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Re: mounting usb frustration

Haines Brown wrote:

I mounted a USB flash card with a reader OK once, but failed the
second time. With two hard disks, an external USB mass storage deveice
and with a USB-key, all mounted using sda-sdd interfaces, # mount -t vfat /dev/sde1 /media/reader mount: special device /dev/sde1 does not exist 

Indeed, udev has not generated any such interface. I have sdc, sdc1,
sdd, sdd1, sde, sdf, sdf1. The sda and sdb interfaces are for hard
disks. 
The flash card reader is seen on the USB bus and the necessary modules
are loaded.

But I get a very odd report from trying to mount sde1: :

  $ dmesg | tail
  sdf: assuming drive cache: write through
  SCSI device sdf: 234441648 512-byte hdwr sectors (120034 MB)
  sdf: Write Protect is off
  sdf: Mode Sense: 27 00 00 00
  sdf: assuming drive cache: write through sdf: sdf1
  sd 13:0:0:0: Attached scsi disk sdf
  usb-storage: device scan complete
  FAT: bogus number of reserved sectors
  VFS: Can't find a valid FAT filesystem on dev sdb1.

The message about FAT on sdb1 is correct, for it is ext2. Since udev
had created a sdf1, if I try to mount using it: # mount -t vfat /dev/sdf1 /media/reader mount: wrong fs type, bad option, bad superblock on /dev/sdf1, 
       missing codepage or other error
       In some cases useful info is found in syslog - try
       dmesg | tail  or so

I get the sense that for some reason udev is not creating sde1, and so
sdf and sdf1 are created, but can't be used. I'm running Etch, and
udev is 0.105-4.
I've seen this sort of thing happen, when the system, for whatever reason, thinks the original device is still attached. The detection event for the second use is then given a new device node.
You may want to try running an 'fdisk' on the device names, to see which actually has partitions, and what their type(s) is(are). For example: 

# fdisk -l /dev/sde

Disk /dev/sde: 65 MB, 65012224 bytes
8 heads, 32 sectors/track, 496 cylinders
Units = cylinders of 256 * 512 = 131072 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sde1   *           1         484       61924+   1  FAT12
Partition 1 has different physical/logical endings:
     phys=(499, 7, 32) logical=(483, 7, 32)
which will at least tell you the device name to use with the mount command, and the file system type. 

--
Bob McGowan

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