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Auteur: Fred
Date:  
À: ael
CC: dng
Sujet: Re: [DNG] fdisk SD card partitioning question
On 6/12/22 13:48, ael wrote:
> On Sun, Jun 12, 2022 at 12:35:06PM -0700, Fred wrote:
>> On 6/12/22 09:18, Antony Stone wrote:
>>> On Sunday 12 June 2022 at 17:11:45, Fred wrote:
>>>
>>>> Hello,
>>>>
>>>> I have some directories I want to back up to an SD card while preserving
>>>> the permissions. I have tried to repartition a 64GB card and write an
>>>> ext4 filesystem.
>>>
>>> What is the existing partition table?
>>>
>>> Out of interest, since this is ext4 and therefore Linux (not Windows), why
>>> partiton at all? Why not just "mkfs.ext4 /dev/sdX"?
>>>
>>>> fdisk says the card has 124702720 sectors and has 59.5GB available.
>>>> However it will not make a partition over 27.5GB. Why and what to do?
>
> Are you sure that this is not just another example of "Flash Fraud"?
> You could try running https://github.com/AltraMayor/f3 .
>
>
>> Hi,
>> As supplied the SD cards are intended to work with Windows. Under Linux
>> only root can write to them and the ownership can not be changed. I want
>> preserve permissions of data written to the card.
>
> I don't follow above. SD cards usually come with a vfat file system and
> are indeed set up mainly for Windoze. But if you mount with
> -o uid=someone,gid=someone,..
> then that someone user can write.
>
> I do this all the time with a whole variety of sdhc cards. I only leave
> them formated for vfat if I need to move them between other devices
> (cameras, sat navs, ereaders which only read and write vfat). Otherwise
> I use a better file system.
>
>>
>> root@aragog:# /sbin/fdisk -l /dev/sdb
>> Disk /dev/sdb: 27.48 GiB, 29504831488 bytes, 57626624 sectors
>> Disk model: Card-Reader
>> Units: sectors of 1 * 512 = 512 bytes
>> Sector size (logical/physical): 512 bytes / 512 bytes
>> I/O size (minimum/optimal): 512 bytes / 512 bytes
>> Disklabel type: dos
>> Disk identifier: 0x00000000
>>
>> Device     Boot Start       End   Sectors  Size Id Type
>> /dev/sdb1       32768 124735487 124702720 59.5G  7 HPFS/NTFS/exFAT

>>
>> I don't know why the size is reported differently in two places. It is a
>> 64GB card.
>
> Are you sure?? Not a faked 32GB ?
>
>>
>> I tried your dd command line and things have gone downhill as the 64GB card
>> is now only 27.4GB.
>
> So almost certainly a fake. Did you but this from somewhere trustworthy?
>
>> root@aragog:# /sbin/fdisk -l /dev/sdb
>> Disk /dev/sdb: 27.48 GiB, 29504831488 bytes, 57626624 sectors
>> Disk model: Card-Reader
>> Units: sectors of 1 * 512 = 512 bytes
>> Sector size (logical/physical): 512 bytes / 512 bytes
>> I/O size (minimum/optimal): 512 bytes / 512 bytes
>>
>>
>> I tried fdisk again with the same result.
>>
>> root@aragog:# /sbin/fdisk /dev/sdb
>> Command (m for help): n
>> Partition type
>>     p   primary (0 primary, 0 extended, 4 free)
>>     e   extended (container for logical partitions)
>> Select (default p): p
>> Partition number (1-4, default 1): 1
>> First sector (2048-57626623, default 2048):
>> Last sector, +/-sectors or +/-size{K,M,G,T,P} (2048-57626623, default
>> 57626623):

>>
>> Created a new partition 1 of type 'Linux' and of size 27.5 GiB.
>>
>> Command (m for help): d
>> Selected partition 1
>> Partition 1 has been deleted.
>>
>> Command (m for help): n
>> Partition type
>>     p   primary (0 primary, 0 extended, 4 free)
>>     e   extended (container for logical partitions)
>> Select (default p): e
>> Partition number (1-4, default 1): 1
>> First sector (2048-57626623, default 2048):
>> Last sector, +/-sectors or +/-size{K,M,G,T,P} (2048-57626623, default
>> 57626623):

>>
>> Created a new partition 1 of type 'Extended' and of size 27.5 GiB.
>>
>>
>> Any ideas?
>
> Yes. Almost certainly a fake....
>
> ael
>

Hi,
I recall a lot of discussion about this on either this list or the
Debian list. If the card was an offbrand I would assume it was fraud
and would not have even asked here. However, the card is a SanDisk.
The packaging becomes destroyed in removing the card so I can't take it
back to Walfart for exchange.

I would like to try the f3 program. How do I get the tarball from github?

You said above that you use a better filesystem for the sdhc cards.
Have you done that for a card over 32GB? And how?

Best regards,
Fred