Knoppix
 

Is KNOPPIX EXACTLY the same as a Debian installation? Which version is it (stable, etc.)

And how can I install deb packages on KNOPPIX?

Knoppix is created from the list of Debian packages. It's its own verssion... Not an exact Deb stable/testing/unstable, but a combination of packages from different levels.

You can use apt to install packages... You'll just have to set-up your /etc/apt/sources.list to point to the servers you want to use.

and you can break knoppix easier than debian because its a hybrid of debian variations and not really ment to be installed on the hard drive YES you can do it BUT its not its primary function