Date: Thu, 18 Apr 1996 10:26:25 +1000 From: Bruce Evans <bde@zeta.org.au> To: hackers@FreeBSD.org, mrcpu@cdsnet.net Subject: Re: Putting a valid partition table on a BIG disk? Message-ID: <199604180026.KAA19908@godzilla.zeta.org.au>
next in thread | raw e-mail | index | archive | help
>I have a RAID array that was griping about the slice size not matching the
>partition size. So I reformatted the whole thing, zero'd out the
>disklabels, and am trying to fdisk it somehow.
>Nothing seems to work. THe partition is 16GB.
>DOS fdisk barfs at 8GB. fdisk in /stand gets the correct geometry, but
>then won't accept a number larger than 944 for the ending cylinder, but it
>will let the size by the full 16GB's. /stand/sysinstall causes a panic
>instantly, although I'm in the middle of a make world which may correct
>that.
Use something like the following with /sbin/fdisk:
1) Determine a geometry. For good SCSI BIOSes, by the definition of
`good', you can invent any geometry subject to the DOS limits:
1 <= sectors per track <= 63
1 <= heads <= 255.
and the BIOS will use the same geometry on the next reboot after
the partition table has been written to (provided of course the
entries in the partition table are consistent with a unique
geometry). 63 heads and 255 sectors per track is best if it works.
2) Enter the geometry.
3) Calculate offsets and sizes for a division of the disk into partitions
containing full cylinders. Don't put any bootable or DOS partitions
above cylinder 1023.
4) Adjust the offset and size of the first partition to skip the first
track.
5) Optionally adjust the size of the last partition to contain the sectors
beyond the last full cylinder. If there is only one partition then
this step will cause various entities to be confused about the geometry.
6) Enter the offsets and sizes. Accept the defaults for everything else.
7) Write the partition table.
>Well anyway, I got a disklabel on there with disklabel, but everytime the
>raw device is opened, I get the error about an invalid partition table.
Write bytes 55, AA at the end of the first sector of the disk using a
binary editor, or put a bootstrap on the disk using disklabel -B.
Bruce
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199604180026.KAA19908>