Date: Sat, 26 Oct 2002 10:06:12 +0100 (BST) From: Mark Valentine <mark@thuvia.demon.co.uk> To: Bruce Evans <bde@zeta.org.au>, Terry Lambert <tlambert2@mindspring.com> Cc: Julian Elischer <julian@elischer.org>, Poul-Henning Kamp <phk@critter.freebsd.dk>, "M. Warner Losh" <imp@bsdimp.com>, <freebsd-arch@FreeBSD.ORG> Subject: Re: cvs commit: src/lib/libdisk Makefile chunk.c write_alpha_disk.c write_i386_disk.c write_pc98_disk.c Message-ID: <200210260906.g9Q96CRx098771@dotar.thuvia.org> In-Reply-To: <20021026095818.B5924-100000@gamplex.bde.org>
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> From: Bruce Evans <bde@zeta.org.au> > Date: Sat 26 Oct, 2002 > Subject: Re: cvs commit: src/lib/libdisk Makefile chunk.c write_alpha_disk.c write_i386_disk.c write_pc98_disk.c > > > Because DOS doesn't refer to its partition by its index in the MBR partition > > > table, and apparently some tools therefore feel free to reorder the table on > > > a whim. > > This is a bug in the tools, so they belong in the same bin as BIOSes that > interpret the MBR. That's reassuring to know... (The behaviour seems evil to me, but I haven't seen anything so far which explicitly forbids it, and of course It Happens.) I'm less inclined to worry about workarounds for buggy tools, but I still feel there's a flaw here. By the way, FreeBSD doesn't seem to be consistent about which partition it uses, but I've never tried to figure out when it uses partition 1 and when it uses partition 4, though I've seen both occur on disks with only FreeBSD (is it DD mode that makes the difference?). > > OK, say we buy this. > > > > How does the DOS algorithm distiguisch between partitions, if not by > > the order in the table? > > Not. IIRC, it doesn't permit multiple primary DOS partitions, but logical > drives just move around if you add one in the middle. Indeed, you lose if you try to use this with multiple 0xA5 partitions without making one and only one of them "active" (or does that even make a difference?). That's DOS-compatible. Cheers, Mark. -- Mark Valentine, Thuvia Labs <mark@thuvia.co.uk> <http://www.thuvia.co.uk>; "Tigers will do ANYTHING for a tuna fish sandwich." Mark Valentine uses "We're kind of stupid that way." *munch* *munch* and endorses FreeBSD -- <http://www.calvinandhobbes.com>; <http://www.freebsd.org>; To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message
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