According to peter gutmann method, there are 35 passes of data erasing on a hard disk, that completely destroy the data it has on the hard disk. Peter gutmann mentioned on his paper that according to the modern hard disks, a few passes will be enough to completely destroy the data on the hard disk.
According to bruce schneier algorithm, pass number 1 writes a one, pass number 2 writes a zero, passes number 3-7 writes a random characters.
After reading all that information, I was wondering what will happen when making between 7 to 35 passes on a modern hard disk?