Hi Adrian!

Thanks for your input, I have modified the post because it is true that in this case, it is better to use "urandom" because what we want is to fill as fast as possible the disk and "urandom" is much faster than "random" even if it is not "so random".

Using "random" may require waiting for the result as it uses a so-called entropy pool, where random data may not be available at that moment. Instead, "urandom" returns as many bytes as the user requested.