KILLDISK, how does it work?

cadcmcr · 12-15-2008, 05:00 PM

Hi, thanks in advance oh masterful tech gurus,

I humbly request ye assistance regarding a very perplexing question...

Long story short, I'm selling my computer to a stranger and don't like the idea of them snooping around my stuff, and I'm suspicious of the 5 second quick format vista does during a fresh install.

So I downloaded KillDisk but could only use the trial version which was just to do a single pass zero-all of the drive. Now my questions is this: Why in the world would I need to do the "German VSITR" or the "Russian GOST" or the seemingly almighty "Gutman" if a Zero-All presumably changes all the 01011101111 stuff to just 00000000000...

So you can see how this is confusing a simpleton such as myself, why do I need some fancy "Gutman" if a zero-all just completely erases everything, I mean how in the heck can anyway recover ANYTHING form all 0000000s ???

Some enlightenment would be greatly appreciated thank you SO MUCH in advance, again!

**raptor_pa** · 12-15-2008, 05:28 PM

Assuming you don't have classified information on your PC, then a single pass 00 overwrite will be nearly as effective. There is no easy or cheap solution to recover the data after a 00 overwrite. For drives coming out of facilities where there is a legal requirement such as banks, medical facilities etc, then multiple passes and a few other tricks might be required. The concern is that track edges can still carry some readable impressions that aren't necessarily flipped in a single pass. A hard drive does not really record a digital 1 or zero in a discrete location, but actually records a more analog type signal that is interpretted as a 1 or 0. Three passes is DOD spec for non-classified information. For classified information the only DOD accepted destruction is physical destruction. It is unlikely that the average person is going to have the hardware required to even attempt a recovery after a single pass, let alone get anything useful LOL And it sure isn't going to happen with $100 software.
You could do multiple passes with KillDisk, or download DBan and do multiples with that. after you are done, Run GetDataBack, R-Studio, Stellar Phoenix or some of the other recovery software against the drive to see that it is clean.
It is possible for wiping software to miss some information, but it is very unusual. It is also possible to get data back from sectors marked in the G-List of the drive. The G-List is the 'grown list' of bad sectors. during normal operations sectors will become bad on a disk, these sectors are added to the g-list and remapped to spare sectors by the drives firmware. Normally these sectors are skipped during data recovery. there are tools out there that will read the g-list and attempt to read data from these sectors, or blank the glist so they can be read. Normally these procedures are reserved for higher end forensic cases. The cheapest I've seen hardware capable of this is around $2000.00 - and it goes way up from there. The bad sectors will usually only return bits and pieces of data, and they get read in the hopes of finding some useful scrap of evidence.

Tumbleweed36 · 12-15-2008, 05:34 PM

Dban is the best for what you want to do. It does take some time to get the job done, but if you Dban it, you don't have to worry about the average "Joe" taking a look at your information. If interested, then here is the link:

Dban Complete Disk Eraser

Please note: Be sure you have all disks unhooked that you do not want formatted and cleaned, because this program while great has the capability to erase multiple disks at one time if hooked to the computer.

12-15-2008, 05:00 PM	#1 (permalink)
cadcmcr Registered User Join Date: Dec 2008 Location: Land of the Lotus Eaters Posts: 4 OS: Vista	KILLDISK, how does it work? Hi, thanks in advance oh masterful tech gurus, I humbly request ye assistance regarding a very perplexing question... Long story short, I'm selling my computer to a stranger and don't like the idea of them snooping around my stuff, and I'm suspicious of the 5 second quick format vista does during a fresh install. So I downloaded KillDisk but could only use the trial version which was just to do a single pass zero-all of the drive. Now my questions is this: Why in the world would I need to do the "German VSITR" or the "Russian GOST" or the seemingly almighty "Gutman" if a Zero-All presumably changes all the 01011101111 stuff to just 00000000000... So you can see how this is confusing a simpleton such as myself, why do I need some fancy "Gutman" if a zero-all just completely erases everything, I mean how in the heck can anyway recover ANYTHING form all 0000000s ??? Some enlightenment would be greatly appreciated thank you SO MUCH in advance, again!

12-15-2008, 05:28 PM	#2 (permalink)
raptor_pa Mod Hardware Team Join Date: Dec 2008 Location: Central PA Posts: 4,518 OS: XP	Re: KILLDISK, how does it work? Assuming you don't have classified information on your PC, then a single pass 00 overwrite will be nearly as effective. There is no easy or cheap solution to recover the data after a 00 overwrite. For drives coming out of facilities where there is a legal requirement such as banks, medical facilities etc, then multiple passes and a few other tricks might be required. The concern is that track edges can still carry some readable impressions that aren't necessarily flipped in a single pass. A hard drive does not really record a digital 1 or zero in a discrete location, but actually records a more analog type signal that is interpretted as a 1 or 0. Three passes is DOD spec for non-classified information. For classified information the only DOD accepted destruction is physical destruction. It is unlikely that the average person is going to have the hardware required to even attempt a recovery after a single pass, let alone get anything useful LOL And it sure isn't going to happen with $100 software. You could do multiple passes with KillDisk, or download DBan and do multiples with that. after you are done, Run GetDataBack, R-Studio, Stellar Phoenix or some of the other recovery software against the drive to see that it is clean. It is possible for wiping software to miss some information, but it is very unusual. It is also possible to get data back from sectors marked in the G-List of the drive. The G-List is the 'grown list' of bad sectors. during normal operations sectors will become bad on a disk, these sectors are added to the g-list and remapped to spare sectors by the drives firmware. Normally these sectors are skipped during data recovery. there are tools out there that will read the g-list and attempt to read data from these sectors, or blank the glist so they can be read. Normally these procedures are reserved for higher end forensic cases. The cheapest I've seen hardware capable of this is around $2000.00 - and it goes way up from there. The bad sectors will usually only return bits and pieces of data, and they get read in the hopes of finding some useful scrap of evidence.

12-15-2008, 05:34 PM	#3 (permalink)
Tumbleweed36 Asst Manager Hardware Join Date: May 2005 Location: USA Posts: 19,460 OS: XP Professional	Re: KILLDISK, how does it work? Dban is the best for what you want to do. It does take some time to get the job done, but if you Dban it, you don't have to worry about the average "Joe" taking a look at your information. If interested, then here is the link: Dban Complete Disk Eraser Please note: Be sure you have all disks unhooked that you do not want formatted and cleaned, because this program while great has the capability to erase multiple disks at one time if hooked to the computer. __________________ ---------- I don't receive email notifications of replies to subscribed threads. (Internet provider policy) Therefore, if I don't respond to your post within 24 hours, please send me a reminder PM and include the link to your thread.