> I'm not sure if this report still applies
> http://osdir.com/ml/file-systems.ntfs.devel/2005-08/msg00224.html
> "BTW2, I'm afraid [lib]parted can still corrupt partition
> tables if the number of heads are 240 (mainly laptops).

When kernel 2.6 was released, it strictly followed the
Extended Interrupt 13h Disk Services specification.  This
includes LBA and other geometry standards, including support
for heads of 255+ (for ATA 48-bit sectors), as well as 16 or
32 (some NAND EEPROM options).

The "240" issue comes from _buggy_ BIOSes, namely those
of IBM-Levono:

  Return 5-bit/16 heads (10000), “lower 3 bits” from
  sectors (63 = 111111) = an erroneous 240 (11110000)
  heads as the 8-bit/0-255 heads value

Since they have left it that way for so long, it's almost
a legacy requirement they "leave it buggy" for
compatibility with their own tools.

> They could perhaps test and definitely keep in mind this
> (the problem manifests only in some rare case)."

The problem is that following the Extended Interrupt 13h
Disk Services specifications is in conflict with much of
this.

Personally, for maximum compatibility across all PC/OSes
(except DOS 7/Win9x, which absolutely requires the BIOS
and disk label/partition table geometry to match), I
first fire off this:  

  # fdisk -H 255 -S 63 /dev/sda

I initialize any new partition table with 255/63.  That
is what Microsoft actually does when it sees geometry issues
as well in NT4SP4+ too, so it's a good one to follow (to
follow their assumptions).  In fact, it's because parted
did not always "look" to check that Windows might have forced
the 255/63 geometry on a "buggy" 240/63 that often caused the
issue.

Unfortunately it's not ideal going forward, although you can
use GPT and other things.

Frankly, the sooner we get to EFI, the better.  Unfortunately
Microsoft keeps dragging their feet on universal support of
EFI, even though Linux has had 32-bit and 64-bit EFI support
for some time (at least Apple uses 32-bit EFI).

The nice thing about fdisk, versus parted, is that it does
_not_ initial any slices/volumes/filesystems.  Parted will
go off and do all sorts of things for you.  So if I don't
like how the geometry ends up, I can always quite without
saving with fdisk.  With parted, by default, it's writing
everytime you change something.

-- Bryan

P.S.  Yes, I'm still around.  ;)


-- 
Bryan J Smith          Professional, Technical Annoyance
[EMAIL PROTECTED]    http://www.linkedin.com/in/bjsmith
--------------------------------------------------------
I don't have a "favorite Linux distro."  I use, develop
and support community efforts, often built around Linux.
Technology and solutions are my focus, not dragging in
assumptions, marketing and other concepts which dominate
non-community developed software, which I left long ago.

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