From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from list by lists.gnu.org with archive (Exim 4.71) id 1VcxNV-0003CV-Cz for mharc-grub-devel@gnu.org; Sun, 03 Nov 2013 08:06:05 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54611) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VcxNO-0003CH-UO for grub-devel@gnu.org; Sun, 03 Nov 2013 08:06:04 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VcxNJ-0003lc-IV for grub-devel@gnu.org; Sun, 03 Nov 2013 08:05:58 -0500 Received: from mail-ee0-x236.google.com ([2a00:1450:4013:c00::236]:64989) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VcxNJ-0003lU-An for grub-devel@gnu.org; Sun, 03 Nov 2013 08:05:53 -0500 Received: by mail-ee0-f54.google.com with SMTP id c50so593828eek.41 for ; Sun, 03 Nov 2013 05:05:52 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=message-id:date:from:user-agent:mime-version:to:subject:references :in-reply-to:content-type; bh=FOezAisg8uE5Klws6xJ5L2IF0HPl12ntez5Sv0NgWWY=; b=Tb57lQN9HZCGIAJAMm544zHxGx2AQWrcGFifw448MOGBaJzVk1Pgu7bp6Gd35NPTLA b2Zjsc3GJyuPrHCCcZtiCG2J4X4q3OtBAP1s/U3/9a/uyOu+1WLIVhkVcieBNIloebb5 vXzFP+OCntP1hywIb4UplKUX7CkiDd99tGmRlO/ftckqJblkYPXNAKCcTnveRmqN9Qvl oXpQd0DwwB6qSIX16IMGUWIcy3ExFFryOdsW+OND1nIxkQ46bt7O76ibMrhXRyejpnWU FFbQt8bVpJI7/hWl68h/1OKGBQXt8h+ljFO4IDIOfp0lUZobs8gOy3eKpqE5qTRb88IS BPkw== X-Received: by 10.14.45.70 with SMTP id o46mr12917144eeb.19.1383483952539; Sun, 03 Nov 2013 05:05:52 -0800 (PST) Received: from [192.168.1.16] (31-249.1-85.cust.bluewin.ch. [85.1.249.31]) by mx.google.com with ESMTPSA id d7sm33210151eem.8.2013.11.03.05.05.51 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Sun, 03 Nov 2013 05:05:51 -0800 (PST) Message-ID: <52764A2E.5050701@gmail.com> Date: Sun, 03 Nov 2013 14:05:50 +0100 From: =?UTF-8?B?VmxhZGltaXIgJ8+GLWNvZGVyL3BoY29kZXInIFNlcmJpbmVua28=?= User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20131005 Icedove/17.0.9 MIME-Version: 1.0 To: grub-devel@gnu.org Subject: Re: How important is the MBR partition offset of grub-mkrescue ? References: <52758DFE.3030604@gmail.com> <2627651367660158335@scdbackup.webframe.org> In-Reply-To: <2627651367660158335@scdbackup.webframe.org> X-Enigmail-Version: 1.5.1 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="----enig2QVUXTJNCQESNBNXLSQXB" X-detected-operating-system: by eggs.gnu.org: Error: Malformed IPv6 address (bad octet value). X-Received-From: 2a00:1450:4013:c00::236 X-BeenThere: grub-devel@gnu.org X-Mailman-Version: 2.1.14 Precedence: list Reply-To: The development of GNU GRUB List-Id: The development of GNU GRUB List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 03 Nov 2013 13:06:04 -0000 This is an OpenPGP/MIME signed message (RFC 4880 and 3156) ------enig2QVUXTJNCQESNBNXLSQXB Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable >=20 > This yields an MBR (copied from $old_iso) with partition start > LBA 64 (16 blocks of 2048) Hm, that would mean that some crapware like adobe might write between MBR and first partition. >=20 > My test machine boots via BIOS. The ISO image is only equipped > for BIOS, anyway. I have no means to test UEFI with partition > offset 16. >=20 > Does contemporary grub-mkrescue cause xorriso to produce GPT > for UEFI ? (That would be a new adventure with -partition_offset.) >=20 Yes, and we add HFS+ as well. Isn't this HFS+ catalog sufficient for the problem at hand? >=20 > If anybody has opportunity and curiosity: >=20 > It should be possible to append option -partition_offset 16 > to the options of grub-mkrescue, so that it reaches xorriso > as one of the ${source} arguments. >=20 > There was a bug with -partition_offset with older versions > of xorriso, which caused Debian to stop using this option > in its amd64 UEFI capable images. So better get newest stable > xorriso for such a test. Currently this is: > http://www.gnu.org/software/xorriso/xorriso-1.3.2.tar.gz > Can we detect presence of this bug? >=20 > Theoretical problems: >=20 Additional problem you don't mention: consumption of space by additional headers. We use xorriso for making floppies as well (and it works). > El Torito booting from CD/DVD should not be influenced by > this unusual layout. The ISO 9660 image beginning at LBA 0 > is quite the same as without that option. >=20 > Nevertheless, there was a report that Apple "Snow Leopard" > refused to mount an ISO image with partition offset 16. > http://lists.debian.org/debian-cd/2011/04/msg00032.html > http://lists.debian.org/debian-cd/2011/04/msg00040.html > http://lists.debian.org/debian-cd/2011/04/msg00042.html > Note well that this was not about booting. >=20 But it will most likely swallow HFS+-hybrid disk without any problem. Perhaps we should generate HFS+-hybrid even for BIOS-only CDs. Another solution is to have a hybrid ISO + FAT or ISO + HFS+ + FAT layout= s. > Further, one never knows what the booting operating system > expects as layout of USB sticks. I consider the current layout > with LBA 1 to be more confusing. But that's only me ... >=20 The reason for the specified partition is twofold: - Some computers check for presence of an active partition. - To avoid some software overwriting the ISO If user desires to have a partition for data he can always add a second partition but it doesn't solve the problem of accessing ISO files. >=20 > Have a nice day :) >=20 > Thomas >=20 >=20 > _______________________________________________ > Grub-devel mailing list > Grub-devel@gnu.org > https://lists.gnu.org/mailman/listinfo/grub-devel >=20 ------enig2QVUXTJNCQESNBNXLSQXB Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.15 (GNU/Linux) Comment: Using GnuPG with Icedove - http://www.enigmail.net/ iF4EAREKAAYFAlJ2Si4ACgkQNak7dOguQgk1ZAD/R4sk7Msj94T+2gYgXLEudbI3 ueasNrG6zOR0fc+RHmoA/Rlhxkl75sUuxt5DarpCLSfLcLE/Oa5t6Yf2n9rdi1wx =Da6M -----END PGP SIGNATURE----- ------enig2QVUXTJNCQESNBNXLSQXB--