This book is intended not to teach the reader how to program the IBM PC family of microcomputers in any particular language, but to help the application programmer master the principles specific to those computers. It focuses on the software support supplied as part of the ROM BIOS (Basic Input/Output System) or DOS. A few chapters deal with hardware basics, such as disk formats and video options, but they support the discussion of the software and give some insight into the design choices that were made.

The examples are usually short; most are written in assembly language since the services supplied by the ROM BIOS and DOS are invoked via an INT (software interrupt) instruction with the required parameters in registers. A chapter supplies highlights of the assembly language for readers who are unfamiliar with the Intel 8086 family of microcomputers (the CPUs of the IBM PC and PS/2).

Topic chapters cover the ROM BIOS services (divided into video, disk, keyboard, and miscellaneous). A summary chapter describes them in both a short form (interrupt number, function number, and a three- or four-word description) and a long form (which adds input and output parameters to the short form).

The book covers DOS from version 1 to version 3 and indicates where an earlier version’s functions have been superseded by a later version. DOS is also summarized in a chapter similar to that for the ROM BIOS.

The book has cross-references for related topics and superseded functions. The authors also indicate where further details may be found in the IBM manuals for complicated subjects such as device drivers.

The index will help the reader find specific information on a topic. Once found, this material is very readable. Tables of contents appear at the beginning of each chapter rather than at the front of the book.