From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with archive (Exim 4.43) id 1J5zNb-0000BM-Ot for mharc-grub-devel@gnu.org; Sat, 22 Dec 2007 03:06:43 -0500 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1J5zNa-00008W-5a for grub-devel@gnu.org; Sat, 22 Dec 2007 03:06:42 -0500 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1J5zNY-00006t-Po for grub-devel@gnu.org; Sat, 22 Dec 2007 03:06:41 -0500 Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1J5zNY-00006c-L7 for grub-devel@gnu.org; Sat, 22 Dec 2007 03:06:40 -0500 Received: from mx20.gnu.org ([199.232.41.8]) by monty-python.gnu.org with esmtps (TLS-1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1J5zNY-0002Rt-1z for grub-devel@gnu.org; Sat, 22 Dec 2007 03:06:40 -0500 Received: from ns39764.ovh.net ([91.121.25.85] helo=nexedi.com) by mx20.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1J5zNW-0002le-Px for grub-devel@gnu.org; Sat, 22 Dec 2007 03:06:38 -0500 Received: from [10.8.0.46] (unknown [10.8.0.46]) by nexedi.com (Postfix) with ESMTP id CF3A13EB23 for ; Sat, 22 Dec 2007 09:10:30 +0100 (CET) From: "Yoshinori K. Okuji" Organization: enbug.org To: The development of GRUB 2 Date: Sat, 22 Dec 2007 09:06:32 +0100 User-Agent: KMail/1.9.4 References: <20071221190450.GA23118@thorin> In-Reply-To: <20071221190450.GA23118@thorin> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200712220906.33867.okuji@enbug.org> X-detected-kernel: by mx20.gnu.org: Linux 2.6 (newer, 3) X-detected-kernel: by monty-python.gnu.org: Linux 2.6, seldom 2.4 (older, 4) Subject: Re: Creating grub/grub2/grldr.mbr bootrom with makerom X-BeenThere: grub-devel@gnu.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: The development of GRUB 2 List-Id: The development of GRUB 2 List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 22 Dec 2007 08:06:42 -0000 On Friday 21 December 2007 20:04, Robert Millan wrote: > How well does compression work for GRUB 2 ? core.img is already compressed > (with lzo); if LZMA makes better results perhaps it'd be a good idea to > switch. It's not that simple. LZO was chosen instead of gzip, because of the size requirement on PC. To preserve safety, we need to keep the core part less than 31.5KB (63 sectors). The size is the sum of non-compressable bootstrap code, decompression code and compressed code + data. When I made an experiment in PUPA, although gzip had a better compression ratio, due to the decompression code size, LZO won. I don't know precisely, but I suspect that decompression code for LZMA would be slightly larger than gzip's (IIRC, a range coder is likely to require more code and data). So I don't expect that LZMA can replace the current usage of LZO in normal PC so easily. Okuji