When a Mac does not boot up due to some software or hardware problems, I read you can use the target mode using another Mac or make a bootable image on the external HD (before the problem happens) and boot up from that external HD. I have 4 Macs already with 5 external HDs. I am weary of using Maxtor's onetouch (retrospect programs) to making the bootable copy on the HD (I feel there can be some data corruptions when software try to make that bootable copy and retrieve that data back to a repaired or new HD). So my back up plans are simply to back up my home folders (mostly documents) without using a 3rd party back up program. Except for the bootable copy of the HD (ie. all the files including systems files), is there any major difference in accessing a troubled Mac via the "target mode" or "bootable external HD?" Does either method achieve the goal (to fix the HD if it is fixable and to retrieve the data)?