Apple’s Time Machine backup system is available in Mac OS X v10.5 and above. But if you have a previous version, or prefer not to use Time Machine, you can use one of several alternative methods. To be effective, the backup should be on a separate hard drive. If the main drive of your Mac fails, you can use the backup drive to restore your system and files after replacing the failed drive. Tips Writer Bio

How to Back Up My Mac to a Hard Drive Without Time Machine - 67