hard drives not getting detected

[pramod9964]

my both hard drives

toshiba 500gb
western digital 500 gb
are not getting detected
i have connected it through powered usb hub

even when am using
$ cat /etc/fstab

my log is

Terminal

#
#
#
proc /proc proc defaults 0 0
LABEL=xbian-root-btrfs / btrfs subvol=root/@,thread_pool=1,rw,compress=lzo,noatime,autodefrag 0 0
LABEL=xbian-root-btrfs /home btrfs subvol=home/@,thread_pool=1,rw,compress=lzo,noatime,autodefrag 0 0
UUID=8B12-9112 /boot vfat defaults,noauto,user,gid=0,uid=0 0 0
xbian@xbian ~ $

so kindly tell me where am going wrong