Date: Fri, 23 Jan 2004 17:56:15 +1030 From: "W. Sierke" <ws+freebsd-questions@au.dyndns.ws> To: "Keith Kelly" <c0d3h4x0r@hotmail.com>, "Charles Swiger" <cswiger@mac.com> Cc: freebsd-questions <freebsd-questions@freebsd.org> Subject: Re: FDisk won't detect or accept correct disk geometry from BIOS Message-ID: <020f01c3e182$34a78de0$8464a8c0@ovirt.dyndns.ws> References: <200401222044.i0MKi5a27869@clunix.cl.msu.edu><Sea1-DAV33jrntuajNS0002a5c9@hotmail.com><2BB15265-4D2E-11D8-95B0-003065A20588@mac.com> <Sea1-DAV42g9zflSBSn0003039c@hotmail.com>
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"Keith Kelly" wrote: > > On Jan 22, 2004, at 5:24 PM, Keith Kelly wrote: > > > I already tried (with both 4.9 and 5.1) letting the FreeBSD install > > > proceed > > > with fdisk's geometry value assumptions, and what I always get is a > > > non-bootable hard drive that gives the "Missing operating system" > > > error at > > > boot. > > > > Sufficiently old motherboards and BIOS versions don't understand the > > LBA addressing mode used by modern drives, and are limited to seeing > > approx 8.4 GB using the classic C/H/S values. See whether the BIOS > > lets you configure the drive to LBA mode rather than "automatic", > > "C/H/S", or "extended C/H/S" mode. If it doesn't, check to see whether > > there is a BIOS update available for your hardware. > > The motherboard is not old. It is an MSI KT4 Ultra motherboard, if I > remember the model number correctly off the top of my head, for the Athlon > XP architecture. The BIOS doesn't even explicitly list what mode (LBA, CHS, > extended CHS) it is using to address the drive -- I just set it to "Auto", > it detects the device name, and fills out a small listing telling me the > C/H/S geometry it is using. The motherboard is already running the latest > available BIOS update from MSI. From: "Christopher Turner" <christopher@contemplation.org> > I have two 40Gig Seagate Baracuda IV's. > > The physical drive is 1023/256/63 > The BIOS detects it at 1024/255/63 I have an 80G Seagate (ST380024A) attached to an old MB (pentium socket 7(?)) with an AMI BIOS. Seagate specify the logical geometry (for Barracuda ATA V drives) as 16383/16/63. This is also what the BIOS auto-detects the drive as. (Note this corresponds to only 8G.) I used this as the BIOS setting to install FreeBSD. However, FreeBSD (4.8) wouldn't boot from the drive until I dropped the BIOS heads setting down (to 16383/15/63). FreeBSD happily ignored this setting change which was done after FreeBSD had been installed. I had assumed that this was a bug in the BIOS. I wonder now whether there is some quirk in FreeBSD's boot managers/loaders that is affected by BIOS settings (perhaps with specific BIOSes)? The AMI BIOS has LBA, Block mode and 32-bit mode settings enabled. To further add to the curiosity, fdisk reports the drive as 9729/255/63 (which is 5103 sectors short of the drive's full capacity). dmesg.boot, however, shows: ad0: 76319MB <ST380024A> [155061/16/63] at ata0-master WDMA2 which corresponds to the drive's full capacity. Wayne
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