I remastered a liveCD, and put the liveCD image on a CF card in an IDE adapter (for a silent 100% solid state PC). Even if I had write access to the CF card when it is running, it's a liveCD image so I can't just stick the contents into the /etc directory of the CF card. So the calibration file has to be copied to the /RAMdisk/etc directory upon bootup, overlaying the filestructure that the liveCD is creating.

Since the touchscreen is initialized during bootup I need to copy the calibration data from my thumbdrive onto the ramdisk at the same time the LiveCD is copying stuff to the RAMdisk.

Morphix has a cool way of doing it, called "translucency". With morphix, you just put the files you want overlayed into the RAMdisk in an uncompressed folder on the liveCD, which Morphix named "/copy". I wish Knoppix had a similar feature out-of-the-box. It's a sweet way to do things.

ps - I'm currently using knoppix 3.7, but I can just as easily use the latest knoppix (UnionFS is from 3.8 on up, yes?).