OT: corrupted FATs on an external drive

[Mikkel L. Ellertson]

peter kostov wrote:
> Mikkel L. Ellertson wrote:
>> peter kostov wrote:
>>  
>>> Hi,
>>>
>>> I have a Samsung mp3 player that doesn't want to format his drive.
>>> When I run fsck on it I get:
>>>
>>> # fsck.vfat -rtlV -v /dev/sdb1
>>> dosfsck 2.11 (12 Mar 2005)
>>> dosfsck 2.11, 12 Mar 2005, FAT32, LFN
>>> Checking we can access the last sector of the filesystem
>>> Boot sector contents:
>>> System ID "MSDOS5.0"
>>>     
>> <-----------------[ snip ]----------------->
>>  
>>> I have tried mkdosfs with no luck.
>>> I will appreciate very much if anyone can tell mi what to do to get it
>>> back to work.
>>>
>>> Peter
>>>
>>>     
>> What kind of error did you get with mkdosfs? Did you remember to
>> specify that you wanted a FAT32 file system? (-F 32).
>>
>> Mikkel
>>   
> Thanks Mikkel, but there wasn't an error. There wasn't any effect also.
> I have tried several times with -F 16, because fsck reported:
> First FAT starts at byte 512 (sector 1)
>        2 FATs, 16 bit entries
> Then I have tried with -F 32, again with no success. As I sad mkdosfs
> didn't report any error, however in dmesg I saw several resets of the
> device during the mkdosfs process. After that when I remount the player
> all the files are still there, and the player itself again doesn't see
> them.
> Peter
> 
It almost looks like the device is write-protecting its file system.
But it could be from other causes. A couple of things to keep in
mind. You should not run mkdosfs with the drive mounted. From the
dosfsck output, the system thinks it is a FAT32 file system. You may
want to run "fdisk -l /dev/sdb" to double check the partition type.

Dumb question - are you running mkdosfs on /dev/sdb1, and not
/dev/sdb? Running it on /dev/sdb will produce strange results,
including possible corruption of files on the device, possibly
without messing up the directories...

Mikkel
-- 

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