Windows 8 includes a new file system called ReFS (Resilient File System). It's compatible with most NTFS file features, and, as the name suggests, it adds features to improve data integrity. Features left out include BitLocker, compression, and 8.3-format short filenames. What ReFS brings to the table is improved data verification and auto-correction: ReFS continually scans the file system, including rarely used older files, to ensure they haven't become corrupted, repairing bad disk clusters and moving data as necessary. Note, however, that ReFS works only on secondary drives, not boot drives. Your boot drive will still be NTFS.
If you're worried about encountering a problem that may force you to reinstall Windows, you'll be pleased to learn that reinstalling Windows is now much easier; in fact, Windows 8 provides multiple levels of system repair.
The Reset option nukes the hard drive and reinstalls Windows from scratch. You can use this option to get the machine back to a factory-fresh Windows install, without the need for a new Windows key or the Windows setup disk.
If you prefer something less drastic, the Refresh option resets important Windows settings but maintains your personal files and installed Windows 8 apps. Note, though, that it doesn't keep desktop applications, so you might wish to first uninstall or deregister software that will need reinstallation and activation.
Finally, you can customize the refresh process by using the "recimg" command-line tool. Using recimg makes an image of your current version of Windows--including installed desktop applications--and makes that the default image when you refresh your PC. Then, when you run Refresh, you'll still reinstall Windows from scratch, but you'll also retain your desktop applications. You will need to run recimg occasionally if you have desktop programs that you don't want to reinstall all over again.
Windows 8 and SkyDrive
The new operating system ships with a Windows 8 app for the SkyDrive cloud-storage service. If you have a Microsoft account, you begin with 5GB of SkyDrive space.
Out of the box, SkyDrive shows up as a Windows 8 app, but it does not appear in the file manager on the desktop; to make that happen, you need to download and install the SkyDrive desktop application. Once you download the application, install it, and link it to your Microsoft account, both the Start screen and desktop become coupled to your SkyDrive.