Do I need to do both and what is the difference, really? Understand that Time Machine is hourly and Backup is setup or manually run. I have one external, and Leopard told me I needed to reformat to support Time Machine. Did that, all good, but now when Backup runs, it doesn't see the external (whose icon has now changed to green and says "Time Machine Backups". Also wondering if my MBP's hard drive dies, can I boot from the external with backed up files from Time Machine and Backup? Assume I also need the Leopard disc for that. Sorry if this question is posted somewhere else, though I did search for it for some time with no luck. Thanks!