From owner-freebsd-questions  Thu Jul 31 08:24:01 1997
Return-Path: <owner-freebsd-questions>
Received: (from root@localhost)
          by hub.freebsd.org (8.8.5/8.8.5) id IAA15008
          for questions-outgoing; Thu, 31 Jul 1997 08:24:01 -0700 (PDT)
Received: from beowulf.utmb.edu (beowulf.utmb.edu [129.109.59.83])
          by hub.freebsd.org (8.8.5/8.8.5) with ESMTP id IAA14993
          for <questions@FreeBSD.ORG>; Thu, 31 Jul 1997 08:23:54 -0700 (PDT)
Received: (from bdodson@localhost)
	by beowulf.utmb.edu (8.8.5/8.8.5) id KAA01642
	for questions@FreeBSD.ORG; Thu, 31 Jul 1997 10:21:24 -0500 (CDT)
Date: Thu, 31 Jul 1997 10:21:24 -0500 (CDT)
From: "M. L. Dodson" <bdodson@beowulf.utmb.edu>
Message-Id: <199707311521.KAA01642@beowulf.utmb.edu>
To: questions@FreeBSD.ORG
Subject: Re: NT4, FBSD, different disks and booting
X-Sun-Charset: US-ASCII
Sender: owner-freebsd-questions@FreeBSD.ORG
X-Loop: FreeBSD.org
Precedence: bulk



Just to follow up with the final solution I settled on, here is one
way to at least avoid having to boot from a floppy.  Thanks to several
people who responded with suggestions.  Note that I reinstalled
NT and DOS 6.22 such that there is an initial DOS FAT file system
100MB in size with the rest of the disk being NT using NTFS.  I 
have not tested this solution on a 100% NTFS IDE boot disk (although
I think it should work there).  This is on FreeBSD 2.2.2 from the WC 
CDROM and NT 4.0 Workstation.

cd /usr/src/sys/i386/boot/biosboot and edit start.S to produce:

diff start.S start.S.orig
136a137
>	mov $0x81,%dl

make
cp boot.nohdr /msdos/bootsect.bsd # FAT partition is mounted on /msdos

Reboot to DOS and edit boot.ini as described in the FAQ to make a
FreeBSD boot option entry

ctrl-alt-del

Select the FreeBSD entry at the NT boot prompt.

At the FreeBSD boot prompt enter:

1:sd(0,a)kernel  (just like you were booting from a floppy)

FreeBSD comes up and finds its root partition correctly.  If you do
not enter:

1:sd(0,a)kernel 

at the FreeBSD boot prompt, the kernel panics because it cannot find 
its root partition (device probe works, though).

Not elegant, but I don't have to walk around to the other side of
my desk to insert/remove a FreeBSD floppy each time I reboot to the
other OS.

Of course, all the usual disclaimers about me not being responsible
if this incantation reformats your hard disk, etc. :)

Bud Dodson

> 
> On Fri, 25 Jul 1997, M. L. Dodson wrote:
> 
> > Mine is a quite common situation, I would think.  Description: a 
> > new PentiumPro, which, of course, comes with an IDE disk.  Not 
> > wanting to demean ;) FreeBSD by installing it on the IDE disk, I 
> > installed FBSD on an external 4 GB SCSI (not "dangerously 
> > dedicated", just the standard slice install).  NT 4.0 workstation 
> > is living on the whole IDE disk (I need to boot BT sometimes
> > to use Excel and Word).
> > 
> > I went to the FAQ to see how to setup the NT bootmanager to
> > handle the dual boot, where I see that the recipe only works if
> > both are on the same disk.  Aha, says I, I just need a customized
> > boot block.  So I went to the biosboot directory where I compiled
> > a bootblock with BOOT_HD_BIAS=1, substituted boot1 (obtained after
> > the make) for the boot block normally acquired via dd in the recipe, 
> > and still got a "no bootable partition" error, with no FBSD boot.  
> > 
> > Does anyone know how to handle this type of (likely quite common) 
> > situation?  Booting off a floppy is getting old fast.

--
M. L. Dodson                                bdodson@scms.utmb.edu
409-772-2178                                FAX: 409-772-1790