Bøger af Heller

This is a reproduction of a book published before 1923. This book may have occasional imperfections such as missing or blurred pages, poor pictures, errant marks, etc. that were either part of the original artifact, or were introduced by the scanning process. We believe this work is culturally important, and despite the imperfections, have elected to bring it back into print as part of our continuing commitment to the preservation of printed works worldwide. We appreciate your understanding of the imperfections in the preservation process, and hope you enjoy this valuable book.

Computers these days spend a fairly low fraction of their time computing. A processor used to be a central processing unit-a set of wires and vacuum tubes, or later a set of printed circuit boards-which was nestled deep within the computer.