14 DAY TRIAL // Data loss prevention technologies have evolved in Windows Vista in comparison with Windows XP. In this regard, Microsoft has made available Shadow Copy in Windows Vista Enterprise, Business and Ultimate. Shadow Copy is a feature that saves point-in-time copies of the files that are being modified concurrently with the user's workflow. Being turned on by default in all the Vista editions in which it has been implemented, Shadow Copy will allow users to restore previous versions of files even if they have modified the documents past the point where they lost all the data. Microsoft informed that Shadow Copy saves incremental copies of the files and that therefore the disk space occupied by shadow copies will be minimal.
"In Windows Vista, System Restore is now based on the VSS technology, which keeps track of block-level changes across your entire volume(s). In contrast, Windows XP System Restore would keep copies of changed system files by using a file system filter. The Windows XP method isn't performance efficient because it works above the file system level, impacting every system operation. It is also not consistent as it doesn't have needed information across the entire volume. It wouldn't restore, for instance, applications that place binaries (purposely or maliciously) in the user profile," explained Eduardo Laureano, the Program Manager for System Restore.
Laureano also redefined the perspective Microsoft has over "minimal." The fact of the matter is that shadow copies can grow to occupy as much as 15% of a volume. This is in fact the maximum limit. They will not expand over that, and the growth is strictly correlated with the volume of changed blocks on a system.
"Once they reach their cap, 15% of your volume, older shadow copies will be deleted to free up room for new ones. With these improvements in place, the Windows Vista solution allows for a more reliable (restore points are readily available), robust (supports a much broader set of repair scenarios) and efficient (seamless impact on performance) System Restore," Laureano added.