The slasdot article http://linux.slashdot.org/article.pl.../03/08/2345250 describes a Puppy live CD that can actually save data back onto its own disk!
Quote
The PC boots with a multi-session CD inserted in the CD-burner drive -- thus, Puppy Linux automatically knows which drive is the CD-burner, in case you have more than one CD/DVD drive. Then you use Puppy in the normal way. At shutdown, all the changed files in your home directory are saved back to CD. That's it. Next time you boot, all the personal files are restored!
Unquote

Is there a roadmap for Knoppix also for a similar feature ?

Regards,
RSM