From owner-freebsd-hackers@FreeBSD.ORG Mon Apr 14 09:00:33 2003 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id CC27B37B404; Mon, 14 Apr 2003 09:00:33 -0700 (PDT) Received: from faui40.informatik.uni-erlangen.de (faui40-smtp.informatik.uni-erlangen.de [131.188.34.40]) by mx1.FreeBSD.org (Postfix) with ESMTP id 8C54243F85; Mon, 14 Apr 2003 09:00:31 -0700 (PDT) (envelope-from eckert@faui40p.informatik.uni-erlangen.de) Received: from faui40p.informatik.uni-erlangen.de (faui40p.informatik.uni-erlangen.de [131.188.34.77]) id SAA16177; Mon, 14 Apr 2003 18:00:29 +0200 (MEST) Received: (from eckert@localhost) by faui40p.informatik.uni-erlangen.de (8.9.3/8.1.6-FAU) id SAA21075; Mon, 14 Apr 2003 18:00:29 +0200 (MEST) From: Toerless Eckert Message-Id: <200304141600.SAA21075@faui40p.informatik.uni-erlangen.de> In-Reply-To: from John Baldwin at "Apr 14, 2003 10:36:55 am" To: jhb@FreeBSD.org (John Baldwin) Date: Mon, 14 Apr 2003 18:00:28 +0200 (MEST) Organisation: CSD IMMD IV, University of Erlangen, Germany X-Mailer: ELM [version 2.4ME+ PL42 (25)] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit cc: freebsd-hackers@FreeBSD.org cc: eckert@i4.informatik.uni-erlangen.de Subject: Re: boot2 broken ? (booting from pst fails) X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 14 Apr 2003 16:00:34 -0000 > > - Why is the BIOS routine not run in real mode ? Would it be hard trying > > to change BTX so that it executes the interrupt in real mode ? > > Yes. Not to mention lack of space in boot2 for BTX to grow to support this. With boot2 being space challenged, why does it need to be a btx client anyhow ? > > - Is there actually a requirement for a BIOS to work correctly > > in virtual mode ? I was under the assumption that BIOS is always > > only assumed to need to work correctly in real mode. If this is > > not true, then i would welcome if you could point me to an official > > PC98, .. (or whatever) document WIntel , or > > whoever leads the conspiracy what officially are requirements for a "PC"). Is there an official answer to to this ? I am still under the assumption that officially BIOS code is assumed only to be executed under real mode. I can perfectly fine understand that maybe the maority of simple BIOS pieces for "normal" boot hardware may be so "simple" that they even perate under virtual mode, but that isn't a good argument to expect all BIOS code to execute from virtual mode, or is it ? > > Without such a reference i think anybody would have a hard time arguing > > the case of requesting support for virtual mode from the BIOS of some > > HW vendor, right ? > > Basically, the only problems we have with BIOS's usually happen because the > BIOS writer thought they could be cute by entering protected mode themselves > instead of using the defined BIOS calls (such as int 0x15, function 0x87) to > access upper memory, etc. I can believe that. But you also know that most exotic hardware by itself will not officially support FreeBSD even though someone like sos may have written a cool driver for it. ANd if then FreeBSD is the only OS with such requirements against the BIOS of add-on hardware and neither any windows nor Linux has it - that makes FreeBSD painting itself in a corner where boot-compatibility is lower than necessary. No such vendor would change their BIOS for it! Why not rather stick to requirements against the hardware that are known also to be needed by unfortunately better supported OSs ? Why not at least have an option for a boot process that does so ? Eg: I can find a replacement for boot2 easily, but how can i get the kernel nowadays booted without loader in between ? When was actually this btx client concept introduced in FreeBSD ? Eg: wasn't the bootstrap in before the kernel real-mode up until BSD 4.x ? Cheers Toerless