This is a repost of something I just wrote as a comment on OSNews:
Shadow copies, at least in the current Volume Shadow Copy implementation, are most definitely NOT “exactly” the same thing as Time Machine. While VSC is very similar, it’s designed to do snapshots at certain times. This is fine for most restores, but in general, if you modify a document several times, you only have the version at the time of the snapshot. As I understand Time Machine, it does a snapshot at modification time, so you have each modification.
This might seem like a marginal difference, but in reality, it’s anything but trivial. This is a world of difference and nothing like this currently exists in a usable form in the base install of ANY consumer OS today. So while it may not be a new idea, it certainly IS innovation.
Time machine has been around since VMS. It’s nothing new.
Time Machine is NOT like VSC, because it incremement on every mod, not just at intervals. Also, this is the first CONSUMER OS to ship with this feature BY DEFAULT. It doesn’t make it incredible, it just makes it a great feature. I’m not overselling it, I’m just being realistic, nothing out there includes this exact functionality in a desktop OS yet.
While VSC is very similar, it’s designed to do snapshots at certain times. This is fine for most restores, but in general, if you modify a document several times, you only have the version at the time of the snapshot. As I understand Time Machine, it does a snapshot at modification time, so you have each modification.
Then your understanding is inaccurate. According to Apple, it does a backup at a set-time each day… exactly like VSC.