Information Technology Reference
In-Depth Information
Exploring OS X: Autosave and Versions
Since the computer was invented, users have been familiar with saving files. OS X
Lion and subsequently Mountain Lion made a brave step away from this strict
requirement. In apps that are compatible with the new autosave and versioning fea-
tures, files are automatically recorded to disk as soon as you start editing—even if
you haven't chosen to save them or given them a name. Create a file in TextEdit, for
example, and you can quit the app right away. When you next open TextEdit, the
unsaved file will be there waiting for you.
In those same apps (that is, they were either designed or specifically updated for
Lion/Mountain Lion's new features), OS X also periodically saves versions of files so
you can step back in the file's history to restore an older rendition. Every time you
close a file, a new version is recorded, and a new version is also recorded after every
hour that passes while the document is open. You can also hit
COMMAND
+
S
to save a
version whenever you want, such as before making a big edit, although this will also
update the saved file in the standard way.
To restore a previous version, just click File→Revert to→Browse All Versions on the
menu (or click the filename in the title bar and select the same option). This will open
a timeline view of the document rather like that offered by the Time Machine backup
function, but, crucially, Versions can work independently of Time Machine. In fact,
there's no requirement for Time Machine to be set up.
All you need to do is select the version of the file you want from the vertical timeline
display at the right of the screen. The current version of the file will be shown on the
left, with the archived version on the right. When you find the one you want to restore,
just hit the button beneath.
Even if you restore to an older version of the file, the version of the file you're aban-
doning will also be added to the version list, making the purpose of autosave and
versions very clear: except for a catastrophic hard disk failure, it is impossible to lose
any data, and you therefore don't have to worry about saving files.
Tip 253
Clean Caches for Smooth Running
To speed things up, most OS X applications and system tools cache data on
the hard disk that they access frequently. While this works fine most of the
time, sometimes the caches can become corrupted, and this can slow down
either the application or the entire system. Therefore, if you run into a myste-
rious problem of an app working slowly or perhaps not working at all, deleting
