John Carter to the rescue! This article on protecting your Mac against a catastrophic hard drive failure is still worth looking at. John refers to Macworld Hints as "THE place to look for tips and techniques about the Mac. However, you can spend a whole lot of time filtering through the thousands of submitted articles and comments to get a concise answer for your question. You might find just what you’re looking for or you might feel like you’re wasting your time. "For example, I did a search for 'time machine backup' (using the advanced search and searching titles only) and got 516 hits, the first 14 were comments and the rest were hints about different aspects of using Time Machine in connection with backups." John advises, "One of the best hints is 'Make a Bootable Backup.' This is one way to protect yourself against a catastrophic hard drive failure, but it doesn’t give you the option to boot up from an external hard drive and continue using the Time Machine disk for backups." So, read how to do it, and then do it. It's easy and it's logical.