To give the system administrator a convenient way to shut down or reboot the system and to control system services and resources, eight system run levels (also referred to as init states) are defined and assigned specific functionality. Table 4.5 describes the eight run levels.
|Run Level||init State||Functionality|
|0||Power Down||The system is being shut down. All users are forced off the system. All operating system services are stopped in an orderly manner. When this process is complete, the system is at firmware mode. For SPARC platforms, firmware mode is the ok OpenBoot prompt. It is safe to turn off power to the system and peripherals.|
|s or S||Single User||The system is prepared for maintenance. Any ...|