I just can't use my USB disk now.when pluged in,the disk can't be mounted and the "dmesg" output is as following:
[17186166.044000] usb 2-1: new full speed USB device using uhci_hcd and address 2
[17186167.200000] SCSI subsystem initialized
[17186167.300000] Initializing USB Mass Storage driver...
[17186167.300000] scsi0 : SCSI emulation for USB Mass Storage devices
[17186167.300000] usb-storage: device found at 2
[17186167.300000] usb-storage: waiting for device to settle before scanning
[17186167.300000] usbcore: registered new driver usb-storage
[17186167.300000] USB Mass Storage support registered.
[17186172.304000] Vendor: USB Model: Flash Disk Rev: 2.00
[17186172.304000] Type: Direct-Access ANSI SCSI revision: 02
[17186172.312000] usb-storage: device scan complete
[17186172.408000] Driver 'sd' needs updating - please use bus_type methods
[17186172.416000] SCSI device sda: 509696 512-byte hdwr sectors (261 MB)
[17186172.416000] sda: assuming drive cache: write through
[17186172.420000] SCSI device sda: 509696 512-byte hdwr sectors (261 MB)
[17186172.420000] sda: assuming drive cache: write through
[17186172.420000] sda: sda1
[17186172.428000] sd 0:0:0:0: Attached scsi disk sda
[17186172.596000] sd 0:0:0:0: Attached scsi generic sg0 type 0
[17186174.992000] FAT: utf8 is not a recommended IO charset for FAT filesystems, filesystem will be case sensitive!
[17186250.232000] usb 2-1: USB disconnect, address 2
[17186672.184000] usb 2-2: new full speed USB device using uhci_hcd and address 3
[17186672.320000] scsi1 : SCSI emulation for USB Mass Storage devices
[17186672.320000] usb-storage: device found at 3
[17186672.320000] usb-storage: waiting for device to settle before scanning
[17186677.324000] Vendor: USB Model: Flash Disk Rev: 2.00
[17186677.324000] Type: Direct-Access ANSI SCSI revision: 02
[17186677.328000] SCSI device sda: 509696 512-byte hdwr sectors (261 MB)
[17186677.328000] sda: assuming drive cache: write through
[17186677.332000] SCSI device sda: 509696 512-byte hdwr sectors (261 MB)
[17186677.332000] sda: assuming drive cache: write through
[17186677.332000] sda: sda1
[17186677.340000] sd 1:0:0:0: Attached scsi disk sda
[17186677.340000] sd 1:0:0:0: Attached scsi generic sg0 type 0
[17186677.340000] usb-storage: device scan complete
[17186678.796000] FAT: utf8 is not a recommended IO charset for FAT filesystems, filesystem will be case sensitive!
[17186740.992000] usb 2-2: USB disconnect, address 3
[17191738.652000] usb 2-1: new full speed USB device using uhci_hcd and address 4
[17191738.772000] usb 2-1: device descriptor read/64, error -71
[17191738.996000] usb 2-1: device descriptor read/64, error -71
[17191739.212000] usb 2-1: new full speed USB device using uhci_hcd and address 5
[17191739.332000] usb 2-1: device descriptor read/64, error -71
[17191739.556000] usb 2-1: device descriptor read/64, error -71
[17191739.772000] usb 2-1: new full speed USB device using uhci_hcd and address 6
[17191740.180000] usb 2-1: device not accepting address 6, error -71
[17191740.292000] usb 2-1: new full speed USB device using uhci_hcd and address 7
[17191740.700000] usb 2-1: device not accepting address 7, error -71
[17192538.152000] usb 2-1: new full speed USB device using uhci_hcd and address 8
[17192538.272000] usb 2-1: device descriptor read/64, error -71
[17192538.496000] usb 2-1: device descriptor read/64, error -71
[17192538.712000] usb 2-1: new full speed USB device using uhci_hcd and address 9
[17192538.832000] usb 2-1: device descriptor read/64, error -71
[17192539.060000] usb 2-1: device descriptor read/64, error -71
[17192539.276000] usb 2-1: new full speed USB device using uhci_hcd and address 10
[17192539.684000] usb 2-1: device not accepting address 10, error -71
[17192539.796000] usb 2-1: new full speed USB device using uhci_hcd and address 11
[17192540.204000] usb 2-1: device not accepting address 11, error -71


I took it to a windows machine and it didn't work.Is it broken?
Anyone help me?

Try reformatting the usb media, it looks/sounds like the file allocation table is corrupt.

Any data on the media is lost, sorry

Thanks a lot, but could you tell me how to format it?
when i plug it in,there is no /dev/sda or /dev/sda1.

Are you sure??? What does the typed command show?? /sbin/fdisk -l

You say you have Windows, use it to reformat the media as FAT32 or VFAT (whichever term you like best).

there is no output of the command.
I will try it in windows again.
Thanks

Why do the vendor: and model: strings not appear? If you know that information you can go to the vendors site and look for downloadable repair/recover utilites.

look here:
http://www.linuxquestions.org/questi...09#post2906709