Some computers do not support boot from USB, but do have USB ports. On these machines you can boot your Slax operating system off USB using a helper CD.

 There is a simple way to accomplish this. 

• download the Slax ISO http://www.slax.org/get_slax.php?download=iso
• extract the ISO. on linux you can mount the ISO and copy it to a new directory on your hard drive
  •  mkdir /tmp/cdrom; mount -o loop /dev/cdrom /tmp/cdrom;mkdir /tmp/slaxcd;cp -R /tmp/cdrom/* /tmp/slaxcd/
• Now you can modify the copy of the ISO in /tmp/slaxcd. To make the CD read the operating system from the USB remove /slax/livecd.sgn. This is the only change you have to make. You can also remove /slax/base and /slax/modules to make the helper CD smaller. I have not investigated if other files can also be omitted.