Time Machine is Apple's built-in backup software. Time Machine was first introduced on OS 10.5 Leopard.

Apple Time Machine logo

Although the implementation details of Time Machine have improved from the introduction until the current version, some general characteristics of Time Machine are:

  • Each backup is a full backup and can be navigated using normal filesystem / folder structure to restore files or directories.
  • Each backup normally takes the same time as an incremental backup since hard links are used for files unchanged from the last backup. Only files that are changed or new get backed up and use space on the destination backup volume.
  • Various error checks exist to detect problems with the destination.
  • When insufficient space exists on the destination for the estimated size of an upcoming backup, Time Machine will delete older backups to make space for the current changes.