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Date: Sat, 14 Dec 1996 16:07:41 +1100
From: Bruce Evans <bde@zeta.org.au>
Message-Id: <199612140507.QAA26856@godzilla.zeta.org.au>
To: lada@ws2301.gud.siemens.co.at, yergeau@gloworm.Stanford.EDU
Subject: Re: 2.1.5-R kernel root on sd0 fails
Cc: hackers@freebsd.org
Sender: owner-hackers@freebsd.org
X-Loop: FreeBSD.org
Precedence: bulk

>>I had a happy installation with one SCSI disk and then had to add
>>a wd0--don't ask why.
>>
>>Subsequently I went to generate a new kernel in order to be able to
>>boot from sd0 without manual keyboard intervention every time.
>
>There doesn't appear to be a way to convince the biosboot to pass
>the "correct" information to the kernel (after all, both are bios
>drives).  Just putting "root on sd0" in the kernel config does not
>appear to work (the kernel still tries what it got from biosboot,
>sd1), but the following worked for me.

Three ways:
1. manual keyboard intervention every time.  Type something like
   1:sd(0,a)kernel
2. configure the boot blocks with the BOOT_HD_BIAS option.  Something
   like CFLAGS += -DBOOT_HD_BIAS=1.
3. configure the boot boot blocks with the NAMEBLOCK option and put
   the string in (1) in the nameblock using nextboot(8).  I haven't
   tried this.

>Put "root on sd1" and wire the SCSI drive to be sd1 (e.g. "disk sd1
>at scbus0 target 0").  You may also need to wire scbus0 to a
>particular controller (e.g. "controller scbus0 at ahc0").  See the
>LINT kernel config if you need more information on how to wire disk
>and controller targets.

This might be necessary if there are more drives and the BIOS drive
order is different than the FreeBSD drive order.

Bruce