From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with archive (Exim 4.43) id 1Nz6vm-0000iA-OV for mharc-grub-devel@gnu.org; Tue, 06 Apr 2010 07:26:54 -0400 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1Nz6vk-0000hn-QP for grub-devel@gnu.org; Tue, 06 Apr 2010 07:26:52 -0400 Received: from [140.186.70.92] (port=36253 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1Nz6vj-0000hP-EW for grub-devel@gnu.org; Tue, 06 Apr 2010 07:26:52 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.69) (envelope-from ) id 1Nz6vi-0006p3-48 for grub-devel@gnu.org; Tue, 06 Apr 2010 07:26:51 -0400 Received: from mail.gmx.net ([213.165.64.20]:52592) by eggs.gnu.org with smtp (Exim 4.69) (envelope-from ) id 1Nz6vh-0006of-Mo for grub-devel@gnu.org; Tue, 06 Apr 2010 07:26:50 -0400 Received: (qmail invoked by alias); 06 Apr 2010 11:26:46 -0000 Received: from 165.126.46.212.adsl.ncore.de (HELO 192.168.2.69) [212.46.126.165] by mail.gmx.net (mp053) with SMTP; 06 Apr 2010 13:26:46 +0200 X-Authenticated: #2145628 X-Provags-ID: V01U2FsdGVkX19aweBfTYVahfDlgNRy0W8R79kGMFbGthYW6/3ljX orJfOYmLp8fEvO Date: Tue, 06 Apr 2010 13:26:00 +0200 From: "Thomas Schmitt" To: grub-devel@gnu.org References: <4BB74D95.2020002@gmail.com> In-Reply-To: <4BB74D95.2020002@gmail.com> Message-Id: <105894334819100@192.168.2.69> X-Y-GMX-Trusted: 0 X-FuHaFi: 0.55000000000000004 X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. Subject: Re: How to prepare an ISO 9660 CD for booting via GRUB ? X-BeenThere: grub-devel@gnu.org X-Mailman-Version: 2.1.5 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: Tue, 06 Apr 2010 11:26:53 -0000 Hi, i have roughly implemented the missing options of grub-mkisofs in xorriso and am now comparing the results. The ISO image by xorriso boots from CD and from USB stick. Are there other media types which would impose a further challenge ? If so: are there testers who would be willing to try my ISO image (1.9 MB) on such media ? ------------------------------------------------ It seems that grub-mkisofs does not comply much to the partition table prescription given by Vladimir. The image made by grub-mkisofs has 1550336 bytes = 757 * 2048 , 3028 * 512. It bears as partition table: 0000660 0080 0000700 0000 00cd 0000 0001 0000 ffff ffff 0000 0000720 0000 0000 0000 0000 0000 0000 0000 0000 * 0000760 0000 0000 0000 0000 0000 0000 0000 aa55 (od -x regrettably produces big-endian 16 bit. One has to swap: 00cd is actually cd 00 .) The xorriso image is currently a bit larger (see below). 1966080 bytes = 960 * 2048 , 3840 * 2048 xorriso -toc reports: ISO session : 1 , 32 , 754s , ISOIMAGE Partition table: Image size is 32 + 754 = 786 * 2048 = 3144 * 512 = 0x0C48 I insert 0x00000C47 as end LBA (= 0c47 0000). End C/H/S is c0,h49,s57 (= 31xx 0039). 0000660 0080 0000700 0002 31cd 0039 0001 0000 0c47 0000 0000 0000720 0000 0000 0000 0000 0000 0000 0000 0000 * 0000760 0000 0000 0000 0000 0000 0000 0000 aa55 Vladimir: does that look ok for you ? Is 0x0C47 correct to depict image size 0x0C48 ? Is my C/H/S computation ok ? (I understand Wikipedia that way, but am not sure.) ------------------------------------------------- xorriso produces a larger image because of 64 kB multi-session preparations, of 300 kB end padding and of padding to full 32 kB blocks. Most of this overhead can already be prevented. I will see whether i can strip the output to its net size of 754 sectors. Nevertheless, neither the image of grub-mkisofs nor of xorriso fit on a vanilla floppy disk. Is it worth to sacrifice multi-session history capabilities in order to save 64 kB ? (If i do not duplicate the ISO superblock then i cannot mount older sessions of a multi-session ISO image.) ------------------------------------------------ Compatibility question: Is the help text of grub-mkisofs --protective-msdos-label Patch a protective DOS-style label in the image essential to any frontend of grub-mkisofs ? I would prefer to print something more neutral. Like: --protective-msdos-label Patch System Area by partition table Any DOS connotation should be obvious by the option name already. ------------------------------------------------- Have a nice day :) Thomas