Erasing a hard drive

[JesseD]

One of the insurance companies I've consulted for recently used active killdisk (here) to kill sensitive data on "important" drives. They ran a 10 cycle kill on it. The free version would have to run 10 times individually.

 

[RogerT]

I've used a product called SureClean for a few years. Hopefully it's
working.

RT

 

[Steve Foley]

What does simply deleting the file do? does it still stay in the hard drive, after emptying the recycle bin?

You can think of the hard drive as a collection of video tapes. When you're done with a tape, you put it in the with the empty tapes, indicating that it can be reused. You don't actually erase the tape, as that will be done the next time you put it in your CR. You can go through your pile of 'blank' tapes to see if there's anything interesting there.

Your hard drive works similarly. When you delete a file, the system simply puts those sectors back in the list of available sectors. It doesn't 'erase' the contents.

 

[TMetzinger]

You can think of the hard drive as a collection of video tapes. When you're done with a tape, you put it in the with the empty tapes, indicating that it can be reused. You don't actually erase the tape, as that will be done the next time you put it in your CR. You can go through your pile of 'blank' tapes to see if there's anything interesting there.

Your hard drive works similarly. When you delete a file, the system simply puts those sectors back in the list of available sectors. It doesn't 'erase' the contents.

Gotta pick a nit here - this "erase or not" decision is NOT made by the disk drive hardware - it's made by the operating system. Certain operating system or file system configurations will in fact overwrite the released disk sectors when a file is moved or deleted.

More common now for security purposes is to completely encrypt the filesystem - and this sometimes IS done by the disk hardware. The good part is if it's done correctly the data is not recoverable without the encryption key by anyone other than nation-states (and few of those). The bad news is that there are a LOT of bad products out there that don't protect the encryption key well, which means that even though the "lock" is robust the system left the key under the doormat.