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boersc t1_iy3j0vp wrote

Reply to comment by Persist_and_Resist in eli5 How is computer memory deleted? by unlikemike123

There is also the action of a 'destructive delete', where the file is actually overwritten with gibberish. This is done when you want to delete a file without ever being able to restore it. This could be the case when handling confidential information, or in case you plan to retire the PC and hard disk.

Basically, you're telling the system to do the 'overwriting' action immediately.

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ElAdri1999 t1_iy48082 wrote

But if you can do the hammer delete then it's way better, since someone might be able to recover your stuff if not sufficiently deleted

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[deleted] t1_iy4loxs wrote

[deleted]

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CrazyMando t1_iy4nqq0 wrote

Sledgehammer

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Pikassassin t1_iy4py1y wrote

Gigantic electromagnet

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ElAdri1999 t1_iy4qk5j wrote

All, all is good.

My last dead HDD I removed the magnets(which are fucking strong as fuck btw) and spun the platter while scratching lines on it, when I finished I broke it just for the safety

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Kriss3d t1_iy4tw7s wrote

If it's a 2.5" hard-drive you can just give it a good whack with a hammer.

When it sounds like a box of matches, your data is safely deleted.

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cope413 t1_iy4tl9m wrote

Just make sure none of your crypto is on a drive you do that to.

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yoshhash t1_iy4a8jw wrote

Isn't that the same thing as over writing with the same file name?

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boersc t1_iy4apc9 wrote

Not perse. In that case you're erasing/reusing the ledger entry, but the 'new' file may get written on a wholly different location depending on how the OS works. But yes, it CAN work the same, if the new file overwrites the exact same spot as the old file. Most OSses work that way.

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bob0979 t1_iy4blr4 wrote

Many drive cleaner tools will have a tool to wipe free space. They write over every bit that is not occupied with 'undeleted' data or stuff you're using. They replace everything not in use with new junk data that could just be 00000001 for every bit. This takes a fair bit of time but doing this a couple of times can remove any trace of what a specific bit says or even used to say.

If you save somethinn as 'file.name' and it's contents are 00000111 then delete it, it stays as 00000111, but if you delete it then wipe free space it changes that 00000111 to something useless.

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Grezzo82 t1_iy5aoeu wrote

“A couple” is sometimes not enough, but a few more is considered secure enough for most contexts, though gov will often physically shred the disks to be sure.

I only know for sure with macOS, but I image isn’t this applies to all: the OS has a built in secure erase feature that will overwrite a whole disk enough times to be confident that the data is irrecoverable

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Any-Broccoli-3911 t1_iy4fv5b wrote

No, even if it's the same filename, there's no guarantee that it will be at the same place. Also, if your new file is smaller, for example an empty file, it can only overwrite a tiny part of it if ever it's at the same place.

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graebot t1_iy4q95g wrote

Does that work with SSDs? I thought they try to write in a new location each time to prolong life

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Grezzo82 t1_iy5arcz wrote

SADs are much harder (perhaps impossible) to securely erase, you’re right

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