The Binary System

Abstract

This book is founded on the belief that a computer scientist should know the intimate details of at least one computer. Experience has shown that this cannot be gained by looking into the computer through hundreds of man years of software, or by starting from circuit diagrams. The interface between these two areas of complex detail is the numeric code used to program the computer and the inbuilt primitive functions of the computer which it controls. Thus this book is mainly concerned with the numeric code or Instruction set of the PDP11 computer, and its use in providing an empty machine with elementary system software to support assembly language programming. However, by way of introduction, this Chapter considers binary number representation and arithmetic. Also, in order to make it easier to understand what is meant by a program, without first understanding the considerable detail of the PDP11, the second Chapter is concerned with a very simple hypothetical computer.