Because this book describes the internal architecture and operation of Windows 2000, much of the information is subject to change between releases (although external interfaces, such as the Win32 API, are not subject to incompatible changes). For example, we refer to internal Windows 2000 system routines, data structures, and kernel variables as well as to algorithms and values used internally to make resource-sizing and performance-related decisions. These details, by definition, can change between releases.
By "subject to change," we don't necessarily mean that details described in this book will change between releases—but you can't count on them not changing. Any software that uses these undocumented interfaces might not work on future releases of Windows 2000. Even worse, software that runs in kernel mode (such as device drivers) that uses these undocumented interfaces might result in a system crash when upgrading to a newer release of Windows 2000.