Few days ago I wrote about this problem (http://lists.centos.org/pipermail/centos/2005-June/007086.html). Now, after upgrade I have CentOS 4.1 and problem still exist.
What happens if you:
tail -f /var/log/messages
then plug the drive in? Do you see any associated messages?
Below is a fragment of /var/log/messages
--------------------------------------------------------------------- Jun 20 11:58:15 localhost kernel: usb 1-3: new high speed USB device using address 3 Jun 20 11:58:16 localhost kernel: SCSI subsystem initialized Jun 20 11:58:16 localhost kernel: Initializing USB Mass Storage driver... Jun 20 11:58:16 localhost kernel: scsi0 : SCSI emulation for USB Mass Storage devices Jun 20 11:58:34 localhost kernel: usbcore: registered new driver usb-storage Jun 20 11:58:34 localhost kernel: USB Mass Storage support registered. ---------------------------------------------------------------------
Regards