as we all know there is a software called "deep freeze" which you probably know what it does.

Anyway, after some googling I noticed that kind of software(s) called sandboxing or virtualization software however, Im not quite sure since my further searches failed me.

So, here is my question:

How does deepfreeze actually works ? If it were making image of everything in computer(its called virtualization I guess) it would take so much space. If it were creating index of every file and checking them regulary, then it would make my computer "freeze".

So whats the magic ? How does it actually works ? does it realize when I download files by some way ?