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A comment on John Carmack on expert witnesses and 'non literal' copying. Parent comment

Re:John Carmack on expert witnesses and 'non literal' copying by fulafel on Friday February 03, 2017 @01:29AM (#13558173)
The ATA security erase implementations in SSDs frequently lie, and few people know off the top of their heads what tools/procedure use to get to that command in the first place. Nobody knows how to issue this command or knows if this command works on their drive off the top of their heads.

(OTOH I have researched this issue a few times a year despite rarely personally applying the information, so this Google trail is hardly evidence about anything)

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Re:John Carmack on expert witnesses and 'non literal' copying by rsync on Friday February 03, 2017 @12:53PM (#13561662)
"Nobody knows how to issue this command or knows if this command works on their drive off the top of their heads."

Sure they do.

You overwrite the drive with a known large file and then check the checksum of it.

It doesn't matter what kind of mumbo-jumbo the SSD is doing - it doesn't have phantom-double-capacity hiding in there ... if the (drive sized file) you wrote checksums out, you're done.

And if you're paranoid, do it a few times with different (drive-sized-files). Quick and easy and faster than googling anything.

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Re:John Carmack on expert witnesses and 'non literal' copying by fulafel on Saturday February 04, 2017 @07:20AM (#13566729)
No. See eg. https://www.usenix.org/legacy/events/fast11/tech/full_papers...
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