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Date: Thu, 10 Dec 2009 03:12:45 +0100
From: Polytropon <freebsd@edvax.de>
To: Maxim Khitrov <mkhitrov@gmail.com>
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Cc: freebsd-questions@freebsd.org
Subject: Re: Dangerously Dedicated
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On Wed, 9 Dec 2009 20:41:40 -0500, Maxim Khitrov <mkhitrov@gmail.com> wrote:
> On Wed, Dec 9, 2009 at 8:33 PM, Rolf Nielsen
> <listreader@lazlarlyricon.com> wrote:
> > As far as I understand it, it's called Dangerously Dedicated because it may
> > cause other systems not to recognise the disk. Consequently, newfs'ing a
> > slice without first partitioning it can hardly be DD, since that is what
> > other systems do, right?
> 
> That is correct. That slice will not be bootable, but you can use it
> to store data.

Being bootable is a matter of what the MBR boot block
says. In a DD setting, it refers to the first partition
(that's not within a slice), e. g. ad0a. Especially in
a multi-OS setting, the use of slices seems to be
strongly recommended so all operating systems behave
in the required way (due to compatibility reasons,
see "DOS primary partitions"), which limits the number
of slices to 4.

For plain storage, it's not needed to encapsulate the
partition with the file system inside a slice, e. g.

	ad1  ad1s1  ad1s1e
	{    [      (/data)  ]  }

in comparison to

	ad1  ad1c
	{    (/data)  }

And as it is known, the "c" can be omitted, as in

	# mount /dev/ad1 /data



-- 
Polytropon
Magdeburg, Germany
Happy FreeBSD user since 4.0
Andra moi ennepe, Mousa, ...