In a terminal run
dmesg |tail -n 15 immediately after the pen drive is plugged in. You should see a reference to sdX (X being a, b, c)
The output should be like
Code:
[65253.850029] usb 2-1: new high speed USB device using ehci_hcd and address 2
[65254.002823] usb 2-1: configuration #1 chosen from 1 choice
[65254.043682] Initializing USB Mass Storage driver...
[65254.043867] scsi6 : SCSI emulation for USB Mass Storage devices
[65254.043953] usb-storage: device found at 2
[65254.043955] usb-storage: waiting for device to settle before scanning
[65254.043966] usbcore: registered new interface driver usb-storage
[65254.043969] USB Mass Storage support registered.
[65259.040104] usb-storage: device scan complete
[65259.040459] scsi 6:0:0:0: Direct-Access CBM Flash Disk 5.00 PQ: 0 ANSI: 2
[65259.040846] sd 6:0:0:0: Attached scsi generic sg2 type 0
[65259.042337] sd 6:0:0:0: [sdb] 2062336 512-byte logical blocks: (1.05 GB/1007 MiB)
[65259.042819] sd 6:0:0:0: [sdb] Write Protect is off
[65259.042823] sd 6:0:0:0: [sdb] Mode Sense: 0b 00 00 08
[65259.042825] sd 6:0:0:0: [sdb] Assuming drive cache: write through
[65259.044570] sd 6:0:0:0: [sdb] Assuming drive cache: write through
[65259.044573] sdb: sdb1
[65259.046701] sd 6:0:0:0: [sdb] Assuming drive cache: write through
[65259.046705] sd 6:0:0:0: [sdb] Attached SCSI removable disk
Post the result here and we can take it further.