Any better ways to ensure that deleted files are non recoverable?

Discussion in 'macOS' started by derekmcwilliams, May 4, 2006.

  1. derekmcwilliams macrumors newbie

    Jun 30, 2004
    In the UK
    Hello guys,

    I'm preparing to sell my 17" G4 Powerbook to a friend but Im not going to reinstall the OS - theres some software on there that Ive bought off the internet but since lost the installer / serials etc.

    Id like to ensure that all the files that I have deleted, some deleted not using the 'secure trash' method are non-recoverable - and I dont know of the best way to do so...

    So... I did the following: while true; do cat sometextfilewithrandomtextin >>/testfile done ... and just waited for my disk to fill up and then rm'd the file... it's VERY crude but also quick.

    For all of those that really know the guts of Mac FS (HFS is it?), should this be sufficient?

    Thanks in advance...
  2. wordmunger macrumors 603


    Sep 3, 2003
    North Carolina
    It sounds like that would work, but if you really want to be sure, I'd get something like drive genius, which can check your drive for file fragments and securely delete them. I guess it's a question of whether you trust your friend, or whether it's worth $99 to be sure.
  3. Mitthrawnuruodo Moderator emeritus


    Mar 10, 2004
    Bergen, Norway
  4. derekmcwilliams thread starter macrumors newbie

    Jun 30, 2004
    In the UK
    Yep, its just like me to overlook the things right under my nose..

    ..theres my feet.

  5. janey macrumors 603


    Dec 20, 2002
    sunny los angeles
    try cat /dev/random next time haha.

    Or, the better way, remove the drive altogether and replace it with a new one (if that's an option).

    Odds are though, your friend won't care enough/doesn't know enough to get the data back even after just a cursory erase.
  6. ChrisA macrumors G4

    Jan 5, 2006
    Redondo Beach, California
    That would likey easae it but there is stil a chance of some data recovry. For example the swap space would not be erased and there might be some data that was held in RAM once still in not yet overwritten swap.
    There are caches and temp files that you may not have found and deleted. You can't know if you got them all

    Around here when a disk once held clasified data theyhave a way of deleting it -- they disasseble the drive, remove the platters then physically destroy them. Nothing short of this can have 100% provable certainty.
  7. mmcxiiad macrumors 6502

    Jul 19, 2002
    zeroing the data out when you format makes the restoration of data more difficult. imagine data recovery like layers. the more times you write over that part of the drive the harder it is to restore it. this can also be done in disk utility.... but fyi - the process isn't quick.

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