Knoppix USB Based FAQ

"What you'll need :

* Knoppix or an already stripped down version with a kernel with cloop-support (i.e. Debian).

If you want to boot Knoppix from USB stick, you must also modify miniroot.gz to include usb-uhci.o, usb-ohci.o and usb-storage.o, otherwise /linuxrc can't mount the stick and find the cloop image.

* bootable USB keydrive.
* Computer with BIOS capable of booting from USB keydrive (select USB-ZIP).
* syslinux or grub for booting."

http://www.knoppix.net/wiki/USB_Based_FAQ