A: Windows 8 File History is a new feature that protects data files on your computer in Libraries and on the desktop, in addition to your Favorites and Contents. Once an hour (by default) it copies any changes to an alternate location.
In addition to just copying new data, a history of the data is maintained on the alternate location, allowing you to view a history of the data for previous points in time-- via the History button in Explorer. History shows the different versions of Libraries, folder and individual files.
File History is enabled and managed through the File History control panel applet. Advanced settings allow more control over the amount of space to use as a cache (used when the target for File History, such as an external hard drive is not available), how often to save copies of files, and how long to keep saved versions (the more history is stored, the more disk space required). See the screenshot below.
Windows 8 Advanced Settings in File History Control Panel Applet
The File History setup is also available when a new hard disk is attached to the system, at which point one of the options is to use the new drive for File History. This will then launch the File History configuration when selected.
Windows 8 File History Dialog Box
File History can be disabled using Computer Configuration, Administrative Templates, Windows Components, File History,Turn off File History Group Policy setting.