I haven't played with knoppix in years but remember it fondly back 10 years or so ago. Always kept it handy.I like Knoppix. I've had a reasonably up-to-date version on a flash-drive for years.......the sheer quantity of stuff KK manages to cram into it is unreal. Including Compiz.....and the amazing rotating desktop cube!
It was part of the original inspiration for Puppy, of course....
absolutely everything is external to the system itself.
I started with Knoppix 6.7. Went going on with 7.6. It was very well as replacement, when XP did need an other mainbord. Took some months, from different reasons.I'm not entirely clear on whether you can only install this on older hardware, but.......I