From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with archive (Exim 4.43) id 1GrGvB-0000hy-8l for mharc-grub-devel@gnu.org; Mon, 04 Dec 2006 11:44:01 -0500 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1GrGv8-0000hm-VM for grub-devel@gnu.org; Mon, 04 Dec 2006 11:43:59 -0500 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1GrGv7-0000ha-2N for grub-devel@gnu.org; Mon, 04 Dec 2006 11:43:57 -0500 Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1GrGv6-0000hX-T9 for grub-devel@gnu.org; Mon, 04 Dec 2006 11:43:56 -0500 Received: from [32.97.182.141] (helo=e1.ny.us.ibm.com) by monty-python.gnu.org with esmtps (TLS-1.0:DHE_RSA_AES_256_CBC_SHA:32) (Exim 4.52) id 1GrGv6-000438-WE for grub-devel@gnu.org; Mon, 04 Dec 2006 11:43:57 -0500 Received: from d01relay04.pok.ibm.com (d01relay04.pok.ibm.com [9.56.227.236]) by e1.ny.us.ibm.com (8.13.8/8.12.11) with ESMTP id kB4GhsY3005661 for ; Mon, 4 Dec 2006 11:43:54 -0500 Received: from d01av04.pok.ibm.com (d01av04.pok.ibm.com [9.56.224.64]) by d01relay04.pok.ibm.com (8.13.6/8.13.6/NCO v8.1.1) with ESMTP id kB4Ghq1J194056 for ; Mon, 4 Dec 2006 11:43:54 -0500 Received: from d01av04.pok.ibm.com (loopback [127.0.0.1]) by d01av04.pok.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id kB4GhpLL001160 for ; Mon, 4 Dec 2006 11:43:51 -0500 Received: from [9.53.41.42] (basalt.austin.ibm.com [9.53.41.42]) by d01av04.pok.ibm.com (8.12.11.20060308/8.12.11) with ESMTP id kB4Ghphl001106 for ; Mon, 4 Dec 2006 11:43:51 -0500 From: Hollis Blanchard To: The development of GRUB 2 In-Reply-To: <200612021827.31945.okuji@enbug.org> References: <1163545104.12931.49.camel@basalt> <200611250525.00823.okuji@enbug.org> <877ixa2rwd.fsf@xs4all.nl> <200612021827.31945.okuji@enbug.org> Content-Type: text/plain Date: Mon, 04 Dec 2006 10:43:39 -0600 Message-Id: <1165250619.30343.17.camel@basalt> Mime-Version: 1.0 X-Mailer: Evolution 2.8.1 Content-Transfer-Encoding: 7bit Subject: Re: multiboot2: make multiboot header optional 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: Mon, 04 Dec 2006 16:43:59 -0000 On Sat, 2006-12-02 at 18:27 +0100, Yoshinori K. Okuji wrote: > > Reversely, I ask you a question. What is the real advantage in using > tags in a Multiboot header? > > From my point of view, it is not necessarily very extensible or > flexible, as our experience shows that changes to the Multiboot header > are rarely demanded (so far, only once, IIRC). It should be pretty clear that 32 bits are a finite number, and tags are unlimited. In fact it's worse than that, since the bit partitioning means we have far fewer available bits for any particular flag. The bit numbering is also confusing, especially the partitioning of meanings (this is required, this is requested, this is arch-specific, this isn't). Finally, using flags for some things and tags for others is inconsistent. The extensibility argument alone is enough to seal it for me, especially since the code can be written in such an error-free manner, as I've demonstrated. -Hollis