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Date: Tue, 22 Aug 1995 17:29:12 +1000
From: Bruce Evans <bde@zeta.org.au>
Message-Id: <199508220729.RAA28551@godzilla.zeta.org.au>
To: bde@zeta.org.au, msmith@atrad.adelaide.edu.au
Subject: Re: Using space in a DOS filesystem
Cc: hackers@freebsd.org
Sender: hackers-owner@freebsd.org
Precedence: bulk

>> You would need to have the vn device and various tools on the boot
>> device.  This is acceptable for demos and installations, but not so
>> good for use.

>But if the slab _is_ the boot device, how do we read the tools from it?

With difficulty.  Don't boot from it.

>Hmm. I'd have hoped that the partition table could be patched after it 
>was read by the kernel, to avoid having to rewrite the MBR every time 
>you booted.  (Or at least checking and stuffing the bogus slice back
>in if something 'smart' had tried to remove it.)

It would be relatively easy to check the partition once you have located
it.  You might be able to boot from the DOS file system, run some
utilities, mount an mfs root and create vn devices on it, mount the vn
file, and chroot() to a nicer file system.  I don't want the utilities
for this in the kernel.

>Ahu - how do you get slices of a vn device?  I presume it's just
>minor-magic?

First use the undocumented "labels" option to vnconfig to enable slices
and labels.  Then run fdisk to create slices and disklabel to create
labels as usual.

Bruce