Microprocessor 5

3Changes in the Organization of the Earliest Microcomputers

This final chapter, which provides a partial conclusion to this volume, shows the evolution of the organization of the first microcomputers. From the earliest days of the microprocessor in 1971, there were evaluation boards such as the ones described in the previous chapter. Then, the microcomputer appeared, and the market for them exploded with the second generation (i.e. family version). Since the release of the Personal Computer (PC) in 1981 by IBM (International Business Machines Corporation), which refocused the PC for the business environment, motherboard architecture has not stopped evolving and taking advantage of the progress of integration in the domain of microelectronics. In particular, we saw the rise of the concept of the chipset. First, we will describe a second-generation microcomputer, the Apple II. Then, we will examine the evolution of the PC. The notion of chipset is elaborated. The architecture of modern motherboards is described. This chapter concludes with a discussion of low-level software from the firmware (FW) perspective.

NOTE.– The goal of this chapter is not to exhaustively describe the different architectures as would a specialized text about a particular model. It is to show the progression of architectures, even when focusing on a subsystem or a key feature.

3.1. Apple II

It is not possible to talk about the microcomputer without describing the Apple II as a worthy exemplar or as a support ...