Before we get into specifics, you should know that there are two different kinds of backups: backups of your data, and backups of an image of your hard drive.

The one that comes to your mind first is a backup of your data – basically just a copy of your files and folders. It might be done by manually copying them or by running a backup program; the extra copy of your data might be in another folder on the hard drive or on an external hard drive or on a USB stick or online. If you’re running a backup program now, it is likely to be backing up your data.

Another kind of backup has become prominent recently, though, primarily because of technology from Microsoft called “Shadow Copy” or “Volume Snapshot Service (VSS).” It originally appeared in Windows XP, was given a much greater role in Server 2003, and is now an integral part of Vista and Server 2008 as one of the most important tools on our computers and servers.

The technical details are interesting but let’s skip past them to the thrilling conclusion. The shadow copy service coordinates business applications, file-system services, backup applications, fast-recovery solutions, and storage hardware to permit images to be created of an entire hard drive. The images can be used to quickly return the drive to exactly where it was when the image was created, regardless of whether files were open or databases were running.

The easiest way to understand the difference is to think about what happens if your computer won’t start because the hard drive has crashed. Let’s say you have an external hard drive with a backup. You run to Best Buy and buy a replacement hard drive and attach it inside the computer.

  • If you have a backup of your data, you can’t do anything with it yet. First you have to install Windows onto that empty hard drive from the original CD/DVD. Resolve whatever problems there are with particular hardware that doesn’t come to life right away. Then get the updates released since the Windows CD/DVD was pressed (frequently hours of downloading and installing). Set up your desktop. Install the programs you use if you can find the installation CDs.

Now you can turn to that backup of your data. If a particular program was used to create the backup, you likely can’t restore those files until the same program has been installed on the rebuilt computer. Then, and only then, you’ll do the restore. It’s easy to put your documents and pictures into the right folders, quite a bit harder to figure out how your email was stored and what it means to restore it to the same program on the rebuilt system. Each individual program is a small challenge – where does Quicken store its data, which file holds Quickbooks data, where does iTunes expect music files to be located? If Outlook was running when the backup program ran overnight, the chances are the backup skipped the open Outlook data file – are you careful to close programs before the backup program runs?

  • If you have a backup of an image of your hard drive, the process is much different. Typically you start the computer from a special CD/DVD in the drive. (For Vista, it’s the Vista install DVD, as we’ll see.) It takes a few keystrokes to begin the process of restoring the image onto the blank hard drive. In a short time (frequently 15-30 minutes), the computer restarts and resumes working exactly as it was working at the moment the image was created. That’s it. You’re done.

That sounds pretty compelling but we’re not done yet. The backup screen for Vista Business presents the two choices very directly. Tomorrow Next week let’s start to look more closely at the question it poses: Which type of backup should I make?


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