7 passes erasing and data recovering

Discussion in 'Mac Basics and Help' started by jujucaster, Sep 7, 2008.

  1. jujucaster macrumors newbie

    Joined:
    Sep 7, 2008
    #1
    Hi,
    I had kernel panic problems with my mac pro and brought it back to the shop where I bought it.
    Before doing so, I erased the hard drive using the 7 passes method.
    I got back my computer and found in the trash a video I had before erasing.
    I'm wondering how just a simple video survived the 7 passes and if they used a program to recover erased data wich would be absolutely fraudulent.
    Is there a way to find out if a recovering has been done?
    Thank you.
     
  2. misterredman macrumors 6502a

    misterredman

    Joined:
    Oct 3, 2007
    #2
    Are you sure you did erase the whole hard drive by booting from the install discs? Or you erased the free space only?

    I really see no reason why they would bother recovering data from the drive for free.
     
  3. jujucaster thread starter macrumors newbie

    Joined:
    Sep 7, 2008
    #3
    I'm maybe a bit paranoid but that is a very private video and I'm thinking of a guy working on computers and recovering data from people's computer in the hope of finding something interesting...
    Have you heard of all those private sex videos on internet?....
    There are thousands on the net, who knows where they come from?

    Anyway, I erased the drive from the cd and it took the whole 9 hours it usually takes.
    On another forum a guy told me it could come from an external hd that I plugged into my mac. Yes I did plug my lacie yesterday when I got my mac back...
    I just wonder why a file could go into the trash from my ext. hd when I plug it...
    What do you say?
     
  4. sushi Moderator emeritus

    sushi

    Joined:
    Jul 19, 2002
    Location:
    キャンプスワ&#
    #4
    The way that the Mac OS works, is that when a file has been moved to the trash can, it still belongs to the device/volume that it came from.

    So let's say you have external HD named Alpha. On Alpha you delete a file called George. Now George shows up in the trash can (move the file to the desktop trash can). You unmount the external HD named Alpha. George no longer shows up in the trash can. In this case, let's say there were no other files in the trash can so it now looks empty. Now you reconnect your external HD and viola, George now appears in the trash can.
     
  5. jujucaster thread starter macrumors newbie

    Joined:
    Sep 7, 2008
    #5
    That sounds pretty clear to me.
    George really scared me today!
    Thanks for the lesson my friend.
    Greetings from France.:)
     
  6. sushi Moderator emeritus

    sushi

    Joined:
    Jul 19, 2002
    Location:
    キャンプスワ&#
    #6
    You're welcome.

    In this case, was the file concerned on your external HD?
     
  7. misterredman macrumors 6502a

    misterredman

    Joined:
    Oct 3, 2007
    #7
    I am also glad it was not an issue with the erasing... I often rely on that function!
     
  8. iHateMacs macrumors 6502a

    iHateMacs

    Joined:
    Aug 13, 2008
    Location:
    Coventry, UK
    #8
    That is very interesting. I just tried it using a USB flash device. When unmounting the device, the trashcan appears empty. When plugging it back in hey presto the trashcan has the deleted file in.

    I think that would have confused me somewhat if I had not read the behaviour here first :)

    Thanks
     
  9. ChrisA macrumors G4

    Joined:
    Jan 5, 2006
    Location:
    Redondo Beach, California
    #9
    If you every get confused do a right click "get info" on the file in the trash. Then you will see where the file really is. Had the OP done this or loked at the file in the terminal he would have figured out the file was not on the erased drive
     

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