$#%&%%$ 286 Dos Merge

[Michael Grenier]

>From article <1893 at qetzal.UUCP>, by rcw at qetzal.UUCP (Robert C. White):
> I am using version 1.30 of Dos Merge on my 286.  I find that I 
> still (after six months) cannot run the software with my machine
> running at 10 mhz.  Does anyone have any bright ideas?  Typically,
> the machine runs ok for five or ten minutes, then comes crashing
> down with a general protection/double panic.  Everything works fine
> at 6 mhz, but the machine is a real dog.


OK, the machine runs good at slow speed but fails at higher speed...
Hmmm, doesn't really sound like a software problem to me. (I'm
biased because I've been running DosMerge v1.3 at 10 Mhz for many months
now). How does the system run with the regular kernel?

> 
> Configuration:
> 
> 	Genoa EGA card with 256k of memory
> 	Phoenix Bios, Release 3.01.
> 	Everex extended memory card
> 	No name serial ports (2).
> 	IMS/286 Box. (Intelligent Micro Systems).
> 
> 	This other stuff is attached to the machine, but I
> 	experienced the same problem before they were added:
> 
> 	Everex 60 meg cartridge tape backup (QIC-36) IRQ5,DMA3
> 	Overland Data Qualstar Reel Tape    	     IRQ7,DMA1
> 	Hitachi CD-ROM Drive (Anyone have a uport driver for this?)
> 	
>

I see that you're using the printer interrupts.  When in use by your
devices, are the lp drivers disabled? If you are using the Overland
device with their new Microport drivers than you should remember to
remove that corrosponding lp driver from the kernel - vector 39 for the
lp line in the file 'master' in the linkkit.  The same goes for the
Everex device (vector 37). 

If you are accessing these devices from DOS, are you sure they do not
interrupt when not in use? Are you assigning the interrupts before
using them from the Dos options or configuration? I'm really uncomfortable
if you haven't removed the interrupt references to the printer drivers
from the kernel.
 
> The only thing I noticed that was wierd about this machine is that
> I had to put exactly 640k of 120-ns ram chips on the motherboard.
> There are 512k of 256k drams and 128k of 64k drams.  All chips are
> rated at 120ns.  When I tried to put 1 megabyte on the motherboard,
> all kinds of memory errors would result.
>

I assume you moved the starting address of the Everex extended memory
card. If this is the 3 megabyte card with support for expanded memory,
it should work great at 10 Mhz under DOSMerge. I've tested it! 
I further assume that you are runnning with one wait state.
Who knows if that EGA card will handle 10 Mhz?
 
In summary, I very much doubt that DosMerge is at fault here.  Its
either in the hardware configuration (devices like the RAM or EGA not
taking 10Mhz well) or the configuration of DosMerge and the handling of
interrupts. Another thing, DosMerge uses lots of memory - perhaps
high RAM doesn't like the speed. Do you ever see the NMI error?
My system used to panic also until I found a bad RAM card.

Please run the system awhile with the regular kernel.

-Mike Grenier
{ihnp4???, rutgers, amdahl}!bungia!cimcor!mike
mike at cimcor.mn.org