Linux on a USB hard drive without USB-FDD BIOS option
I'm interested in buying a USB hard drive for my laptop so that I can run Linux on a separate drive--I have heard that dual boot on the same drive is problematic and furthermore I would have problems freeing up the space.
My BIOS has an option to boot to a USB-FDD, but not USB-HDD, so my questions are the following:
1) Does anybody know if there is a USB hard drive (_not_ a thumb drive) that can be booted using the USB-FDD BIOS option?
2) Otherwise, can I use a boot disk to load whatever pieces of Linux are necessary for USB into memory and just continue from there with the USB drive? If so, how do I set this up?
3) If #2 is possible, am I restricted to a distro like Knoppix?
Thanks a lot for your help.