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looking into how to properly erasing data from solid state devices is quite the topic with a different answer from just about every webpage I read. I understand there are issues with wiping data from SSDs due to the efforts of wear leveling, but now I read that eMMC supports TRIM, does that mean that eMMC storage will be just as complicated to data wipe as SSDs are?

  • I can't comment on the actual difficulty of wiping data from the underlying electronics, but I will say this - the only way I would feel secure that data on ANY common storage medium is unrecoverable is if it's ground into a fine powder or completely melted into a liquid (and maybe stirred a bit for good measure). – childofsoong Mar 8 '16 at 19:31
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    @childofsoong - Last time I melted a hard drive, I forgot to stir it, and consequently my friend in data recovery was able to reconstruct my cat videos. – TTT Mar 8 '16 at 22:24
  • @TTT I hope they were good cat videos! – childofsoong Mar 8 '16 at 22:44
  • @childofsoong - Humor aside, what options are there to ground it into powder, melt it, etc while remaining cost effective? – Motivated Dec 27 '18 at 4:11
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I don't believe TRIM has a major effect on memory clearing; it's wear-leveling that's the main issue, as it means the OS could 'overwrite' data while it still exists on the physical media. TRIM is just telling the drive that a certain area isn't needed, and the drive can do what it likes with it.

SATA drives (including SSDs) have the ATA-SE commands, which allow you to tell the drive to delete everything on it, including any 'reserve' areas. Whether this is implemented correctly is another question, though. I don't think eMMC drives have this.

As eMMC drives are generally a single package, it's harder to remove the flash chips (or solder onto the pads directly) and read the flash without going through the controller - this could make it slightly more difficult. It's probable that eMMC controllers have debug modes that allow read-out of the flash, though.

I'd have to agree with childofsoong that you can't be certain that it's all gone without complete destruction.

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  • Is there a definitive list of drives that respect the ATA Secure Erase function/feature? It's my understanding (albeit limited at this stage) that not all vendors may fully implement it as per the standard. – Motivated Dec 27 '18 at 4:09

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