Book Review: Inside Windows NT

A Few Decades Late Book Reviews

Inside Windows NT, by Helen Custer
Microsoft Press, 1992; 385 pages, ISBN 1-55615-481-X; $24.95

Inside Windows NT was one of the earliest published books about Windows NT, predating the actual July 1993 release of Windows NT 3.1 by several months. Helen Custer joined Microsoft as part of Dave Cutler’s team of ex-DEC engineers; her task was to chronicle the development of NT and describe the new operating system in a way accessible to “the rest of us” (who care about operating systems).

Helen Custer cited Gordon Letwin’s Inside OS/2 as justifying her writing Inside Windows NT. The two books are very different, but share a similar basic concept: Provide a medium-level overview of an operating system without getting bogged down in detail, but clearly describing the system’s philosophy and structure without leaving too many “black boxes”.

The foreword to Inside Windows NT was written by David N. Cutler, the operating system’s chief architect. The foreword reads like Cutler’s autobiography, largely chronicling his work on operating systems at DEC.

The actual book starts with a statement of the NT “mission”—create Microsoft’s operating system for the 1990s. Among the primary objectives for the OS were portability, multiprocessor support and scalability, support for distributed computing, and security.

The second chapter provides a very general overview of NT, its basic structure and architecture. The NT Executive concept is explained here (and the relationship between the Executive and the Kernel).

Chapter 3 is the first with more detail and describes one of the key NT components (and one that sets it apart from most other operating systems), the Object Manager. The discussion also goes into the NT security model, tokens, and access lists.

Chapter four is an OS classic and deals with processes and threads. The next chapter is all about NT subsystems, and starts with explaining how the requirement to support (originally) OS/2 and POSIX APIs more or less forced the NT designers to implement OS “personalities” in the form of subsystems.

Chapter six is another classic and is dedicated to virtual memory. Chapter 7 explains the kernel, including the dispatcher, exception and interrupt handling, and synchronization. Naturally “kernel” is the NT-specific term here and only refers to a specific part of the NT Executive, not the entire part of the OS running with supervisor privileges.

The 8th chapter describes another unique NT component, the frighteningly complex I/O subsystem.  The concept of I/O Requests is explained in detail, and a brief overview of the layered driver model employed by NT is given.

The ninth and final chapter is a relatively brief discussion of a complex topic, NT networking support. By necessity, this chapter is very dense and goes into less detail than several of the preceding chapters.

There is a fairly extensive glossary, a bibliography section, and an index.

Custer’s book is unique because it was written in parallel with the actual OS development, not after the fact. It was the first in-depth book about NT design and architecture available on the market. Inside Windows NT is very useful because it spells out the design goals and some of the architectural decisions made by the team, rather than just describing how NT works. It is certainly not a reference book (but that ground is well covered).

While NT has changed since 1992, Inside Windows NT has a clear historical value, and may even be useful to current developers who wish to understand why certain aspects of NT are the way they are.

Inside Windows NT is very different from G. Pascal Zachary’s Showstopper!, the story of NT’s creation. While Showstopper! is a book written for the general audience and contains minimum of technical detail (and what little there is isn’t always accurate), Inside Windows NT is very much a technical book, created by a technical writer. A computer science degree isn’t required, but a high level of familiarity with computing concepts certainly is. In many ways, the two books are complementary: Showstopper! is the human interest story, and Inside Windows NT is the technical treatise.

Inside Windows NT has a little sibling, a booklet called Inside the Windows NT File System (also by Helen Custer), which concentrates solely on the new NTFS file system.

The second edition of Inside Windows NT was written by David A. Solomon in 1996 and eventually turned into the Windows Internals series, with the 6th edition published in 2012.