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Date: Wed, 02 May 2012 20:49:25 +0200
From: Christian Borntraeger <borntraeger@de.ibm.com>
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Subject: Re: [Qemu-devel] [PATCH 2/3] geometry detection: use HDIO_GETGEO
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To: Alexander Graf <agraf@suse.de>
Cc: Heinz Graalfs <graalfs@linux.vnet.ibm.com>, qemu-devel <qemu-devel@nongnu.org>, Jens Freimann <jfrei@linux.vnet.ibm.com>, Cornelia Huck <cornelia.huck@de.ibm.com>, Paolo Bonzini <pbonzini@redhat.com>, Stefan Weinhuber <wein@linux.vnet.ibm.com>, Einar Lueck <elelueck@de.ibm.com>

>>> Well, if guessing is a function
>>>
>>>  guess_size(disk_size, block_size)
>>>
>>> then we would be able to do the same on an image file. Christian, would that work?
>>
>> I think that the geometry values can not always be guessed correctly based on
>> block_size and disk_size.
>>
>> Stefan, can you clarify that?
>>
>> If we cannot reliably guess the geometry based on blocksize and size, I still think
>> that we should use the host values, e.g. after checking that BIODASDINFO2 returns 
>> successfully.
> 
> Yeah, but only if it's always possible to force a specific geometry through the command line - otherwise reproducability suffers.

That is already possible, with the exception of the sector part of the geometry (see the other
patch :-) )

Christian