Windows NT Executive

The Executive, which includes the Kernel and HAL, provides a set of common services that all environment subsystems can use. Each group of services is managed by one of these separate components of the Executive:

• Object Manager
• Virtual Memory Manager
• Process Manager
• Local Procedure Call Facility
• I/O Manager
• Security Reference Monitor, which along with the Logon and Security protected subsystems, makes up the Windows NT security model

Figure 1.2 Windows NT Executive and its Components

A thin top layer of the Executive is called the System Services. The System Services shown in Figure 1.2 are the interface between user-mode environment subsystems and kernel mode. The following sections describe the role of each Executive component.