How does Time Machine actually work?

Shredder- said:

I'm about to buy an SSD for my MBP 13" late 2011.

I backed up my entire macbook to Time Machine using an external HDD.
Thing is, I accidentally dropped my HDD and it wouldn't show in "Finder" as a device, only through Disk Utility.
However, I formatted the HDD and lost everything on the harddrive. My question is: Can I put everything back on the HDD through Time Machine? I had some data on that HDD that I'd like to get back.. did it save through time machine?

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When you say you lost everything on the hard drive, assuming your Time Machine backup was there then those files you want are now gone. You can pay one of those computer forensics services to try to recover the files or just live without them. There is some software available that allegedly finds deleted or lost files. I believe that's a feature available in the new pay version of tech tools pro and I believe that feature came with Drive Genius. I have a copy of drive genius I bought when I got my first Mac and I never took it out of the shrink wrap. I don't think I could even run it now as it's probably a PPC executable.

Of course you can put everything back using Time Machine but my question is this: Why not buy yourself a known good USB or firewire drive rather than using the one you dropped? To me this is the most urgent task you have at hand, buying a known good drive so you can make yourself a good backup. You can always use the one you dropped as a "spare" but by no means should it be your only backup.

Time machine just makes a backup of your computer on another device. It will keep all revisions of every file until the destination runs out of space. Then it starts removing the oldest revisions.

If you formatted that hard drive storing the Time Machine backup. Then everything that was on it was lost. There is a chance to recover something with data recovery software if you haven't started backing up to it again. If you have backed up to it again then chances are likely slim to none that you will recover anything useful.

Also if dropping the drive caused damage where it wasn't working right until reformatted. There is no telling how damaged the drive is. After such an occurrence there is no way I would ever use a drive that may be damaged again to store data of any importance. I'd throw it out and replace it.