A nuked/wiped HDD, vs. a reformatted HDD. What's the difference?

[Brad Johnson]

Which would leave 99% or more of the data restorable by a competent restoration service.

If memory serves, the MS-DOS format command overwrote every sector, killing any intact data and restoring the drive to zero-state status.  I think that changed with the advent of a DOS client within Windows.  My guess would be it was to save time as drives became larger and larger.

Brad

[Firethorn]

If memory serves, the MS-DOS format command overwrote every sector, killing any intact data and restoring the drive to zero-state status.  I think that changed with the advent of a DOS client within Windows.  My guess would be it was to save time as drives became larger and larger.

Your memory is incorrect.  Even back then, most formats are 'quick' by default - only deleting the file tables.  The data was still fully intact.  Even a 'FULL' format only redoes the formating - redoing the markers and such for file placement.  Thing is, the markers tend to go where the old markers were.

It takes an actually 'wipe' program to overwrite EVERYTHING, though copying large files multiple times can also do a decent job(IE you copy said non-sensitive file until the HD is full, delete them all and start again).

[Brad Johnson]

(IE you copy said non-sensitive file until the HD is full, delete them all and start again).

But what if the file is sensitive and gets its feeling hurt?

Brad

[Zardozimo Oprah Bannedalas]

But what if the file is sensitive and gets its feeling hurt?

Brad

Not my problem. The file should've used Preparation H.

[Perd Hapley]

Operation Yukify fistful Post's strikes again. 

[Hawkmoon]

DoD (Department of Defense) Wipe is what we're looking for. Secure enough to fend of even the average hacker. Lots of freeware utilities out there for doing it.

http://dod-wipe.qarchive.org/

[Phyphor]

Writing 0 to every track and sector, including the Boot Sector and Partition Table is much more secure than a simple "Format C:".

Short of degaussing, that's your best bet to ensure a clean hard drive. 

Heh, You could totally waste a all the data on a HD in MS-DOS with a simple batch file.

@echo off
:begin
echo BLABLABLABLABLA > crap.txt
goto begin


You could do a little more trickery and make it actually echo 'real' zeros to the file, but for the most part, just overwriting everything with garbage was good enough.

(Not for a government standard wipe, but who the hell cares?)