Book excerpt: Provides a comprehensive guide to all of the major microprocessor families (8, 16 and 32 bit). The hardware aspects and software implications are described, giving the reader an overall understanding of microcomputer architectures. The internal processor operation of each microprocessor device is presented, followed by descriptions of the instruction set and applications for the device. Software considerations are expanded with descriptions and examples of the main high level programming languages (BASIC, Pascal and C). The book also includes detailed descriptions of the three main operating systems (CP/M, DOS and UNIX) common to the most modern personal computers.