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Windows 8: File History explained

File History is a new automated system for continuously protecting your personal files stored in several key locations.

Bohdan Raciborski

Any time your personal files change, there will be a copy stored on a dedicated, external storage device of your choice. File History continuously protects your personal files stored in libraries, desktop, favorites and contacts folders. It periodically (every hour by default) scans the file system for changes and copies changed files to another location. Over time, File History builds a complete history of the changes made to any personal file.

File History was introduced in Windows 8, and gives you a new way to protect your files. It supersedes the existing Windows Backup and Restore features of Windows 7 because it was never  a very popular application. This leaves your personal data and digital memories quite vulnerable, as any accident can lead to data loss.

In Windows 8, Microsoft is actively trying to:

  • Make data protection so easy any Windows user can turn it on and feel confident his personal files are protected
  • Eliminate the complexity of setting up and using backup
  • Turn backup into an automatic, silent service that does the hard work of protecting your files in the background without any interaction
  • Offer a simple, engaging restore experience that makes finding, previewing and restoring versions of personal files much easier

While designing File History, Microsoft used what it had learned in the past and added requirements to address the changing needs of PC users:

  • PC users are more mobile than ever. To address that, File History was optimized to better support laptops that constantly transition through power states, and are being connected and disconnected from networks and devices.
  • PC users create more data and are more dependent than ever on data. So not only is the data that’s currently on the system drive protected, but also any work and data that was created in the past.

When a specific point in time (PiT) version of a file or even an entire folder is needed, you can quickly find it and restore it. The restore application was designed to offer an engaging experience optimized for browsing, searching, previewing and restoring files.

Setting up

Before you start using File History to back up your files, you’ll need to set up a drive to which you will save files. Microsoft recommends you use an external drive or network location to help protect your files against a crash or other PC problem.

File History only saves copies of files in your libraries, contacts, favorites and on your desktop. If you have folders elsewhere you want backed up, you can add them to one of your existing libraries or create a new library.

To set up File History:

  • Open the File History control panel applet.
  • Connect an external drive, refresh the page, and then tap or click “Turn on.”

You can also set up a drive in AutoPlay by connecting the drive to your PC, tapping or clicking the notification that appears, then tapping or clicking “Configure this drive for backup.” That’s it. From that moment, every hour, File History will check your libraries, desktop, favorites and contacts for any changes. If it finds changed files, it will automatically copy them to the File History drive.

Restoring files

When something bad happens and one or more personal files are lost, the restore application makes it easy to:

  • Browse personal libraries, folders and files in a manner similar to Windows Explorer
  • Search for specific versions using keywords, file names and date ranges
  • Preview versions of a selected file
  • Restore a file or a selection of files with a tap or click of a mouse

Microsoft designed the restore application for wide-screen displays and wanted to offer a unique, engaging and convenient way of finding a specific version of a file by looking at its preview.

With other backup applications, you have to select a backup set created on a specific date. Then you have to browse to find a specific folder and then find the one file you need. At this point, however, it’s impossible to open the file or preview its contents to determine if it’s the correct one. You have to restore the file and if it isn’t the right version, you have to start over.

With File History, the search starts right in Windows Explorer. You can browse to a specific location and click or tap on the History button in the Explorer ribbon to see all versions of the selected library, folder or individual file. For example, when you select a Pictures library and click or tap on the History button, you’ll see the entire history of the library. When you click on a specific file, you can see the entire history of the selected picture.

You can easily navigate to the desired version by clicking on the Previous/Next buttons or by swiping the screen. Once you’ve found the version for which you’re looking, you can click the Restore button to bring it back. The selected version will be restored to its original location.

Instead of protecting the entire system (the OS, applications, settings and user files), File History focuses on your personal files. That’s what is most precious and the most difficult to recreate in case of an accident.

Optimized for performance

In the past, most backup applications used the brute-force method of checking for changes in directories or files by scanning the entire volume. This approach could significantly affect system performance and required an extended period of time to complete. File History, on the other hand, takes advantage of the NTFS change journal.

The NTFS change journal records any changes made to any files stored on an NTFS volume. Instead of scanning the volume, which involves opening and reading directories, File History opens the NTFS change journal and quickly scans it for any changes. Based on this information, it creates a list of files that have changed and need to be copied. The process is quick and efficient.

File History was designed to be easily interrupted and quick to resume. This way, File History can resume its operation without needing to start over when a system goes into sleep mode, when a user logs off, when the system gets too busy and needs more CPU cycles to complete foreground operations, or when the network connection is lost or saturated.

File History was designed to work well on any PC, including small form-factor PCs with limited resources and tablets. It uses system resources in such a way as to minimize the impact on system performance, battery life and overall experience.

File History takes into account:

  • If the user is present, meaning logged on and actively using the system
  • If the machine is on AC or battery power
  • When the last backup cycle was completed
  • How many changes have been made since the last cycle
  • Activity of foreground processes

Based on all of these factors, which are rechecked every 10 seconds, it determines the optimal way to back up your data. If any of those conditions change, the service makes a decision to reduce or increase quota or suspend or terminate the backup cycle.

Optimized for mobile users

When File History is running, it gracefully handles state transitions. For example, when you close the lid of your laptop, disconnect an external drive, or leave home and take your laptop out of range of the home wireless network, File History takes the appropriate action as follows:

  • Lid closed: When a PC goes into sleep mode, File History detects the power mode transition and suspends operation.
  • Lid opened: File History resumes its operation at a priority that ensures files are protected without impacting overall system performance, even for gamers. It also waits for all post-“lid open” activities to complete so the system isn’t affected while it’s coming back out of sleep.
  • Dedicated storage device disconnected: File History detects that the storage device isn’t present and starts caching versions of changed files on a system drive.
  • Dedicated storage device reconnected: In the next cycle, File History detects the storage device was reconnected, flushes all versions from the local cache to the external drive and resumes normal operation.

Simplicity and peace of mind

Microsoft designed File History with two objectives in mind: to offer the best possible protection of your personal files and to offer ease of use, simplicity and peace of mind.

If you want to take advantage of File History, you only have to make a few, simple decisions. In most cases, these decisions will be limited to only one: which external drive to use. Windows 8 takes care of the rest. File History operates transparently and doesn’t affect the UX, reliability or performance of Windows in any way. Next month, I’ll cover some of the more advanced backup features of Windows 8 and File History.

Bohdan Raciborski

Bohdan Raciborski is a principal program manager lead for Microsoft. He has more than 20 years of software development and program management experience. His primary focus is developing software and managing teams in areas ranging from enterprise, high availability, and high-performance storage solutions to consumer products for developed and emerging markets.