardware/software/prog.-ware 
related problem.
Here the msg:

Hi Phil,
 
In your letter to the gus digest:
 
" Date: Thu, 15 Jul 1993 09:40:04 -0500 (CDT)
From: Phil Johnson <hands@seahorse.micro.umn.edu>
Subject: NMI problems
Message-ID: <Pine.3.03.9307150904.A4551-b100000@seahorse.micro.umn.edu>
 
lacking of the NMI procedure on the SBOS prg.. BUT... my puter (a DX2-66
on a VLFSD [?] v1.0 board, Intel chips) was running a-O.K. with SBOS,
UNTIL.. about a few days ago, it suddenly gave me the NMI error, and I am
really upset!  
  I did not install a thing, nor did I mess with my motherboard, open the
CPU case, or screw with CMOS.. I powered it on one day and SBOS just
didn't work. ..."
 
You mentioned how you called a techian and told you that it 
never worked in the first place. He must have been referring 
to that a problem under dos can be not harmful at one moment 
and at another moment be harmful. It's the same with your 
interrupt setting who might be conflict full(especially when 2 
things are on one interupt, like modems and sound blaster),
but works with dos and then os/2 doesn't works or gives errors.
(a hidden problem thus)
 
Know Nmi .... I know (also from digest and other sources) that 
SBOS tries to get hooked to the NMI (the ONLY NMI interupt in 
the computer is IRQ 0 ! which is been used by the memory ...). 
Irq0 is used to fresh up the Dynamic RAM. For a reason me not 
known, the gravis / Ford programmers find it usefull or so to 
hook up SBOS to IRQ 0 (the told the had to use it, because it 
HAS to intercept, in all circumstances, the computer to 
emulate SB). 
 
I had this a few times in a OS/2 DOS box (The NMI procedure on
 this P.C. is disabled.) and so on i assume os/2 get a hold of 
that too (it only accured when i ran 2 dos box'en with sbos or 
when i closed a dos box with sbos on and then opened it and 
tried to run sbos).
 
It can have to do with your memory manager (qemm, emm, max), 
but it works fine by me with qemm and emm or neither. Also i 
don't have a dx2 or VLB (you said VLFSD v1.0, but i think you 
mean Vesa Local Bus (no you mean VLSI chips ? if so .. VLSI 
are large Scale chips with much transitors). 
 
As far as i know the message has nothing to do with cpu/open 
computer/or cmos. One thing you could check: Do you have the 
I/o bus TO fast, i mean stand it on 8MHZ (some card don't like 
to fast i/o card .. i don't think it is the solve, but who 
knows).
 
Sorry for the long letter, but i hope you understand more of 
it know. Also sorry for not having a direct answer to the 
problem. Best try to get the computer booted with NO drivers 
in config.sys/autoexec.bat except RIGHT set parameters.  

Thomas

------------------------------

End of GUS Programmer's Digest V2 #25
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