Re: a (late) question concerning the CHS disaster ...

[Patrick J. LoPresti]

Sven Luther <address@hidden> writes:

> Well, when we use blank disks, there is no problem, because windows
> is not installed on it, right ? And if windows then fail, it is
> windows fault.

If you later install Windows, you will encounter problems.  This is
why I took an interest in this stuff in the first place (see
http://unattended.sourceforge.net/).

> As for machines where disk has been moved, i don't get it. the
> partition table is on disk, so using it is always ok, even if the
> disk was moved.

  1) Move disk between machines

  2) parted /dev/hda

  3) mklabel msdos

  4) mkpart ...

What geometry will/should Parted use?

> > To my knowledge, there is still no way for me to tell Parted what
> > geometry to use.  Which is frustrating, because I (or rather, my code)
> > actually knows.
> 
> Well, you can simply open the device and overwrite bios_geometry,
> not ?

My code is in Perl, invoking the parted binary with the "-s" switch.
I read /sys/firmware/edd/int13_dev80/legacy_* to figure out the
geometry to use.  I write to /proc/ide/hda/settings to convince the
kernel to return that geometry for HDIO_GETGEO.  I wipe the partition
table in a separate step so that Parted will actually use that
geometry instead of guessing.

And it works.  But it is so messy...  And the Linux folks are
threatening to remove HDIO_GETGEO.

 - Pat