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  1. #1
    orion456's Avatar
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    Can you secure erase parts of an SSD?

    Unlike a regular hard drive, an SSD has algorithms to even out the use of the available space. As a result, writes are made all over the disk first, before old cells are reused. This gives you no access to specific areas on the SSD when writing.

    Given that situation, is it possible to secure erase part of and SSD? If so, how?
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  2. #2
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    I haven't seen any soft that allows you to pick parts of SSD to secure erase.
    I know only that there is soft like ccleaner that let you perform cleaning of drive's free space. I won't tell you if it's working exactly like secure erase but it gave me some better results while testing drives.

  3. #3
    Low Profile Senior bing's Avatar
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    I believe it is the ssd controller's responsibility in complying to the official standard ANSI ATA protocol specification which has a special command to initiate the so called "secure" erase.

    Once this command is initiated, the ssd controller is supposed to do a full cleaning at the whole storage space to make it "secured".

    Example from the program Parted Magic (freeware) :

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    The problem is, how exactly the ssd controller did to the each flash storage cell when processing this very specific ATA command is not so publicly or widely documented, I guess this needs an electronic forensic to verify it physically at the nand flash whether the controller really secured the ssd.

  4. #4
    Senior Member Mr Alpha's Avatar
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    Quote Originally Posted by orion456 View Post
    Unlike a regular hard drive, an SSD has algorithms to even out the use of the available space. As a result, writes are made all over the disk first, before old cells are reused. This gives you no access to specific areas on the SSD when writing.

    Given that situation, is it possible to secure erase part of and SSD? If so, how?
    Essentially, that is what TRIM does. Once your TRIM an LBA, provided the SSD isn't buggy, you cannot read the data back, short of ripping out the NAND devices and hooking it up to some fancy hardware. And eve in that case it is quite unlikely you will manage to get enough to make sense of.

  5. #5
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    Quote Originally Posted by orion456 View Post
    Unlike a regular hard drive, an SSD has algorithms to even out the use of the available space. As a result, writes are made all over the disk first, before old cells are reused. This gives you no access to specific areas on the SSD when writing.

    Given that situation, is it possible to secure erase part of and SSD? If so, how?
    Thats not correct unless you think about areas (pages) containing data ?

    Pages on a SSD can have 3 stages -

    1. Valid - The page contains data you want to keep

    2. Invalid - The page contains data you deleted

    3. Erased - The page is ready for writes

    When TRIM and/or Garbage Collector (GC) runs, their only job is to change invalid pages to erased pages.

    Without TRIM/GC, you will eventually run out of erased pages - writes are still possible but much slower, because the SSD controller tell the OS to wait while it creates just enough erased pages to contain the data.
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  6. #6
    orion456's Avatar
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    So as long as you have win7 or linux with TRIM the pages are automatically erased over time?
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  7. #7
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    Quote Originally Posted by orion456 View Post
    So as long as you have win7 or linux with TRIM the pages are automatically erased over time?
    Yes, but only if the SSD supports TRIM
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  8. #8
    orion456's Avatar
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    Quote Originally Posted by Nittenti View Post
    Yes, but only if the SSD supports TRIM
    Otherwise, can you use ccleaner to zero out unused parts of the ssd?
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