Proper deletion should include writing all 1s or all zeroes to the block but y’all be lazy as fuck.
Comment on iPhone owners say the latest iOS update is resurfacing deleted nudes
cyrus@sopuli.xyz 5 months agoI mean, to be completely fair, that’s how data storage works.
We cannot really just make data disappear, so we let it get overwritten instead
Forester@yiffit.net 5 months ago
cm0002@lemmy.world 5 months ago
Only necessary on the ol spinning rust, with SSDs not only is not completely unnecessary, but it also burns extra writes.
Spinny’s store data magnetically on the platter with 1s and 0s, SSDs store data on the NAND as a held charge. If there’s a charge in the block it’s a 1 if there’s no charge it’s a 0.
With spinny’s, a file gets marked as “deleted” but the residual magnetic 1s and 0s will remain on the platter until eventually overwritten
With SSDs a file gets marked “deleted” and within no more than a few minutes TRIM comes along and ensures the charge on the NAND is released for that data, there’s no residuals to worry about like with spinny’s and is in fact necessary to ensure decent lifespans.
Drummyralf@lemmy.world 5 months ago
I want a spinny as a pet now. Sounds cute.
Verat@sh.itjust.works 5 months ago
But wouldn’t TRIM be the deleting he is requesting? Removing the charges would be setting all the bits in that block to the same value.
EvilBit@lemmy.world 5 months ago
I’m not an expert, but wouldn’t proper deletion be writing random ones and zeroes to the block?
catloaf@lemm.ee 5 months ago
I don’t think it’s been shown to make a difference.
EvilBit@lemmy.world 5 months ago
It certainly feels more deleted…
AProfessional@lemmy.world 5 months ago
That just makes no sense to do, modern storage is write limited. As long as you used encryption the old bits mean nothing.
catloaf@lemm.ee 5 months ago
SSDs are. Big storage is not using SSDs.
cyrus@sopuli.xyz 5 months ago
yeah cuz for normal, day-to-day use that’s exponentially slower the more you’re deleting
You can do that when you wipe something.
Forester@yiffit.net 5 months ago
Yeah, such as sensitive photos
foggy@lemmy.world 5 months ago
Nitpick: it should be fuzzed with random 0s and 1s.
lurch@sh.itjust.works 5 months ago
the shred command in Linux tries to do this, but it may not work if the hardware moves rewritten data blocks around to mitigate wear.
tal@lemmy.today 5 months ago
shred
doesn’t even necessarily work at the OS level. If you use something likeext3
and I assumeext4
, normally when you overwrite data in a file, you’re not overwriting data even at the logical level in the block device. Journalling entails that you commit data to somewhere else on the disk, then update the metadata atomically to reference the new data.
solarvector@lemmy.zip 5 months ago
That’s skipping over the fact that recovering deleted data, even if it isn’t overwritten, is not an “oops”. It it takes extra effort, and if that data isn’t being protected it would be overwritten incidentally as drives are used.
There is a big difference in a database between “flagging” data and actually removing the association of the data to the database.
pete_the_cat@lemmy.world 5 months ago
The data just needs to be overwritten to be truly deleted.
mojo_raisin@lemmy.world 5 months ago
But clearly the data is not overwritten and this was intentional. How do I know? Because that would amount to a massive amount of data, if it was de to a bug in Apple software or underlying filesystems, it would be detected in monitoring systems “Hey, we’re using 10x the data we should be, maybe we should look into it”.
The mistake was in the flag code that was supposed to fool us.
cyrus@sopuli.xyz 5 months ago
no when I say “overwritten” I mean that the area is set as deleted in the filesystem and the next time something writes to that area the data that was there before is disregarded.
mojo_raisin@lemmy.world 5 months ago
So are you saying that they suffered from a filesystem bug that caused deletion failure? I’d imagine they use standard filesystems on their backend, I haven’t heard about any bugs like this.
If you ask me, what’s more likely, that a company known for shitty behavior lies about deleting files so they can continue to use that information to profit, – OR – that they are experiencing a filesystem bug on their backend, I’ll choose the former.
cyrus@sopuli.xyz 5 months ago
no I don’t believe a damn word of what apple’s gonna say on this, I just wanted to get the message out there that generally file deletion works by allowing data to be overwritten, so if the images are local this could very well just be that either it’s showing data that hasn’t been overwritten yet or it accidentally brought things out of the “recently deleted” depending on how long ago it was deleted.
barsoap@lemm.ee 5 months ago
A single overwrite might not be enough to defeat physical forensics because shadows of the old data persist in how the new data is stored. Also when it comes to SSDs you might be waiting a long time for the data to get overwritten as the drive will wear-level its erm sectors (what are those things called with SSDs?).
kaboom36@ani.social 5 months ago
They are called cells IIRC