Subject: Re: duo and ci boots
To: darrell pfeifer <PFEIFER@camins.Camosun.BC.CA>
From: Lawrence Kesteloot <>
List: macbsd-development
Date: 11/07/1993 17:08:25
> Well, given the si boot record of 7 grey bars,
> i thought you'd like to know that the nomath booter
> give 8 bars on a Duo 230, 12mb, 32bit mode, vm off.
> The bars run almost off the bottom of the screen,
> so who knows what 9 would do.


> I also tried the pre-nomath booter on my ci using
> internal video. It only gets 7 grey bars, so external
> video gets farther.

I believe (and this may be wrong because it's from memory) that the MMU
gets set to the new page tables just before grey bar #8.  Since the MMU
tables as they are now are telling the kernel that it is at physical
location zero (which it isn't on the si/ci), anything that you get
after that is code which is still in the cache.  As soon as the cache
runs out, it will try to fetch instructions from video memory, and will
crash (as you've noticed).  The number of grey bars after the 7th one
is pretty meaningless.  The key now is to change that MMU table setup
code in locore so that it knows about its physical load address.  This
shouldn't be too hard; I think it's stored in a register.