Re: Differences in Primary GPT Header

[Tobias Arp]

-----Ursprüngliche Nachricht-----
Von: Jim Meyering <address@hidden>
Gesendet: 18.02.2010 09:31:54
An: Tobias Arp <address@hidden>
Betreff: Re: Differences in Primary GPT Header

>Tobias Arp wrote:
>> i am using parted  2.1 aand i have some questions about gpt partitions.
>> I have created a gpt partion on a harddisk. After creating a ntfs file 
>> system on this partition i got full access to this drive.
>> I could read and write successfully on it.
>> I viewed the primary gpt header on my linux computer and printed it.
>> Then i put this harddisk on my windows 7 pc. The harddisk is detected 
>> successfully and i can access all files.
>> But  after having the drive in my windows computer changes are made to the 
>> primary gpt header.
>>
>> Following values aree changed:
>>
>> Offset 0x20 = Backup LBA
>> Offset 0x30 = Last usable LBA
>>
>> Both are decreased for about 30 sectors.
>> Windows does it.
>
>Thanks for the report.
>
>> When i look into the documentation of gpt partitions it seems to be right 
>> what windows has done.
>
>Why?
>

I think Offset 0x30 (Last usable LBA) should be the LBA before the Backup 
Partition Array and not the Last LBA of the Harddisk.
Or is this wrong?

>Please provide more information, e.g., the output of this:
>(assuming your disk is /dev/sda)
>
>    # parted -s /dev/sda u s print free

Model: ATA LaCie Biggest Qu (scsi)
Disk /dev/sdb: 11721081216s
Sector size (logical/physical): 512B/512B
Partition Table: gpt

Number  Start  End           Size          File system  Name                  
Flags
 1      34s    11721081182s  11721081149s  ntfs         Basic data partition


>
>That will tell us the size in sectors of your disk.
>
>Then tell us the actual values from your primary table by running this:
>(again, assuming /dev/sda)
>
>    # od -w8 -Ad --skip=$((512+32)) -N24 -td8 /dev/sda

0000544          11721081215
0000552                   34
0000560          11721081182
0000568

Wje i look into the disk with a disk editor on windows 7 the last 
usable sector is 11721081152...

Hope that helps.


Regards

Tobias
___________________________________________________________
GRATIS für alle WEB.DE-Nutzer: Die maxdome Movie-FLAT!
Jetzt freischalten unter http://movieflat.web.de