Date: Sat, 02 Jan 2010 14:28:50 -0800 From: Julian Elischer <julian@elischer.org> To: Poul-Henning Kamp <phk@phk.freebsd.dk> Cc: =?ISO-8859-1?Q?Ulrich_Sp=F6rlein?= <uqs@spoerlein.net>, Miroslav Lachman <000.fbsd@quip.cz>, Thomas Backman <serenity@exscape.org>, freebsd-current@freebsd.org, freebsd-arch@freebsd.org, Pieter de Goeje <pieter@degoeje.nl>, Alexander Motin <mav@freebsd.org> Subject: Re: File system blocks alignment Message-ID: <4B3FC8A2.1090901@elischer.org> In-Reply-To: <67020.1262425354@critter.freebsd.dk> References: <67020.1262425354@critter.freebsd.dk>
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Poul-Henning Kamp wrote: > In message <20100102050843.GI3508@acme.spoerlein.net>, Ulrich =?utf-8?B?U3DDtnJ > sZWlu?= writes: > >> Sysinstall, fdisk, gpart >> and bsdlabel should all display some fat warning if partition/label >> alignment is not, say at 256kB (a common stripe size, right?) > > You overlook that MBR/Fdisk requires bootable slices to start at a > "track". That means that the propper slice-alignmen typically > will be 8*63=504 sectors. No it doesn't, (or at least it didn't) but it has become custom to do so. You could always put your slice anywhere (within the stupid geometry constraints) but the ENDING cylinder/head/block numbers were taken to be at the END of a cylinder when there were no other ways of working out the geometry, so that you could "infer" the geometry. packet enabled BIOS's made it all go away. It was all forced on us by IBM. > > Unless you want to explore how many BIOS'es still are stupid about > this... >
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