About Time Machine
Time Machine is included with all Mac operating systems beginning with OS X Leopard (10.5). It requires an internal or external drive onto which it automatically backs up your Mac as you work. Time Machine was a revolutionary approach to backing up when it was introduced. The revolutionary part wasn’t the backup process, or how creative the user interface was, or how well Time Machine pruned old backups. All these things had been seen before in backup applications. What made Time Machine a winner was that it was so easy to set up and use that people actually used it. With Time Machine, Mac users can back up their computers without thinking about the backup process.
Set Up Time Machine
Setting up Time Machine amounts to selecting the drive or drive partition you want to dedicate to your backups. Once you do that, Time Machine takes care of almost everything else. Time Machine notifies you when it deletes old backups unless you turn off the notification. You can also add a status icon to the Apple menu bar. For the most part, that’s it. After you select the drive for the backup in the Time Machine system preferences, no other settings are required to set up or configure it. Select Back Up Automatically or turn on the Time Machine switch, depending on your OS version. The system starts backing up automatically. You can access a few options by selecting Options in the Time Machine preferences screen:
Exclude files or folders from the backup by entering those in an exclusion list.Allow a Mac laptop to back up while on battery power.Turn off the notification when Time Machine deletes old files.
There are other options you can use, such as using multiple drives to store your Time Machine data. However, the advanced settings are hidden and not needed by most casual users.
How Time Machine Performs Backups
The first time it runs, Time Machine performs a full backup of the Mac. Depending on how much data you stored, the first backup can take a while. After the initial backup, Time Machine performs a backup every hour of changes that occur. This means you lose less than an hour’s worth of work in the event of a disaster. One of Time Machine’s benefits is how it manages the space it has for backups. Time Machine saves hourly backups for the last 24 hours. It then saves daily backups for the past month. For data that’s older than a month, it saves weekly backups. This approach helps Time Machine make the best use of available storage space and keeps you from needing tens of terabytes of data to keep a year’s worth of backups on hand. Once the backup drive is full, Time Machine deletes the oldest backup to make room for the newest.
User Interface
The user interface consists of two parts: a preference pane for setting up the backups and the Time Machine interface for browsing through backups and restoring data. The Time Machine interface displays a Finder-type view of your backup data. It then presents the hourly, daily, and weekly backups as stacks of windows behind the most recent backup. You can scroll through the stack to retrieve data from any backup point in time.
Accessing Time Machine Backups
Open a Time Machine backup by clicking the Time Machine icon in the Mac Dock or double-clicking the Time Machine icon in the Applications folder. Scroll backward through time using the time scale on the right side of the Mac screen or the arrow buttons at the right of the stacked desktop screen. You can navigate each screen and view each file. When you find a file you want back on your current-day Mac, select it and click Restore.
