As you may or may not know, Windows 8 has scrapped what I thought was one of the killer features of Windows Vista/7, which was "Previous Versions" (aka. VSS - Volume Shadow Copy Service), and have essentially replaced it with something considerably different, File History. I only found this out yesterday after installing Windows 8 and wondering where the "Previous Versions" tab had gone. Then to my horror, I stumbled across this ArsTechnica article: http://arstechnica.com/information-...tep-back-in-time-with-windows-8s-file-history
For me, it was the straw that broke the camels back, and I promptly restored the Windows 7 image I made before installing 8. The ArsTechnica article was good because it shone a critical eye on File History as a replacement for VSS, and did well representing the perspective of the power user. The problem is that Microsoft has replaced a whole-disk in-place versioning technology with a partial off-disk backup tool. They're completed different.
I found it bewildering that Microsoft would essentially throw VSS in the bin, after I was sure it had an even brighter future. I've always been of the opinion that with todays gigantic hard-drives, it should be impossible for a user to lose a file as a result of either their own mistake, or the fault of software. VSS was a step towards that, and as long as you had it enabled on all your storage volumes, it ensured you could never completely lose a file by doing something as easy as overwriting it. I was sure the next logical step for Microsoft would be to not only have VSS enabled by default on all volumes, but to automatically devote all free-space (or at least a large percentage of) to VSS - shadow copies would be deleted as space is consumed. After all, what use is free hard-drive space. It's the same idea as RAM. Free RAM doesn't do anything for performance, so why not populate it with cached data, which is exactly what SuperFetch did.
Instead, Microsoft have taken a step backwards, and now we're left with big hard-drives with free space that goes completed wasted, leaving users vulnerable to losing their valuable data. What perhaps makes this worse, is that "File History" is a trivial technology that any 3rd party vendor could implement - in fact most pay-for backup solutions come with versioning functionality (sure, maybe their interface isn't as pretty, but the data is there). It's akin to replacing UAC or some other low-level security mechanism with Microsoft Defender. The obvious flaw of these backup solutions, including File History, is that they're not differential, and so keeping versions of large and frequently changing files is not practical, and here comes the part I think stings the most: 3rd parties cannot re-implement VSS. VSS is a low level feature built-into the NTFS driver; it needs to be aware of every modification made to the file system.
So what Microsoft have done is taken a huge backwards step in regard to protecting user data. Instead of heading toward a future where losing data is a problem of the past, they've headed in a direction representative of where we were at 10+ years ago.
With VSS, one can maintain backed up and versioned data with only double + 20% of their primary storage. If I had 8TB of data, I can maintain a complete backup of that, with weeks if not months of previous version information, on a 10TB volume. File History, depending on the size of the files you work with, could demand an exponential amount of storage to backup that 8TB of data. If you've got a few big files that change frequently, they'll eat away at the backup space available requiring older versions of smaller files to be removed, further reducing the effectiveness of the versioned backup. That's always been the problem with Time Machine on the Mac.
At the least, Microsoft could of improved on the time machine (file history) idea by implementing reverse differential backups instead of incremental, which would come with similar storage efficiency as VSS. A reverse diff is pretty simple. For every backup, you do a diff on each file that has changed since the most recent backup; you wouldn't even have to read the whole backup file, you could derive what has changed from a checksum of each block/page/megabyte/whatever. The diff is then applied to the backed up file (to save recopying the whole file, preserving bandwidth). What you then do is store the inverse of that diff with the current backup, hence making the diff file your previous version. To load the file as it was 8 versions ago, you apply the 8 most recent reverse diff's to the current most recent backup. The computational heavy operation of rebuilding the old version is only required when you actually want to restore it, so the performance of the backup remains relatively quick. This is a much cleverer way to do backup and versioning, and would work well backing up over low bandwidth such as to the internet. The good thing about reverse diff's is that you don't need to make an initial full-copy and base your diffs off of that. Instead, your most recent backup is always your full copy, so storage efficiency is maximised. Missed opportunity Microsoft!
I don't plan to upgrade to Windows 8 not only for this reason, but for all the other reasons why Windows 8 doesn't make any sense. I'm only praying that Microsoft realise their mistake (as they sometimes do) and bring VSS back as an even better technology package.
Is my assessment of File History fair? I have doubts that I'm seeing the whole picture here as what Microsoft have done just doesn't seem to make any sense. If Microsoft's interpretation of keeping-up-with-the-times and staying agile is making sweeping thoughtless and poorly implemented changes, then I'm bailing.
For me, it was the straw that broke the camels back, and I promptly restored the Windows 7 image I made before installing 8. The ArsTechnica article was good because it shone a critical eye on File History as a replacement for VSS, and did well representing the perspective of the power user. The problem is that Microsoft has replaced a whole-disk in-place versioning technology with a partial off-disk backup tool. They're completed different.
I found it bewildering that Microsoft would essentially throw VSS in the bin, after I was sure it had an even brighter future. I've always been of the opinion that with todays gigantic hard-drives, it should be impossible for a user to lose a file as a result of either their own mistake, or the fault of software. VSS was a step towards that, and as long as you had it enabled on all your storage volumes, it ensured you could never completely lose a file by doing something as easy as overwriting it. I was sure the next logical step for Microsoft would be to not only have VSS enabled by default on all volumes, but to automatically devote all free-space (or at least a large percentage of) to VSS - shadow copies would be deleted as space is consumed. After all, what use is free hard-drive space. It's the same idea as RAM. Free RAM doesn't do anything for performance, so why not populate it with cached data, which is exactly what SuperFetch did.
Instead, Microsoft have taken a step backwards, and now we're left with big hard-drives with free space that goes completed wasted, leaving users vulnerable to losing their valuable data. What perhaps makes this worse, is that "File History" is a trivial technology that any 3rd party vendor could implement - in fact most pay-for backup solutions come with versioning functionality (sure, maybe their interface isn't as pretty, but the data is there). It's akin to replacing UAC or some other low-level security mechanism with Microsoft Defender. The obvious flaw of these backup solutions, including File History, is that they're not differential, and so keeping versions of large and frequently changing files is not practical, and here comes the part I think stings the most: 3rd parties cannot re-implement VSS. VSS is a low level feature built-into the NTFS driver; it needs to be aware of every modification made to the file system.
So what Microsoft have done is taken a huge backwards step in regard to protecting user data. Instead of heading toward a future where losing data is a problem of the past, they've headed in a direction representative of where we were at 10+ years ago.
With VSS, one can maintain backed up and versioned data with only double + 20% of their primary storage. If I had 8TB of data, I can maintain a complete backup of that, with weeks if not months of previous version information, on a 10TB volume. File History, depending on the size of the files you work with, could demand an exponential amount of storage to backup that 8TB of data. If you've got a few big files that change frequently, they'll eat away at the backup space available requiring older versions of smaller files to be removed, further reducing the effectiveness of the versioned backup. That's always been the problem with Time Machine on the Mac.
At the least, Microsoft could of improved on the time machine (file history) idea by implementing reverse differential backups instead of incremental, which would come with similar storage efficiency as VSS. A reverse diff is pretty simple. For every backup, you do a diff on each file that has changed since the most recent backup; you wouldn't even have to read the whole backup file, you could derive what has changed from a checksum of each block/page/megabyte/whatever. The diff is then applied to the backed up file (to save recopying the whole file, preserving bandwidth). What you then do is store the inverse of that diff with the current backup, hence making the diff file your previous version. To load the file as it was 8 versions ago, you apply the 8 most recent reverse diff's to the current most recent backup. The computational heavy operation of rebuilding the old version is only required when you actually want to restore it, so the performance of the backup remains relatively quick. This is a much cleverer way to do backup and versioning, and would work well backing up over low bandwidth such as to the internet. The good thing about reverse diff's is that you don't need to make an initial full-copy and base your diffs off of that. Instead, your most recent backup is always your full copy, so storage efficiency is maximised. Missed opportunity Microsoft!
I don't plan to upgrade to Windows 8 not only for this reason, but for all the other reasons why Windows 8 doesn't make any sense. I'm only praying that Microsoft realise their mistake (as they sometimes do) and bring VSS back as an even better technology package.
Is my assessment of File History fair? I have doubts that I'm seeing the whole picture here as what Microsoft have done just doesn't seem to make any sense. If Microsoft's interpretation of keeping-up-with-the-times and staying agile is making sweeping thoughtless and poorly implemented changes, then I'm bailing.
. It probably doesn't keep versions long enough...
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