Date: Fri, 1 Feb 2002 01:18:13 +0100 From: Erik Trulsson <ertr1013@student.uu.se> To: FreeBSD Stable <fbsdstable@cobble.capnet.state.tx.us> Cc: freebsd-stable@freebsd.org Subject: Re: Setting drive geometry, big drives? Message-ID: <20020201001811.GA2579@student.uu.se> In-Reply-To: <20020131163919.A96561-100000@cobble.capnet.state.tx.us> References: <20020131163919.A96561-100000@cobble.capnet.state.tx.us>
next in thread | previous in thread | raw e-mail | index | archive | help
On Thu, Jan 31, 2002 at 05:51:11PM -0600, FreeBSD Stable wrote: > [I sent a similar message a few days ago, but that message > apparently got drowned in a flood of messages on another topic.] > > I have an IBM Deskstar 60GB that the BIOS reports as 29437/16/255. > The startup probe reports 119150/16/63. When I try to configure > the drive, I get a message saying 119150/16/63 is incorrect, and > that I need to set it to the BIOS numbers. If I set it to the > BIOS numbers, it still complains that it is incorrect. There is > a message in there warning me not to set the drive to its physical > geometry, though the BIOS 29437/16/255 seems a likely physical > geometry. > > So the partition editor picks another default, which is > 7476/255/63. Which seems to work fine, but now I have three > different numbers. The boot still shows 119150/16/63, the BIOS > still shows 29437/16/255, and the disklabel shows 7476/255/63. I can almost guarantee that none of those numbers are anything even close to the actual physical geometry of the disk. The numbers reported are just a convenient fiction to fit the actual geometry into the restrictions of the BIOS interface. (For example, very few disk today have more than 4 heads and most have only 2. (Unlike the 16/255 heads the numbers above indicate.)) > > Questions: Why the warning about not using the PHYSICAL GEOMETRY, > especially since the BIOS reports an apparently-proper physical > geometry, and I'm told I must use the BIOS settings for the > drive's geometry? And why is the boot message still reporting > 119150/16/63, when that isn't set anywhere??? It is useful to have all OSs on the machine and the BIOS use the same geometry. Otherwise there might be differing opinions of where on the disk partitions/slices start/end. If the settings you have now work, then my advice is to keep using them and not worry about it. (You might check if your BIOS have a setting to choose between LBA and CHS access to the disk. (LBA = Logical Block Addressing, CHS = Cylinders, Heads, Sectors) If it does you might try switching between those and see if it helps.) (After thinking about it a bit more I think what is actually happening is that 119150/16/63 is what the drive reports but since this does not map well into the calling conventions both the OS and the BIOS tries to translate it into something else.) -- <Insert your favourite quote here.> Erik Trulsson ertr1013@student.uu.se To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20020201001811.GA2579>