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Re: Deletion of files from usb-key

Haines Brown wrote:
I have a SamDisk USB-key filled with photos (.png) which I used for a slide show. I now would like to delete them, but whenever the device 
is rebooted, the files reappear.

	$ ls -la /media/usb-key
	rwxr-xr-x  file.png /brownh/brownh
Post the actual output of 'ls -la'. Also the output of 'df /media/usb-key' with the device mounted would help 

<snip>

In desperation I try:

	$ shred -fuv /media/usb-key *.*
	shred: /media/usb-key/<filename>: pass 1/25 (random)...
shred: /media/usb-key/<filename> : fdatasync failed: Input/output error 
	shred: /media/usb-key/<filename>: pass 2/25 (888888)...
shred: /media/usb-key/<filename>: fdatasync failed: Input/output error 
	...
Hmmm... appears to be some hardware error or a case of filesystem corruption. Did you try dosfsck on the drive?
and also tried: 
	# mformat -v /dev/sdd1
Use mkdosfs. Unless you assigned a drive letter to your flash drive, mformat is unlikely to work.
It failed to run, perhaps because the usb-key has no unix low-level 

In that case please post the error messages.


format. And I also tried:
# fdisk /dev/sdd1 

It should be /dev/sdd. Not sdd1



I print the partition table:

	Disk /dev/sdd1: 512 MB, 512443392 bytes
	16 heads, 62 sectors/track, 1008 cylinders
	Units = cylinders of 992 * 512 = 507904 bytes

	     Device Boot      Start         End      Blocks   Id  System

This suggests there is no partition at present. So I add a partition
(primary, number 1, cylinders 1-1088. Now I print this and have:

	Disk /dev/sdd1: 512 MB, 512443392 bytes
	16 heads, 62 sectors/track, 1008 cylinders
	Units = cylinders of 992 * 512 = 507904 bytes

	     Device Boot      Start         End      Blocks   Id  System
	/dev/sdd1p1               1        1008      499937   83  Linux

And I change the type to 4 and print again:

	Disk /dev/sdd1: 512 MB, 512443392 bytes
	16 heads, 62 sectors/track, 1008 cylinders
	Units = cylinders of 992 * 512 = 507904 bytes

        Device Boot   Start     End   Blocks   Id  System
	/dev/sdd1p1       1    1008   499937    4  FAT16 <32M

And write and quit (w command):

	The partition table has been altered!

	Calling ioctl() to re-read partition table.
WARNING: Re-reading the partition table failed with error 22: Invalid argument. 
	The kernel still uses the old table.
	The new table will be used at the next reboot.

	WARNING: If you have created or modified any DOS 6.x
	partitions, please see the fdisk manual page for additional
	information.
	Syncing disks.
Well, I tried: 
        # sfdisk /dev/sdd1
        Checking that no-one is using this disk right now ...
        BLKRRPART: Invalid argument
        OK
        Warning: start=62 - this looks like a partition rather than
        the entire disk. Using fdisk on it is probably meaningless.
        [Use the --force option if you really want this]
When I use sfdisk with --force option, 
        ...
        Disk /dev/sdd1: 1008 cylinders, 16 heads, 62 sectors/track
        Old situation:
        Units = cylinders of 507904 bytes, blocks of 1024 bytes,
counting from 0 
           Device Boot Start     End   #cyls    #blocks   Id  System
        /dev/sdd1p1          0       -       0          0    0  Empty
        /dev/sdd1p2          0       -       0          0    0  Empty
        /dev/sdd1p3          0       -       0          0    0  Empty
        /dev/sdd1p4          0       -       0          0    0  Empty

        /dev/sdd1p1 :

Next I try:
# mkfs.vfat -F 32 /dev/sdd1 mkfs.vfat 2.11 (12 Mar 2005) 

But my files still there. Fsck didn't help.

My guess is that I need a low level format, but I have no idea how to
do that for a usb-key. Is it usually done with a proprietary low-level
format utility?
Just try the following, assuming your usb key is at /dev/sdd (change if it isn't) 

1. dd if=/dev/zero of=/dev/sdd bs=512 count=1
2. mkdosfs -I -v /dev/sdd

Now you should be able to mount /dev/sdd.


--
Raj Kiran Grandhi
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