Two years ago, when I reviewed a portion of the predecessor of this book [1,2], I wrote, “I believe that Digital Press will eventually have a worthy successor to their VAX/VMS Internals book, but for those who can afford to wait until the first revised edition is available towards the end of 1993, I’d recommend doing so.” As with many computer-related projects, the release date for the first revised edition seems to have slipped a bit, but this volume is indeed a worthy successor to the well-known VAX/VMS internals and data structures [3]. The organization of this book closely follows that of its predecessors. It is divided into nine parts and eight appendices. The parts are
The one change from the VAX/VMS book to this one is the expansion of the material on synchronization from a chapter in the introduction of the old book to a full part in the new. Each part contains an overview, a description of the system services provided by Open VMS AXP, a description of the relevant system data structures, and finally, a description of the control flow.
VAX/VMS internals and data structures has been used in VMS internals classes for a number of years, and that use reflects the purpose of both books: to provide detailed information about the internals of the VMS operating system. The overview sections of the new book could also be used as supplementary material for an operating systems class. This book’s only failure in achieving the first purpose is obsolescence. It documents version 1.5 of Open VMS AXP, but newer versions of Open VMS AXP have already been released. Given this problem, I was surprised that Digital Press chose to release this book in hardback, increasing its cost and the chance that it will be out of date much sooner than it will wear out. For the second purpose, I found that the overview sections on synchronization and memory management had good discussions of the general problems an operating system needs to solve, before delving into the specifics of how these problems are solved in Open VMS AXP. Using the entire book for such a class would be overkill. The book goes into a level of detail that only those who will be working with Open VMS AXP on a regular basis need. That level of detail is both its greatest strength and its biggest weakness. It is a strength because, other than reading the code itself, there is no better way to learn how the system works. It is a weakness because details change faster than books can be updated, and because it is impossible to absorb all of the detail in one reading. This book requires multiple readings, one to get the big picture, and subsequent perusals to review selected chapters as the need arises.
I offer a qualified recommendation. If you deal with the internals of Open VMS AXP, you will want to have access to a copy of this book. But then, you probably already do.
