Time Machine is a backup utility by Apple Inc. It is included as part of Mac OS X starting with OS X 10.5 "Leopard". Time Machine supports backing up data to hard disks connected to a Mac and AFP network shares.
Time Machine supports backing up data to hard disks connected to your Mac, AFP network shares and Time Capsule wireless access points. It generally backs up all vital system data, but folders can be excluded from backup using System Preferences.
Time Machine does not back up FileVault protected user accounts while the user is logged in. Log out with the Time Machine drive connected to back up your user data.