I attempted to take an image using the dd command from one external hard drive and store it on another external hard drive using both ports on the Adaptec USB 2.0 card (an external hard drive in each of the two ports of the card). Well, it doesn't work and gives me a simple Input/Output error. The external drives are NTFS volumes and I can copy files from one to the other with no problem. Any thoughts on why cp works and dd doesn't?