This is the first termination message a virtual device receives for the system virtual machine. The virtual device can begin preparing for termination of the virtual machine. The Simulate_Int and Exec_Int services are available. The system virtual machine is always the last virtual machine to be terminated.
System_Exit
This is the first message a virtual device receives when the system is terminating. The VMM sends it after sending the Sys_VM_Terminate message. Interrupts are enabled, but the Simulate_Int and Exec_Int services are not available. If this message was sent as a result of a fatal error, the virtual device can modify the system virtual machine memory to restore the system state and allow Windows to terminate without hanging.
