Microsoft Windows NT Workstation 4.0 is one of the most powerful 32-bit operating systems available for business computing today. It offers the ease of use of Windows 95 along with higher performance, greater reliability, and better security. One of the most remarkable aspects of Windows NT's architecture is that portions of the operating system--the subsystems--run in user-mode processes alongside application processes. The subsystems provide the environments in which applications run. The Win32 subsystem provides the application program interface (API) services that Win32 applications call to do useful things such as create windows and open files. Applications and subsystems en