[RndTbl] drive partitioning for Linux install
athompso at athompso.net
Thu Sep 29 22:21:01 CDT 2005
Dan Martin wrote:
> The error indicates inconsistency between how DOS reads the partition
> info and how other OSs (including Windows) reads it - the result is 2
> different hard drive geometries being reported. I don't know how to
> fix this - I would have thought creating the partitions under DOS in
> PM7 in the first place would solve the problem - but it has still
> retained an alternate description of drive geometry. I can create 3
> primary partitions without a problem, but if I add an extended
> partition that takes up the rest of the drive, I get the error.
> Does the "c" command in Linux fdisk have anything to do with this? I
> can't see that it actually does anything.
Short answer: turn on LBA support in your BIOS. Don't use 'auto' or
'large drive support', if you can avoid it, and especially avoid 'chs'
That may not be sufficient, it depends on what version of DOS you're
Unfortunately, if you turn on LBA (or LBA32) mode, your partition table
will be scrambled... but even worse, if you boot from DOS it will still
read sector 0 from the drive and infer geometry from what it finds
there, not from the BIOS. The easiest way around this is to turn on
LBA, then immediately install Windows 2000 or Windows XP or Linux.
Don't even try booting DOS until you've successfully recreated the
partition table under a more advanced OS. Do NOT try "fixing" things
with PartitionMagic at this point, it will just make a worse mess.
(If you boot a Linux kernel, during the boot sequence it identified the
disks it found. Output from 'dmesg' should indicate "hda: ....." and it
should show some sort of indication as to whether the disk geometry is
in C/H/S mode or LBA mode.)
You might want to read the Large Disk HOWTO, found at:
http://www.tldp.org/HOWTO/Large-Disk-HOWTO.html as it discusses the sort
of thing that I think you're running into.
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