doesn't matter man, think about Sony's rootkit stuff. Viruses/Spyware/malware can be embedded into any file... then it spreads. If the external hard drive is ever connected to your computer... poof... all files infected. Ok so the root of the problem, you need 1 way communication, so CD-R recorded on main machine then copied to the secondary drive... The issue is, no matter what you do, your main computer will get infected. There are backdoors, trojans, worms on your computer already...