From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from pigeon.gentoo.org ([208.92.234.80] helo=lists.gentoo.org) by finch.gentoo.org with esmtp (Exim 4.60) (envelope-from ) id 1NlkjF-0005vj-2e for garchives@archives.gentoo.org; Sun, 28 Feb 2010 15:06:45 +0000 Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id 45B53E0BDF for ; Sun, 28 Feb 2010 15:06:44 +0000 (UTC) Received: from karnak.local (cpc3-lutn10-2-0-cust648.9-3.cable.virginmedia.com [81.97.86.137]) by pigeon.gentoo.org (Postfix) with ESMTP id E2BB9E0BBD for ; Sun, 28 Feb 2010 14:12:46 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by karnak.local (Postfix) with ESMTP id 7FEC218003 for ; Sun, 28 Feb 2010 14:12:46 +0000 (GMT) X-Virus-Scanned: by amavisd-new using ClamAV at karnak.local Received: from karnak.local ([127.0.0.1]) by localhost (karnak.local [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 9Tih7rxsdMx6 for ; Sun, 28 Feb 2010 14:12:44 +0000 (GMT) Received: from karnak.local (localhost [127.0.0.1]) by karnak.local (Postfix) with ESMTP id C9A3618002 for ; Sun, 28 Feb 2010 14:12:44 +0000 (GMT) Date: Sun, 28 Feb 2010 14:12:38 +0000 From: David W Noon To: gentoo-user@lists.gentoo.org Subject: Re: [gentoo-user] Re: Who believes in cylinders? Message-ID: <20100228141238.4d92fc58@karnak.local> In-Reply-To: References: Organization: Luton Operatic Society X-Mailer: Claws Mail 3.7.5 (GTK+ 2.16.6; i686-pc-linux-gnu) Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-user@lists.gentoo.org Reply-to: gentoo-user@lists.gentoo.org Mime-Version: 1.0 Content-Type: multipart/signed; micalg=PGP-SHA1; boundary="Sig_/g858=jPVm9Y1oV5mra635kO"; protocol="application/pgp-signature" X-Archives-Salt: d7be531a-af7f-41dd-b66b-d6066cc0005d X-Archives-Hash: cd3483fd9004a8028a79bf4f81bc4ee9 --Sig_/g858=jPVm9Y1oV5mra635kO Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable On Sun, 28 Feb 2010 13:10:02 +0100, Mick wrote about Re: [gentoo-user] Re: Who believes in cylinders?: >On Saturday 27 February 2010 18:20:24 Etaoin Shrdlu wrote: >> On Saturday 27 February 2010, BRM wrote: >> > Stage 1 focuses solely on loading Stage 2, >> > and has historically been limited to a total size[1] to 512 bytes, >>=20 >> It's actually less than that, because the first 64 bytes of sector 0 >> contain the partition table, so the maximum size of a stage1 >> bootloader is 510 - 64 =3D 446 bytes. > >Yep, that's why dd if=3D/dev/sda of=3D~/partition_table.img bs=3D446 count= =3D1 >will make you a nice back up of your partition table, Actually, it will backup your primary bootstrap code. Try: dd if=3D/dev/sda of=3D~/partition_table.img bs=3D1 skip=3D446 count=3D64 Note that you will need to be root or in the "disk" group (or equivalent on your system), so that you have access to /dev/sda as a raw device file. [As ever, sudo is your friend.] Also note that this backup will only contain the primary partitions and any extended partition on that disk; all the logical drives within the extended partition are mapped by secondary partition tables in their local bootstrap records (LBRs). This makes for a more complicated process to backup the complete partition table for the disk. Worse still, all of my machines have at least 4 hard drives -- some as many as 7. So this process has to be repeated for each physical disk. Many years ago I wrote an OS/2 program to handle all of this. Perhaps I should blow the dust off it, convert it to use POSIX functions and publish it as FOSS. > while bs=3D512 will back up your complete MBR. True. --=20 Regards, Dave [RLU #314465] =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D dwnoon@ntlworld.com (David W Noon) =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --Sig_/g858=jPVm9Y1oV5mra635kO Content-Type: application/pgp-signature; name=signature.asc Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.14 (GNU/Linux) iEYEARECAAYFAkuKedwACgkQ9MqaUJQw2MmvYgCfXRmFMdz2Vz57+NNJe2oEPX2Z ltYAnRFmOMadZfTNMYe2mYxlUiy8XOOS =pV30 -----END PGP SIGNATURE----- --Sig_/g858=jPVm9Y1oV5mra635kO--