Erase ext. hard drive securely before sale - recommendations?

Discussion in 'Mac Apps and Mac App Store' started by Dowjohnny, Aug 27, 2014.

  1. Dowjohnny macrumors 6502

    Dowjohnny

    Joined:
    Jul 5, 2011
    Location:
    Germany
    #1
    Hi everybody

    i'm looking to sell two of my older trekstor external hard drives (no SSD). Of course i do not want the buyer to be able to recover my data (even after formatting the drives before sale). There has been no real "sensitive" information on them but it just would give me a better feeling.

    Can anyone recommend a good way to do so? Especially any software tools for mac? I've looked through some google results but found mostly windows based software with very bad reviews etc.. What i've learned is to use a eraser program that overwrites the drives several times instead of just deleting them..

    Any help is appreciated =)

    regards
    Dowjohnny
     
  2. Dowjohnny thread starter macrumors 6502

    Dowjohnny

    Joined:
    Jul 5, 2011
    Location:
    Germany
    #3
    Wow thanks, it didn't come to my mind to check the built in options on my mac :D As always Apple has thought about everything ;)

    Thank you! I think i'll go with the 7pass since it is not an SSD so no increased wear to the drive!
     
  3. maflynn Moderator

    maflynn

    Staff Member

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    May 3, 2009
    Location:
    Boston
    #4
    Agree with the other poster, just go with what apple provided, i.e., Disk Utility :)

    The 7 pass erase will take a long time so be prepared to let the puppy run for a while.
     
  4. Mr. Retrofire macrumors 601

    Mr. Retrofire

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    Location:
    www.emiliana.cl/en
    #5
    Is this really necessary? One pass (zeroes) is not enough!?
     
  5. maflynn Moderator

    maflynn

    Staff Member

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    #6
    I'm usually happy with that, but if the OP wants more peace of mind (and many people seem to do this) the 7 pass will certainly do it.
     
  6. jeremysteele, Aug 27, 2014
    Last edited: Aug 27, 2014

    jeremysteele macrumors 6502

    Joined:
    Jul 13, 2011
    #7
    One is enough. Studies have been shown that one pass (full zeroes) makes essentially impossible (unless you have access to better equipment than an electron-microscope) for anyone to read any actual chunks of data off a magnetic drive (or in the case of an SSD, they include builtin functions for clearing of data).

    Write heads on modern drives are accurate enough that they don't leave anything behind (an issue with previous drives, which (incorrectly) inspired 35-round wipes to be implemented in the 90s and early 00s).

    Although some people are paranoid, so if you want to cause a ton of premature wear (and yes, with magnetic drives - writing over and over causes a TON of wear, mostly due to the heat generated) on your drive - go right ahead with a 7 or 35-round wipe.
     
  7. Dowjohnny thread starter macrumors 6502

    Dowjohnny

    Joined:
    Jul 5, 2011
    Location:
    Germany
    #8
    Well thanks for that education, i thought the wear was only an issue of SSDs but in this case maybe a single run is really enough. Especially since there is no important data on the drive!

    Thanks for all your help
     
  8. maflynn Moderator

    maflynn

    Staff Member

    Joined:
    May 3, 2009
    Location:
    Boston
    #9
    I think a seven pass zeroing will cause negligible wear and tear on your hard drive. I do think its over kill but I don't think you'll prematurely wear out the hard drive because of that. SSDs is different, you definitely don't want to do a 7 pass on those
     
  9. barkmonster macrumors 68020

    barkmonster

    Joined:
    Dec 3, 2001
    Location:
    Lancashire
    #10
    A single pass zero will also expose any damage to the drive you may not even be aware of so I'd do it before selling just make sure it still actually functions. I have various drives from older Macs I keep around for backup and the drives that survived a zero formatting are still usable even now. The odd thing was, a 6Gb ATA drive from a 17 year old Mac works perfectly, a 40Gb ATA drive from a 12 year old Mac was a dud after zeroing.
     

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