On Mon, Nov 22, 2010 at 2:17 PM, Arthur Bela <jozsi.avadkan@gmail.com> wrote: > HDD#1 > HDD#2 > > I copy files between HDD#1 and HDD#2. > > When i finish, i need a quick "hasing method" - i just want to check, > that the copy was 100% ok. > Comparing the hashes of two files is not enough to be certain that they have identical contents. The only way to be, as you put it, 100% sure is to check byte by byte, which will be much slower than hashing.