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date 17.Mar.2013

■ Previous Versions: Windows built-in version control

Windows reliability has gone into standards unimaginable a few years ago. Many users are oblivious to the really good backup software that comes with latest windows (vista onwards) and is smoothly integrated in the filesystem. Just use the Start menu and search for backup and you will find the backup and restore control panel. Use an external hard disk for safe keeping of your documents and pictures and whatnot. Once you setup which folders you want to keep, you just need to remember to do a backup once in a while (I do once a week but others prefer daily backups).

Whereas backup keeps track of your data files, restore points keep safe your system settings (whatever makes windows run smoothly). You can create manual restore points using the backup applet mentioned above, or most usually you can take advantage of automatic restore points created by windows updates. What is little known is that these restore points actually create an image of your whole C:\ root partition with minimum impact on your system, using the Volume Shadow Copy service (VSS).

You can access older versions of your files very easily using the property page of files and folders, using the Previous versions tab (see picture). For a file, you get a list of previous versions, as the file used to be at the time a backup was taken. (Unfortunately the GUI isn't very helpful if you want to examine the contents of the file from the backup store, some drag-drop would have helped). The equivalent property page for a folder reflects the restore points saved. For folders the system offers you an easy way to examine the past data, clicking on Open button. For a party trick, right click on a past version of a folder and examine its properties from the menu (that's the last picture to the far right). What on earth is this path? \\localhost\C$\@GMT-2013.03.16-17.10.18\Users\god\Documents\mine\source\craktrak\installer previous versions for files and folders

Access individual files from restore points

This quirky path reflects how VSS offers access to past restore points (notice the @GMT-2013... date part of the path). There is no real filesystem path with this name but if you paste it in the xplorer² addressbar you will find that the old folder version behaves just like a real folder! (you must try this with a folder on your system obviously). Try it out: in a dual pane, have the live folder on one side and the history folder to the other. You can make changes to the live files without affecting the past versions. I can't imagine the amount of work that went in to furnish such smooth behavior at the filesystem level, but hats off to microsoft programmers.

Is this just pointless curiosity? Not quite! Let's say you accidentally deleted an important document. You can't find it in the recycle bin; if you must install a separate program like recuva at this time, chances are you will destroy the precious data blocks. Here's what to do: right click on the folder that contained the deleted file, and see if there are any previous versions available. If a recent one exists (each time windows or microsoft security essentials auto-update you get a free restore point), then open it and use drag-drop to undelete and recover the file!

Win8: C - Nonsense in BASIC

VSS and previous versions work in windows vista and later. VSS still exists in windows 8 but someone saw fit to remove the previous versions GUI from file and folder property sheets. The redmond area must have been aerially sprayed with something dodgy recently. The new way to do it is to use file history (aka time machine) but that requires an external device to be connected all the time. This makes sense in terms of data security, but you lose the plain no-fuss undelete mode I just mentioned.

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