Live USB: Hard drive utilization?

[Quest]

Here is a couple of questions about hard drive (HD) utilization under Kali 1.0.4 Live USB.
Information on the net is unclear.

1. Does it use the hard drive at all if no drive is mounted?

2. Is the hard drive still active/alive/spinning?

3. Can I shut the hard drive down?

The reason for me asking is for operation during transport, energy and logical efficiency.

[azihak]

it does not use the hard drive unless you want to and mount it