Generate a random file with specific size

It's possible to easily generate a random file with specific size filled differently depending on the needs:

• Fill a 200MB file with zeroesdd if=/dev/zero of=/tmp/file.out bs=1024KB count=200
  
• Fill a 200MB file with random values (longer than zeroes - depending on processor)dd if=/dev/random of=/tmp/file2.out bs=1024KB count=200