Time Machine (Apple)
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| developer | Apple Inc. |
| Publishing year | 2007 |
| Current version | 1.3 (October 16, 2014) |
| operating system | from macOS 10.5 |
| category | data backup |
| License | proprietary |
| German speaking | Yes |
| Time Machine website | |
Time Machine (English for time machine is) a data protection software from Apple , since Mac OS X Leopard in the (10.5) operating system macOS is integrated. The program can be used for the automatic backup of all computer data and settings.
function
The Time Machine in the operation of the computer snapshots of the file system ( "snapshots") and stores it on any drive or in a grow-along disk image , called a "sparse bundle". At the beginning there is an original version of the directories to be backed up, which are mirrored. For each subsequent backup process, a new directory is created next to it, named after the date, the device name and the time. All backed up files are saved only once to save storage space; Hard links are created for unchanged files .
The backup can be carried out until the storage medium (usually an external hard drive ) is full. Time Machine then automatically purges the oldest records to delete them. Time Machine therefore does not create a complete archive , but only a series of images of a file system over time. It only works reliably if its integrity is intact , especially as long as all the links created are intact.
In continuous operation, the backup can be carried out "alongside" (usually at intervals of one hour) or selectively, e.g. B. if the target drive is only connected temporarily.
Local data backup
Time Machine can back up data to internal hard drives or external storage media connected to the computer via USB , FireWire, or Thunderbolt . An HFS + -formatted hard drive or partition is required for this. This storage medium must not be the start volume of the computer.
Data backup over the network
For data backup over the network, Apple offered the Apple Time Capsule (with built-in hard drive) from 2008 to 2018 . Alternatively, an ordinary router with a connected USB hard drive or NAS can be used, especially since most manufacturers of routers and network storage devices for home use offer support for the Time Machine.
Scope of data backup
Time Machine can also back up data for drives that are directly connected to the Mac. In addition to the built-in hard drive on which the operating system runs, the backup can also include other external drives connected directly to the Mac. Conversely, this means that network drives as SMB - shares can not be secure with Time Machine.
The user can specify which drives are to be backed up in the Time Machine configuration.
Operation of the Time Machine
Selective data recovery
If data is corrupted or lost , the user can restore it through Time Machine. First of all, the user has to call up the respective program in which he is measuring data. This can be a file in the Finder, for example, but also an e-mail in Apple Mail or a contact entry in the Apple address book . In the second step, the user starts the Time Machine program.
Now all windows are hidden except for the window in which the user is missing his data (Finder, Mail ...). The background changes to a 3D universe with a chronological order of windows one behind the other with a timeline on which all backup times can be seen. By selecting a point in time, the respective previous data status can be viewed. If the missing data or the correct version has been found, all or only part of the past can be brought back to the current (new) version with one click.
Which window is displayed in the 3D stack depends on the Time Machine integration of the respective application. With Apple Mail , Contacts or in older systems with iPhoto , the respective program can be displayed with the data available in the past (previous mails, notes, addresses, photos, etc.). Other programs do not offer such a deep Time Machine integration - in some cases this also applies to applications from Apple, such as Aperture or iTunes . The Finder window then appears here , and you have to use the file names to get the correct information. In Office programs in which the user constantly works with file names and consciously stores everything in the Finder, the Finder is displayed in a task-oriented manner. In applications in which the software takes over the file management and the user works without a file name (such as iTunes, Aperture or VMware ), retrieval can be a bit more difficult. The software manufacturers have expanded the integration of Time Machine compatibility more and more over the years. One example is VMware Fusion 4.0, which, in contrast to earlier versions, displays a real GUI instead of a Finder window to make it easy to find the correct version from the past .
Complete data recovery
If the entire system needs to be restored, for example after a hard drive change, the computer has to be booted from the recovery partition in macOS recovery mode, then the entire Time Machine backup can be restored. The migration to another computer can be carried out with the migration assistant , a Time Machine backup can be used as the source.
More options
Time Machine backups can be accessed from any macOS system, be it via the Time Machine utility or by manually mounting the savings bundle in which the backup is stored.
Limits and criticisms
As with any other differential data backup , if the file is changed, the entire file is backed up again. As a result, Time Machine is less suitable , for example, for backing up virtual machines that consist of a single large file. The same applies to e-mail clients in which all mails are stored in a single large mailbox file by default, such as Mozilla Thunderbird . In such cases, an incremental data backup would be more suitable. Package files (in the Finder they appear like a file to the user), on the other hand, are treated as folders by Time Machine and only the files that have been changed in them are backed up when changes are made.
The following points of criticism have been gradually resolved over several generations of new Mac OS versions:
- Before version 10.7, it was not easy to use Time Machine and FileVault at the same time , because before that, data backup could only be carried out with logged out users. This problem has been fixed in Mac OS X Lion (10.7) by now encrypting the entire hard disk (only the user directory was encrypted in 10.4, 10.5 or 10.6). The saved data is also encrypted.
- Before version 10.7 it was not possible to synchronize two data backup sets. This means that if you create backups on a USB hard drive while you are out and about, you could not enter them into your home Time Capsule beforehand. This shortcoming has also been remedied.
- As of version 10.8, more than one hard disk can serve as a backup medium. If more than two hard drives are configured for this, Time Machine distributes the data evenly. This option is useful to keep a longer history or to be able to take a record with you on the go and still have a record at home with a certain fall-back protection.
Web links
Individual evidence
- ↑ T. Krazit: Apple New feature sends users back in time . In: CNET news , August 7, 2006
- ↑ Information on macOS recovery. Accessed May 31, 2019 .
- ↑ Transferring content to a new Mac. Accessed May 31, 2019 .