Book excerpt: Confused about zSeries Mainframes? Need to understand the z/OS operating system - and in a hurry? Then you've just found the book you need.Avoiding technical jargon, this book gives you the basic facts in clear, light-hearted, entertaining English. You'll quickly learn what Mainframes are, what they do, what runs on them, and terms and terminology you need to speak Mainframe-ese.But it's not all technical. There's also invaluable information on the people that work on Mainframes, Mainframe management issues, new Mainframe trends, and other facts that don't seem to be written down anywhere else.Programmers, managers, recruitment consultants, and industry commentators will all find this book their new best friend when trying to understand the Mainframe world.