The Windows kernel scans boot parameters in search of the safe-mode switches early during the boot and sets the internal variable InitSafeBootMode to a value that reflects the switches the kernel finds. The kernel writes the InitSafeBootMode value to the registry value HKLM\SYSTEM\CurrentControlSet\SafeBoot\Option\Option Value so that user-mode components, such as the SCM, can determine what boot mode the system is in.