Ever heard of Petabyte? Or, for that matter, Exabyte? If you haven’t, then you are going to hear a lot about them in the future. And, that’s not all. Very soon, a new word, Zettabyte, is going to make it into our glossary. Now don’t scratch your heads. We will explain. These are all terminologies pertaining to online data transfer. They are used to describe disk space, or data storage space, and system memory.