Some problem about usb mass storage device

Dear linuxers,
I have a usb mess storage device.
My OS is rh as3 update2.
Each time I use the command
mount -t vfat /dev/sda1 /mnt/usb
I got the error "the device is not a valid block device".
I found from google that I should install the module sd_mod
I use the command
insmod sd_mod
modprobe sd_mod
lsmod
I really found the sd_mod module.
But it is signed as unused.
How can I make it useful since I still can't use my usb mass storage device.

Could someone be kind enough to give some hints?

Thanks in advance. :slight_smile:

Which other modules do you have loaded?

At least sr_mod module.
And the usb's chip driver module. isb_uhci. :frowning:
So I'm really confused why I can't use my usb device.