Subject: Re: bootblock problems
To: None <>
From: Louis A. Mamakos <louie@TransSys.COM>
List: current-users
Date: 01/24/1994 23:48:29
I have NetBSD-current (as of a week or so ago) running on a 25MHz
386SX system without any major problems.  I've been "borrowing" it
from my wife, with the intent of using it to bootstrap my system..

I've been having problems getting NetBSD-current booted on a Zenith
Znote 433Ln+ laptop.  This is a 33MHz 486SL, 4MB memory, 200 MB IDE
hard disk.  So far, the problem seems to be in the bootblock.  

When I try to boot from the floppy, it doesn't get very far and then
resets and begins again.  Compiling the boot code with -DDEBUG results in


and then it restarts the boot process.  I starting dropping in HLT instructions 
to see how far it gets.. it seems that the seconds part of the boot block gets
loaded, but it doesn't get past this hunk of code in boot2.S:

	/* finished with groping in real mode segments */
	pop	%es

	/* change to protected mode */
	call	EXT(real_to_prot)

this is just after its frobbed the GDT and directly before it clears
BSS.  I dropped some HLTs in the real_to_prot function, and it seems
that its going off into the weeds somewhere in there.

It's almost like the IDT or GDT didn't get set up properly, and it
takes a wild leap when protected mode is turned on.

 - - - - -

Now, to complicate things a bit further, I can take the boot block off the 5.25"
floppy that I booted the 386SX system with, and it gets further!  This is a much
older boot block $Revision 1.8 $ or so.  With this version, it prints the 

>> NetBSD 0.9 ...
Boot: ..

prompts, but never accepts keyboard input...

Does this ring a bell for anyone at all?  Its sort of driving me nuts and
is particularlly hard to debug as well.