Date: Mon, 23 Aug 1999 13:29:50 -0600 From: Warner Losh <imp@village.org> To: Bruce Evans <bde@zeta.org.au> Cc: phk@critter.freebsd.dk, cvs-all@FreeBSD.org, cvs-committers@FreeBSD.org Subject: Re: cvs commit: src/sbin/i386/fdisk fdisk.8 fdisk.c Message-ID: <199908231929.NAA40976@harmony.village.org> In-Reply-To: Your message of "Tue, 24 Aug 1999 04:45:21 %2B1000." <199908231845.EAA01679@godzilla.zeta.org.au> References: <199908231845.EAA01679@godzilla.zeta.org.au>
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In message <199908231845.EAA01679@godzilla.zeta.org.au> Bruce Evans writes: : SCSI disks and controllers don't "use" any geometry. They do in the boot process. The Int13 interface of the BIOS of the UltraStor 34F controller tries to get at blocks from a head/sector/track and if those are messed up somehow, things can get confusing... It is the only place where it matters, however. Everything else just works... When there is a mismatch, I've had an unbootable system. I think this has something to do with the fact that if you don't have the geometry that you think you have the UltraStor's BIOS will map the requested block in a way that is different than boot blocks think... And at one time (and I don't know if this is still true or not) FreeBSD's fdisk or sysinstall program tried to cope with this by setting sectors to a huge number... : IIRC, the U34F normally reports a geometry of 64 tracks and 32 sectors, : and isn't very flexible (I vaguely remember a 128 track mode). This works : OK for those huge 600 MB drives that we had a few years ago when U34Fs : were almost worth using, but runs into 1024-cylinder problems for >= 1GB : drives. 63 tracks, but you are essentially correct. Warner To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message
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