9

Possible Duplicate:
Securely erasing all data from a hard drive

I'm going to give my HDD away, so I'm writing it full of crap so there is no possibility to recover any of my files I had there. Although, I have heard even re-written drives can be recovered some data from them, but I don't consider a high tech guys ever touching it, unless its very easy? I would like to know if it's possible... and how many times I need to write it over?

On the real question here; could it be possible to write into the multiple disks inside the HDD simultaneously and thus increasing total data write rate? So lets say if there are 6 disks inside, I could get 6x write speed if I wrote the same data to each one of them at same time.

Any other suggestions are welcome, since I am writing with 22MB/s speed ATM (old drive, or crappy code?), this will take a while.

Edit: For a security note, my HDD is around 10 years old, or less, and 60GB in size. Does this need only one wipe?

Community
  • 1
Rookie
  • 1,243

6 Answers6

14

I used CCleaner a few times, which is a free tool that does the job. enter image description here

oleksii
  • 850
11

You should use DBAN or similar tools.

SLaks
  • 8,024
7

Just fill it with zero bytes, on Linux with something like

dd if=/dev/zero of=/dev/sdb bs=1M count=1000

this is enough for most purposes and is the fastest thing available.

(there is probably an equivalent on your system, and you could boot a live-boot CDROM linux to run it otherwise)

Of course, if you had military grade secrets on the disk, and/or you are afraid of the CIA, it is probably not enough. (In that case, destroy physically your disk).

Basile Starynkevitch
  • 1,176
4

sdelete - there is really no need for any of those multiple overwrite DoD stuff anymore

edit: sdelete is written by microsoft, it 'knows' about NTFS hidden regions, out-of-band data and all the other fun little features. It requires no install and is quick and easy.

The Mil Spec 'you must overwrite exactly 37 times with random data in the following order' stuff is mostly security app marketing and half remembered DoD requirements. It was argueably necessary on early bit-for-bit and even MFM hard drives where you had a chance of recovering partial zones if you read it under an EM. Although in practice it was more to do with wandering heads that often left earlier tracks entirely intact. With modern GMR hard drives the main concern is the firmware mapping out bad sectors leaving valid data that the OS doesn't know about.

Martin Beckett
  • 10,805
1

Use a Linux LiveCD to run something like

dd if=/dev/urandom of=/dev/sda1 bs=1M

That way you can be sure that you're overwriting everything in the partition and not just the free space. If you're ultra-paranoid you can also run it multiple times, but unless you're sending a disk which formerly had military secrets to someone with ties to foreign governments you probably don't have to worry.

fluffy
  • 658
1

Linux has a standard tool called shred which overwrites a file (or drive) several times with random data, to prevent retrieval of deleted files. If you don't want anyone to know you've used shred, there is an option to overwrite everything with zeroes in the last pass.

To use shred on a disk, find out what it's called (usually something like /dev/hda or /dev/sdc). Then open a terminal and run:

shred -vfz -n 10 /dev/hda

Where /dev/hda is replaced by whatever is the device's name. This will overwrite the entire disk ten times and one last time with all zeroes.

evilcandybag
  • 191