Starting from the idea that operating systems should be taught in a practical way that attempts to get students actively involved in the concrete design and implementation of a complete system, the authors present a basic pattern for the development of a real operating system. This pattern includes a description of the main concepts and a guideline for the systematic realization of the components together with their interaction in a final configuration. The authors illustrate the development by means of PC-XINU, a UNIX-like operating system that was originally written for an LSI-11 and later ported to an Intel 8088 in an improved and extended version. (The folklore includes versions of XINU, written by students, for other processors.) PC-XINU has about 8K lines of code (mostly C with some assembler) and can be obtained from the authors for a moderate price ($79.95). The authors assume that most students have ready access to an MS-DOS PC on which to run the system for exercises. The book is aimed at advanced undergraduates or graduate students.

As in the first edition (published in 1983), the first part of the text (chapters 1–13) describes a minimal system on which simple applications can be run. The components include storage and processor management, synchronization and communication primitives, terminal I/O, and clock management. The PC is not well suited for multitasking; for compatibility reasons, the authors have chosen to use the usual PC Basic I/O System instead of handling hardware I/O in a direct and more efficient way. Chapters 14–18 are more specifically tuned to the PC in providing, for example, simple window and XINU file management, including an interface to MS-DOS files. Chapters 19 and 20 discuss further system utilities and support for putting PC-XINU on differently configured systems. The authors intend to provide a discussion of networks and the integration of protocol software in volume 2.

The presentation of subjects is rather detailed and straightforward, and the idea of a coherent system development dominates. In several programs, comments would have been helpful. The authors rarely discuss alternatives and options in the design process; they relegate some options to the exercises. More positively, the chapters conclude not only with exercises, most of them practical, but also with some suggestions for further reading. The layout shows great care and experience. The structure of the PC-XINU programmer’s manual follows that of “real UNIX,” as does the denotation of system calls.

This text will be very valuable for an introductory, project-oriented operating systems course. It could also be a good companion text even for more research-oriented instructors.