With an HDD, your operating system can (mostly) directly access bits on the magnetic disks, so you can wipe them by just writing 0 to it over and over (historically, there was a paper saying 7 times would make any bits unrecoverable - this changed as density got higher)
With SSDs, your operating system has very little control over what bits a write is touching, a lot more was moved into the firmware on the flash memory itself
So SSDs need a special command “Secure Erase” to wipe them
It’s worth it to mention that after a single pass it was possible to recover single bits with an electron microscope, but not even a full byte. One pass has always been enough to delete actually meaningful data.
With an HDD, your operating system can (mostly) directly access bits on the magnetic disks, so you can wipe them by just writing 0 to it over and over (historically, there was a paper saying 7 times would make any bits unrecoverable - this changed as density got higher)
With SSDs, your operating system has very little control over what bits a write is touching, a lot more was moved into the firmware on the flash memory itself
So SSDs need a special command “Secure Erase” to wipe them
It’s worth it to mention that after a single pass it was possible to recover single bits with an electron microscope, but not even a full byte. One pass has always been enough to delete actually meaningful data.
Yeah, and as densities have increased, fewer passes have been needed to even do that