From owner-freebsd-questions@FreeBSD.ORG Fri Nov 16 14:07:08 2012 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id DD178EC7 for ; Fri, 16 Nov 2012 14:07:08 +0000 (UTC) (envelope-from dweimer@dweimer.net) Received: from webmail.dweimer.net (24-240-198-187.static.stls.mo.charter.com [24.240.198.187]) by mx1.freebsd.org (Postfix) with ESMTP id 86D698FC13 for ; Fri, 16 Nov 2012 14:07:07 +0000 (UTC) Received: from www.dweimer.net (webmail.dweimer.net [192.168.5.1]) by webmail.dweimer.net (8.14.5/8.14.5) with ESMTP id qAGE71VG005714 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO) for ; Fri, 16 Nov 2012 08:07:01 -0600 (CST) (envelope-from dweimer@dweimer.net) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Date: Fri, 16 Nov 2012 08:07:01 -0600 From: dweimer To: Subject: Re: Advanced Format Drive =?UTF-8?Q?=3F?= Organization: dweimer.net Mail-Reply-To: In-Reply-To: <26514.1353022306@tristatelogic.com> References: <26514.1353022306@tristatelogic.com> Message-ID: <46dc11a33f41ccb597efc1f2efb94403@dweimer.net> X-Sender: dweimer@dweimer.net User-Agent: Roundcube Webmail/0.8.1 X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list Reply-To: dweimer@dweimer.net List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 16 Nov 2012 14:07:09 -0000 On 2012-11-15 17:31, Ronald F. Guilmette wrote: > (This stuff would probably be a lot less confiusing if I actually > knew > what I was doing, but...) > > OK, Warren, I've just done the following steps. The first two I drew > from the manpage examples, and then followed those up with two > commands > from your tutorial. > > /sbin/gpart create -s GPT ada0 # manpage example is wrong, ad0 > -> ada0 > /sbin/gpart bootcode -b /boot/mbr ad0 # manpage wrong again, pmbr > -> mbr > gpart add -t freebsd-boot -l gpboot -b 40 -s 512K ada0 > gpart bootcode -b /boot/pmbr -p /boot/gptboot -i 1 ada0 > > That last one, done at the suggestion of your tutorial page, has me > completely perplexed, because of what is said, very explicitly, in > the > gpart(8) manpage: > > bootcode Embed bootstrap code into the partitioning scheme's > metadata on > the geom (using -b bootcode) or write bootstrap code > into a > partition (using -p partcode and -i index). > > Please note the use of the word "or". > > The man page is telling me to _either_ use the -p option _or else_ > use > the -p and -i options together. But you are telling me to use all > three > in one go! > > Forgive me, but I'm confused. (As you can tell by now, I am often > easily > confused. Sorry.) > _______________________________________________ > freebsd-questions@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to > "freebsd-questions-unsubscribe@freebsd.org" I saw this, and well started wondering myself, as I have been using this while doing work on booting FreeBSD via ZFS (of course using -p /boot/gptzfsboot), I got the line from a tutorial on booting from ZFS. Never thought much of it, until now, but I believe I see now why, the secret is the pmbr, notice the "p". Its the protective mbr, it lets formatting tools that understand mbr, but not gpart know that there is something there, the actual boot code is in the partition. -- Thanks, Dean E. Weimer http://www.dweimer.net/