Generally what happens when a drive is formatted? I'd think just reformatting and reinstalling an OS ontop of it should suffice..
*shrug* Maybe they just leave the garbage data left over from the last install there and rebuild the FS Tree.
There's always slack space between files and stuff where bits and pieces of data can be recovered. When a drive is formatted, it builds the filesystem structure, which doesn't overwrite every bit of data.
Also, depending on the sensitivity of the data, a single over-write doesn't always suffice. Overwritten data can be recovered with advanced technology. Usually nothing to worry about, but like I said it depends on the sensitivity of the data. The Canadian military (RCMP) recommend 3 overwrites for unclassified/secret data and for top-secret the drive has to be incinerated.
That's what happens during a "quick" format on Windows. I believe the standard option fills the disk with random data, but I'm unsure.
On Linux, you'd simply have to run the shred program after creating the partition.
I'm not positive, but I'm pretty sure a quick format and slow format write the same data to the drive, but a slow format also verifies the drive's integrity.
'shred' isn't designed to shred a partition, just a file (although Linux treats everything as a file, so it's possible). To shred a single partition you can just write random data to it (cat /dev/urandom > /dev/hda1). Or to shred the whole disk you can pipe data straight to the disk (cat /dev/urandom > /dev/hda). That's basically what DBAN does.
