So should a megabyte be 1012 * 1012 = 1024144 bytes or (1000 * 1000 + 1024 * 1024) / 2 = 1024288 bytes?

Perhaps we can simplify this compromise and have a kilobyte as 1024 bytes, a megabyte as 1024000 bytes, a gigabyte as 1048576000 bytes and a terabyte as 1048576000000 bytes.