J.D Biersdorfer from the New York Times did an article for the Personal Tech column entitled "Backing Up is Not So Hard" which outlines the difference between file-based and image-based backup software.

One of the core features of Windows Home Server is the image-based backup software solution that automatically backs up your home PCs every day.  The cool thing about the home server solution is the single-instance storage technology that we developed for the storage of multiple home computer backups across time and across multiple PCs.  You can read more about this patent pending solution in the Windows Home Server Home Computer Backup Technical Brief.

Backup may be easy, but how easy is restore?  An image-based backup solution (or any backup solution for that matter) should be judged by how easy it is to restore a PC, and with Windows Home Server it is 6 simple steps (really it is only 3 steps, as 3 times you merely have to click a Next button):

1. Boot the Home Computer Restore CD to launch the Restore Computer Wizard
(just press the Next button)

2. Enter the password for your Windows Home Server
   
3. Confirm that you want to restore the PC (just press the Next button)
   
4. Pick which backup you want to use to restore from
   
5. Confirm that you want to restore all hard drives or just a given hard drive
   
6. Confirm that you are ready to initiate an image-based restore of 1 or more of the hard drives from the backup stored on your Windows Home Server
   (just press the Next button)
   

Currently on my home server, I have 2 PCs that are being backed automatically every day.  I have 27 image-based backups of my Desktop PC and and 30 image-based backup of my Windows Media Center PC.  These 57 image-based backups only take up a total of 90 GB of storage on my home server.   Please read the Technical Brief to understand how this is possible ...

I consider image-based backup using single instance storage to be a key feature of any home server product.  People should no longer even consider file-based backup solutions or solutions that consume large amounts of disk space to store multiple backup images that contain a lot of similar files, applications, etc.  I sleep a lot better at night knowing that my Windows Home Server is doing an image-based backup up my PCs every day.

t.