Operation and Bootstrapping

Abstract

Present day computers are usually delivered complete with very sophisticated programs supplied by the manufacturer to make them easy to use. These programs will usually have been constructed, tested and placed in the memories of the computer by means of the even more sophisticated computers which the manufacturers use for the development and production of software. An average user will treat the computer, together with these inbuilt programs (systems software). as an integrated system, and will never need to know about the underlying hardware characteristics or the system software structure. He will usually execute a simple sequence of switch operations at the time the computer is powered up, which bring the system into full operation, and which he knows as the bootstrap sequence. In this book we are very much concerned with the hardware characteristics and system software structure, thus it is inappropriate to assume the existence of system software. A better starting point for our purposes Is a more primitive system equipped only with a simple means for reading from an external media containing programs. The simplest device which has been used In this connection is a paper tape reader or a teleprinter with a paper tape reader/punch.