I used to think del *.* would erase a disk....
As I learned later in life, Format works better.
Then in college I learned that Format /u was a safer bet agains 'unformat'.
As I became privy to the tools the industry used, I thought that format /u /mbr was the wisest thing to do.
Then forensics taught me to zero the drive out at best.
I then seen a disgruntled employee 0 out a drive with three passes and my Director called up a friend that emailed him an 84K application that recovered the data.
Impressed I was.... ( He would not let me have a copy of the app )
So, the last job that I bailed out of, I 0'ed it out 7 times over before I rolled.
A contact that still worked there said that the company bought three different pieces of
software to try and recover my drive. Curiosity killed the cat? I guess so, the only reason they had to recover my drive was that they did not know what was on it. The funny thing was that there was an image of my drive on the network. They just did not bother to ask me about it when they rushed me out the door the day before the end of my two weeks notice.