OT: Can Reformatting A Hard Drive To ext3 Destroy All the Data On It?

[Robert L Cochran]

I have a hard drive that I need to destroy the data on. What is the most 
dependable way to do this? Can reformatting the drive as ext3 or ext4 or 
some other filesystem effectively destroy the existing data?

Is there free software that can write zeroes or some form of nonsense to 
every storage location?

Thanks

Bob Cochran