One of the most talked about features in Apple's upcoming Mac OS X 10.5 is the built-in back-up tool called Time Machine.
For Mac users, Time Machine is big news: it marks the first time Apple has bundled any sort of backup solution with its operating system. (While it's true that Apple's .Mac service once included a basic consumer backup tool, the service is available only to subscribers of .Mac).
Being a Mac OS X backup tool isn't the main reason Time Machine is important. There have been any number of free, shareware and commercial backup tools for quite some time. But Time Machine is a step ahead of competitors because it's designed by Apple as a backup tool for the average computer user, meaning that it is very simple to use, with virtually no management or oversight needed.
Anyone who's seen Apple's demos or screenshots of Time Machine can tell that this is not a typical backup application. When you need to access a backup of any file, folder or item tucked away inside a Time-Machine-aware application, you simply select the appropriate window (such as a Finder window of the folder containing the items you need to recover) and then click the Time Machine icon in the dock.
The window you initially selected remains on display but with two arrows (backward and forward) next to it and with translucent images of the window disappearing into the background of the screen. Each translucent window indicates a previous-generation back-up of the selected folder. Using the arrow keys, you can move backwards or forwards through each backup. As the interface implies, you move backward or forward through the files on your computer based on time.
This approach is not only visually amazing - it does look like something out of a science fiction movie - but it is also incredibly intuitive and easy to navigate. With most backup applications, you need to locate the appropriate backup set, load its catalogue file and then search for either the name of the file or browse through the backup generations based on date. This typically involves looking through file path representations to locate the correct backup set and navigate through it. Even the best backup solutions rely on an interface that is separate from the operating system.
By incorporating Time Machine into Leopard, which is due out by next spring, Apple retains the same basic interface, be it in the Finder or a Time-Machine-aware application. This means the user doesn't have to navigate through an alien file structure. To reiterate the genius of Time Machine: select a file, click an icon in the dock and you're soon looking through past incarnations of the original item you were already viewing. There's no extra navigation except backward and forward.
Going beyond files
One of the smartest concepts that comes from building in Time Machine at the operating system level is that Apple was able create Time Machine APIs that developers can use in individual applications. This means that an application has access to past files, configurations or chunks of data - and users won't need to leave that application to access lost, changed or deleted items. Instead, they can simply click the Time Machine icon while still in the application and, using the same two-arrow interface, go through previous incarnations of the displayed information.
Here's an example: if you are working in iPhoto and make changes to an album (or delete an album) and later realise you need a photo from that album, you can simply use Time Machine to view the album as it was yesterday or the day before - or last month. With a couple of clicks, you can restore lost photos or albums.
The same is true with contact information in Address Book. If you deleted someone's phone number and need to recover it (or if you deleted an entire contact), you can use Time Machine to backtrack and restore the information. This is going to offer users incredible contact management far beyond what is offered by any other contact manager.
What is truly remarkable about both of these examples is that you don't need to be concerned with where the files are stored. You don't need to restore the actual files that Address Book uses to keep contacts information. And for many applications, a majority of users don't know where to find the files anyway, so with traditional backup applications, they wouldn't be able to restore them. That's because until now, backup tools have worked only at the file level.
This integration truly makes Time Machine a paradigm shift in the way users relate to backups.
No configuration needed
Time Machine will function much like Spotlight in that users won't need to be concerned with how it works, just how to access it. Like Spotlight, Time Machine will index the contents of a hard drive when it is first available to the file system. However, instead of maintaining a database for searching, Time Machine will make a backup of the contents and use its database to track changes made to files. Like Spotlight, Time Machine will also be alerted when a file is modified and will create a backup copy of that file and index the changes. All of this will happen automatically, with no need for a user to configure backup sets - other than to identify where back-up data is to be stored - such as to an external hard drive.
Like Spotlight, Time Machine will also allow a user to exclude certain directories or folders. Some of these exclusions will be automatic (such as cache files used by web browsers and other internet/network technologies).
Excluding certain directories may be necessary for a number of reasons. The first is simply to conserve space on a backup drive. Some users may want Time Machine to automatically manage backups of their entire systems; others may only be concerned that their home folders or specific segments of their home folders be backed up. In network environments, Time Machine will likely need to be configured to exclude network home directories or portable home directories for mobile accounts because this could cause problems with network processes, generate excess network traffic and because an enterprise-level back-up solution should already be in place.
All in all, there is a great deal of reason to be excited about Time Machine. It will truly offer users backup abilities that have so far been limited primarily to larger organisations - and it will do so at only the cost of storage space. More important, it will offer a uniquely easy-to-use back-up solution, one that users will be able to access without needing to really think about complicated configurations that have until now been part of traditional backup applications. The fact that this powerful tool will be included free with Leopard puts it at the top of the list of changes coming to Mac OS X - at least among the features announced so far.