Date: Sun, 09 Dec 2001 22:44:52 -0800 From: Peter Wemm <peter@wemm.org> To: "David W. Chapman Jr." <dwcjr@inethouston.net> Cc: current@FreeBSD.ORG Subject: Re: "Dangerously dedicated" yet again (was: cvs commit: src/sys/kern subr_diskmbr.c) Message-ID: <20011210064452.739173810@overcee.netplex.com.au> In-Reply-To: <20011210051454.GA49775@leviathan.inethouston.net>
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"David W. Chapman Jr." wrote: > On Sun, Dec 09, 2001 at 06:46:24PM -0800, Terry Lambert wrote: > > It's because you have to reinstall, should you want to add a second > > OS at a later date (e.g. Linux, or Windows). > > I think it has more to do with the drive going on a new motherboard > that might not boot with dangerously dedicated than the above. .. And the mere presence of one of the disks that causes the bios to lock up at boot. Note that this is a particularly bad thing in laptops. There are three classes of behavior: 1) You luck out and it works 2) You get a bios divide-by-zero fault when you *boot* of the disk. This shows up as a 'BTX fault'. If you check the lists, a good number of btx faults posted to the lists have int=0 (divide by zero) in them. The problem is more widespread than it appears. 3) You get a system lockup when booting the *computer* if *any* DD disk is attached anywhere at all. This is what killed the Thinkpad T20*, A20*, 600X etc. After all the yelling we did at IBM, it turned out to be FreeBSD's fault. It also happens on Dell systems. It kills all IA64 boxes if a FreeBSD/i386 disk is attached anywhere. An additional problem is that because boot1 has got a fdisk table embedded in it unconditionally, a freebsd partition *looks* like it has got a recursive MBR in it. This is what is really bad and is what is killing us on newer systems. What really sucks is that there is **NO WAY** to remove it with the tools that we have except a hex editor. Cheers, -Peter -- Peter Wemm - peter@FreeBSD.org; peter@yahoo-inc.com; peter@netplex.com.au "All of this is for nothing if we don't go to the stars" - JMS/B5 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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