Please don't just drag and drop like OS 9. OS X is BSD based and BSD is Unix based. So the move has to have permissions set right and the move has to be "blessed" so it can boot. Luckily there is a free-ware/donation-ware program that will do all that. The program is called Carbon Copy Cloner. I use this program to copy to a firewire drive and I can boot off that firewire drive with no problem. I even sent money to the developer because IMHO the program works better than most commerical backup applications.