persistence on usb key

[DOM5556]

Tell us the output from

df -h

THANKS FOR YOUR ANSWER OUTPUT IS
knoppix@Microknoppix:~$ df -h
Filesystem Size Used Avail Use% Mounted on
rootfs 20G 3.0G 17G 16% /
/dev/root 20G 3.0G 17G 16% /
tmpfs 2.0G 8.0K 2.0G 1% /tmp
udev 20M 4.0K 20M 1% /dev
tmpfs 2.0G 0 2.0G 0% /dev/shm
knoppix@Microknoppix:~$