Low level format => 7 DoD pass =>2 random pass

[Rapscallion]

Hi all,

I sold some of my hard drives, and before selling them, I did first a win 7 full format, then I came across with eraser and started 35 pass Guttmann, but then I realized that it would take more than a week for a 1 TB (sata 2) portable drive connected via usb 2.0 . Therefore, I cut the process after approximately %10-20 percent. 7 pass DoD seemed much faster, so I did first 7 DoD pass. In the meantime, I saw that there are some low level format tools out there, and I used HDD LLF Low Level Format Tool 4.25 (paid for it) once to perform the so-called low level format, which I believe is just a zeroing of the hard drive. As I do not know much about recoverability options, I did then 2 times pseudo-random overwriting with eraser. I have read some articles saying that the data can still be recovered, and this makes me a bit nervous. Like you do, I am also asking myself why I didn't just crash the hard drive into pieces, but it is no use to think like that now.

I tried to recover my files using some recovery software such as seagate file recovery, undelete plus, recuva, and recover my files (getdata), but only one of them recovered some vp6 encoded vidoes having different names and not playable with splayer-vlc player-flv player and etc. I am not exactly sure, but it was seagate file recovery software that showed those files after deep scanning the whole hard drive, but they were marked as unrecoverable by the software itself. I actually do not know what those videos are. Btw, meta and root files have always been recovered by the aforementioned software, but they did not make sense at all, at least for me.

So I need your comments on whether my way of erasing data was enough or not. Please let me hear your valuable comments. Thanks in advance.

P.s. I never saved the scan results into the same hard drive. I also let the system volume information files to be erased by eraser to be able to remove the cluster tips error. Including heritage or something like that for the administrator made it possible to touch the system volume information files, and I always checked erase cluster tips option, which let eraser finish the erasing of the hdd without any error.

 

[garrett01]

You only need to do a 1 pass erase, this will render any data on the drive useless to the casual observer. To achieve this, format the drive and then do a free space erase.

 

[Rapscallion]

Thank you very much for your reply. There are some people out there claiming that some software are capable of recovering data even if the hard drive had been overwritten more than once. That's why I was curious about what to do. As for the casual observer, do you mean somebody who does not even care to recover my data or somebody who might try to recover the data with the available tools to be easily found on the Internet but without success in recvering process? Thanks in advance.

 

[garrett01]

Casual == most people/tools on the internet. If you were determined it might be possible to infer some data. e.g imagine a data block of 10101010 now one pass erase is supposed to replace each with random strings
10101010 could become 11101110 or equally 10101011 or 11111111 . We are in the realms of statistics here and entropy where some weakness in the random number generator could be exploited over a large amount of data.

 

[pitterlee]

What happens if you manually empty the recycle bin? Also are you the only user of the PC? It could be another user account owns those files.

 

[garrett01]

manually emptying the recycle bin just leaves the files as marked deleted. They can easily be recovered. Freespace erase is designed to solve this.