An unbiased shopper for a textbook on computer organization might put this tome back on the shelf due to its boring cover, but that would be a mistake. The writing style is lively, and the authors’ enthusiasm shines through. The subject matter is more comprehensive than the title implies, and the presentation is logically organized. An attractive feature is the presentation of SIM68, a software simulation of a manageable subset of the MC68000 processor. The software can be acquired free in several ways, including by ftp, which is conveniently discussed in the chapter on computer networking.

The stated goal of the book is to combine computer organization and assembly language programming, typically taught as separate subjects at the college level, in one text. In reality, the authors pack in more material--most of it relevant to these two main topics.

Chapter 1 is a lengthy introduction. It presents the various levels of a computer system and discusses principal design methodologies. It could have been shortened and combined with chapter 2, which introduces number systems and conversion between them, Boolean logic with minimization and normal forms, gate implementation, and combinatorial and sequential circuits.

Chapter 3 discusses principal computer components, such as main memory, the central processor, and secondary storage. It sketches I/O devices and networks and communication. Interestingly, the chapter is written in such a way that the low-level circuits introduced in chapter 2 are not necessary for understanding.

Chapter 4 describes SIM68, a simple fictitious machine that is a subset of the MC68000 processor. The material covers the instruction set, assembly language programming, and memory. Chapter 5 presents the register-level building blocks of a computer, including encoders, multiplexors, and arithmetic logic units (ALUs), and proceeds to show, via hardware block diagrams, how SIM68 could be built out of these components.

Chapter 6 presents a programmer’s view of the MC68000 processor, covering its memory, register files, addressing modes, and machine language. Chapter 7 introduces the full MC68000 assembly language, which is, naturally, strongly related to the assembly language of SIM68. More advanced topics of MC68000 programming in assembler are covered next. Chapter 8 discusses subroutine calls, parameter passing, stacks, and recursive calls and returns. Chapter 9 presents a good coverage of internal and external exceptions.

Chapter 10 covers I/O--a topic that is all too often omitted from textbooks--and differentiates programmed I/O, interrupt-driven I/O, and DMA. It then presents the memory hierarchy in more detail and gives special consideration to multiprocessing. Finally, chapter 11 offers a thorough yet condensed summary of computer networking.

No book is perfect. The shortcomings of this one are small and harmless. The authors should have used a more direct writing style, eliminating superfluous introductory clauses. The politically correct “he or she” becomes annoying after a while. Finally, some of the low-level electrical engineering subjects could have been omitted. Who cares about transistors, diodes, and inverters when the topic is much closer to computer architecture?

This book is excellent for self-study in computer organization or assembly language programming in general, and for anybody wishing to become familiar with MC68000 assembly programming and the 68000 architecture. Even someone focusing on computer architecture will benefit from this detailed and thorough text. It is also an excellent college textbook for these subjects. The teacher has the rare opportunity to render instruction interesting and lively by using the software offered by the authors. What tends to be dry and abstract otherwise can be touched and felt by programming any topic of interest. Hands-on examples like these motivate students and deepen their understanding.

The book is especially well suited for novices. The authors have the rare gift of introducing new ideas in terms of things we already know from daily life, thus reducing the learning effort. Computer terms are defined before use, no forward references confuse the novice, and low-level and potentially puzzling notions are explained well. Several fairly advanced subjects, including the operating system’s dispatcher, interrupt handling, nested interrupts, and the seven-layer ISO/OSI interconnection protocol, are made to seem easy. The choice of references is exquisite without being exhaustive. The authors have filtered the material for the reader.

The section on CPU design is particularly inspiring. It provides sufficient detail to be interesting, and omits enough to avoid intimidating the reader. Naturally, the 68000 CPU is emphasized. The authors take great care in explaining the numerous addressing methods. The diverse instructions are presented in a well-organized way; related topics are grouped together. The coverage of stacks, call-return, activation record, and recursive linkage is complete, lucid, and presented interestingly.

This book is fun to read and can be attacked from different angles of interest, each time omitting material that is not the focus of the reader’s curiosity. I am convinced the book will see several printings, giving the copy editor the opportunity to correct typos and eliminate repeated words. Reviewing it was a pleasure and time well invested.