When I use umount to unmount my usb drive, the light on the usb drive blinks and after that the light is still there (without being turned off like what you normally see on M$ Windows system). When I check my FreeBSD system (FBSD 7.2), there's no usb device so I guess the usb drive has exactly been unmounted successfully. But then why is the light on the usb drive still on? Is it safe to remove the usb drive in this state?