The kernel will already be loaded into memory (RAM), and this should work for the most part.

Though unconfirmed, I have heard tails of Windows (yes, Windows!) being formatted while it is still running. Windows is usually more obstinate about such things.

Of all the approaches posted here, DD is by far the best. It's fast, it's clean, and it's error-proof. The above script is dangerous as it won't get everything, plus it's going to be terribly slow in comparision to dd.

The suggestion of using something like Knoppix for the dd operation, though, is definitely best. This way you can get in the habit of doing this even on machines that do not have Perl available.