I know secure erase refers to SSDs, but I'm asking about spinning rust here.
Lots of programs out there are able to do this sort of thing. I usually use CCleaner. My question is about the overwriting complexity. For instance, I have four options. 1, 3, 7, and 35. Each number refers to the number of times the drive gets overwritten by random 0s and 1s.
Why would you want to write the drive over more than once? Wouldn't the first time fill all the writable sectors and eliminate previous data?
The first pass overwrites everything yes, but the old data can still be read by some programs that are meant to snoop around on the disk. A trace of the old data can be read sometimes after 4 to 5 re-writes. When it gets to truly overwriting your usually looking at 10 times, if not going full out neodymium magnets on either side of the drive to really make sure its clean. Seriously, a lot of companies will use the neodymium magnets thing when it comes to user data on a drive that they are re-purposing or reusing.
I just don't understand how there would be anything left after a couple of re-writes. Is it like residue on a dish or something?
Think of it like a neighborhood that's had houses knocked down.
Everything is 0, but you can still tell where the 1's used to be.
A forensic lab designed for data recovery, may be able to remove and analyse the platters and getting passed an "all zeros" format and maybe a random pattern format. But I think if a drive needs more than 3 random write passes before you feel safe - then you should just hit the drive with a hammer, scratch the surfaces, and melt it in a furnace.
Basically this.
best way to erase HDD
But will it blend?
yes, oh yes
Hammer or a drill works wonders. But the reason of rewriting over the disk is really trying to get the disks back to storing only 0 where there isn't any magnetism. Think of a piece of paper and writing a note in pencil. When you erase it, its still pretty visible what you wrote. By writing over it again and again then erasing it, the original message is pretty much impossible to recover. (least that's how I like to explain it)
Goddamn ancient spinning rust problematic crap. It's been around since 1959 in one form or the other. It is time for it to bugger off to obscurity. I mean... who uses freaking MAGNETS to write data anymore?
Run triple overwrite with random data, reformat in diskpart, open with torqs drivers, remove platters, return to fires of mount doom from whence they came.
I have a few 4TB drives, functioning perfectly, I don't think I want to destroy them, not just yet.
well hammers and drills are ok if you got a lot of time on your hands. if not this might be a better way
also hard drives have a shelf life that varies from drive to drive but it's pretty big. the way hard drives work is they physically write a 1 or a 0 on the disk with a laser. the more time you do this the more worn out the drive gets until you can no longer read it. overwriting works by "scratching" that spot over and over until it's near impossible to figure out what it originally was. the more you do this the harder it is to recover, but the more you do this the more you wear out the drive in that specific spot.
TL;DR
if you want something gone forever and unrecoverable it's going to reduce the lifespan of the drive. you can also just wipe it a few times then let nature (normal use) take it's course rewriting it slowly.
If you're not planning on throwing the disk out then you should encrypt the data, when you want to wipe it just scramble the key and write over it. No one's going to be recovering that and you don't have to wait for a milti-pass format.
Ultimately it depends how valuable the data is and who is likely to try to recover it. If it's just some random the a couple of format passes will do the job. If you're expecting someone to take it to a lab and examine it with an electron microscope you need to format it, degaus it, shred it and burn it.
+1 thats my method.. Encrypt scramble erase
If you want to re-use the drive, read above posts.
If you want a truly effective method to destroy the data on the disk there are several options in order of labour intensity:
Feel free to suggest some more options ;-)
Secure erase isn't an ssd thing but an ATA standard. On ssds it will reset every part of memory to factory defaults erasing the contents, some drives use encryption in which case it will make a new encryption key and throw the old one away.
Some drives will only renew the encryption key and not reset the data which isn't ideal.
On hard drives the same commands work with similar results. Though I'm not sure of hard drives with built in encryption exist?
Secure erase on HDDs will write over the drive and enhanced sexure erase will write a preset of data over the drive . the different is the secure erase functionality is done on the disk controller and will write over all sectors even those not reported to the OS so its theoretically a better option than older erasing processes.
Hard drives the 'standard' is to erase multiple times in case some data is recoverable on the magnetic storage but if this is an actual problem on modern HDDs is debatable. Other magnetic storage such as tape does suffer from that problem.
Edit. Hdparm is the tool to use for secure erase
10/10 loled