[Mageia-discuss] partitioning bug

[andre999]

blind Pete a écrit :
> Pascal Terjan wrote:
>
>    
>> On Fri, Jul 6, 2012 at 8:37 AM, blind Pete
>> <0123peter at gmail.com>  wrote:
>>      
>>> David W. Hodgins wrote:
>>>
>>>        
>>>> On Thu, 05 Jul 2012 05:10:30 -0400, blind Pete
>>>> <0123peter at gmail.com>  wrote:
>>>>
>>>>          
>>>>> Cfdisk is very unhappy about something.
>>>>>
>>>>>      FATAL ERROR: Bad primary partition 3: Partition begins after
>>>>>      end-of-disk Press any key to exit cfdisk
>>>>>
>>>>> It looks like cfdisk's error message is wrong.  Partition 3 is mounted
>>>>> and in use.
>>>>>            
>>>>          
>>>>> Disk /dev/sda: 121601 cylinders, 255 heads, 63 sectors/track
>>>>> Warning: extended partition does not start at a cylinder boundary.
>>>>> DOS and Linux will interpret the contents differently.
>>>>> Units = sectors of 512 bytes, counting from 0
>>>>>            
>>>> 121601x255x63=1953520065
>>>>          
>>> CHS has not been reliable since zones were introduced decades ago.
>>> They are just a general hint that it is a big drive.  LBA or
>>> sector number is all that matters.  What happens inside the HDD
>>> case is an unknowable mystery.
>>>        
>> But cfdisk is still based on CHS (or was few years ago).
>>      
> Ancient history:
>
> Before the introduction of the ATA hard drive standard, in about 1990,
> the normal way to address a sector was with a CHS tuple.  With ATA
> zone formatting became standard practice.  There are fewer sectors in
> a cylinder near the spindle than in a cylinder near the rim.  The
> Integrated Drive Electronics then "translated" the hidden real, but
> variable, geometry into a pretend geometry with a constant number of
> sectors per cylinder, so that existing operating systems like DOS and
> possibly BIOSes would not fail miserably by being told that 1,1,20
> does not exist, but 20,1,30 is fine.
>
> Aligning things with physical cylinders was sometimes a good idea, but
> now that information is hidden inside the drive.  Aligning things with
> pretend cylinders is pointless, because they probably don't correspond
> to physical cylinders.
>
>    
>> For example https://bugzilla.redhat.com/show_bug.cgi?id=630340#c1 says
>> that 2.18 (the one in mageia 1) expected the size of the device to be
>> a multiple of the cylinder size.
>>      
> There was a bug in cfdisk two years ago.  It seems to have been fixed.
> Mageia 2's cfdisk does not complain about my hard drive.
>
>    
>>> Even if partition four were past the end of the disk it would not
>>> excuse cfdisk for complaining about partition three.
>>>        
>> Yes I don't know why it complains about 3 and not 4
>>      
> The old version does some invalid maths - and gets the wrong answer.
>    
Just a wild guess, but maybe cfdisk is using base 0 in the error message ?
i.e., starting with "partition 0" for the first partition, and saying 
"partition 3" for the 4th

-- 
André