Continuing our series detailing the new features in Mac OS 10.5 “Leopard”, this week we look at “Time Machine”, Leopard’s innovative way of accomplishing a task that many aspire to accomplish but few actually do.  I’m referring, of course, to consistent and faithful backing up of our important computer data – contacts, photos, financial records and other personal documents, purchased music and movies, etc.

Now, applications designed to manage backups have been around for quite awhile.  However, while effective, these solutions offer relatively mundane interfaces, and are mostly third-party “add-ons” to the operating system.  Despite my witty title (I know, I know – you’ll be the judge of that), Leopard’s Time Machine is really a revolutionary approach to backing up data, as it functions at the system level, and can be accessed from within many of Leopard’s applications.

Obviously, with any backup scheme designed to protect your data in the event of a catastrophic hard drive failure, you need somewhere besides your computer to back up to.  Time Machine can back up to any FireWire or USB hard drive – you can even use Time Machine to back up to another Mac.  I recommend an external hard drive, with at least as much storage space as the hard drive on your Mac.  A quick check on pricegrabber.com today revealed 250 GB USB2.0 hard drives available for under $75 – a small price to pay for peace of mind.

Let’s walk through using Time Machine for the first time.  Connect your external drive to your Mac.  Open System Preferences and click on the Time Machine button in the System section.  Turn on Time Machine by clicking “ON” (duh).  Select your backup disk (if you have more than one plugged in) with the “Change Disk” button.  Click “Options” to choose any files and folders on your Mac you do not want to back up.  Click “Done” and Time Machine starts backing up your Mac.

For the initial backup, Time Machine copies all the files on your Mac to the external drive, without compression, and skipping caches and other files that aren’t required.  Subsequent backups are “incremental”, meaning only files that have been added or changed since the last backup are copied.  Assuming you leave the backup drive attached all the time, Time Machine saves hourly backups for the last 24 hours, daily backups for the last month, and weekly backups for anything older than a month.  In a word – it’s smart.

If you’re in the middle of the backup process and have to shut down – no problem.  Time Machine remembers where it was and resumes the backup when you start up again.

Say you have more than one Mac in the house.  You can backup multiple Macs to the same hard drive – Time Machine stores the data in a file system that won’t get confused.

The real beauty of Time Machine is its interface.  Let’s look at a real-life scenario.  You accidentally delete a bunch of photos stored in iPhoto.  They’re gone. You can’t find them anywhere.  Wait.  The last time you remember seeing them was last week.  With iPhoto open, you click on the Time Machine icon in the Dock.  Cascading panes of past iPhoto windows open against an eye-candy deep space background.  With an animated timeline or simple forward and back arrows, you navigate back to the iPhoto window containing your lost photos.  Click on the photos, click a “Restore” button, and your lost photos are returned to your present-day iPhoto library.

Time Machine works the same way with Address Book contacts, email, etc.  It’s amazing.  Give it a try.