Hi All, I have an old computer that I am giving to a friend so I wanted to wipe the drives in preparation for that. The master is 250GB The slave is 1TB. I read a couple articles that suggested using a rescue disk and the shred utility to take care of this.  I also read that shred is not necessary to just write all zero's to the drive. The rescue disk I am using is DVD disk one of CentOS 6.3. I ran shred on the fist drive.  It took 4.5 hours to run 3 shred passes plus 1 that writes zeros to the entire drive. Command : shred -zv /dev/sda  (this was on the master disk) Then I ran : dd if=/dev/zero of=/dev/sda bs=16M In one of the articles it showed the above command with bs=1M Does the size of "bs" matter? Also what about the argument that shred is overkill? Thanks!! Keith ------------------------ Keith Smith