I love time machines: my favourite series of films is Back To The Future. (Jo and I even had a time machine wedding cake in 2007.) But this post isn’t about science fiction, it’s about the onboard backup software in Apple computers.
Time Machine is more than just a simple backup software: it creates ultra-compressed snapshots of your computer on a regular basis, so that you can view the history of any folder or file on your hard drive. Instead of creating masses of full copies of the entire hard drive, it analyses what has changed and creates a new version containing what’s changed since the last analysis.
That means that (for example) on my office computer, I can check back on the status of web project files from last year, which may have been changed dozens of times since, to see where a bug was introduced. The backups are stored on an external hard drive, so if the computer breaks down, the files (and all of their previous iterations) are safe. Delete a file or folder by accident, and you can recover them from any of the previous stages of the backup history.
One additional usefulness is if you buy a new computer. One of the time-consuming tasks of setting up a new office computer was the re-installation of software, software licenses, preferences, files, and so on. I remember that it used to take at least a full day’s work to migrate everything from a previous computer to a new computer, costing valuable time and often meaning a delay in being able to use the new machine at all.
These days, it’s easy. Simply connect the external hard drive containing the Time Machine backups to the new computer before it’s first used and specify that the new computer should “restore” itself from the latest Time Machine version. Leave it to run overnight, and when you arrive in the office the next morning, you will be greeted by the message that your new computer is ready to go, in exactly the same state as you finished using the previous one. (Assuming that the last action before shutting down the old computer was to make sure all software is up-to-date, repair all the permissions and make a final Time Machine backup.)
The only slight delay to the process may be waiting for a time for Apple Mail to re-initialize all of your previous messages: for me this morning, the process for 110,000 emails has taken around an hour to complete.