Run levels in Sun Solaris

Know the Run levels on Sun Solaris Operating System

The following lists the 6 Run Levels in Sun Solaris. These are often different mostly from the linux run levels

0 - Open Boot prompt (OBP) also called OK prompt. The system is taken down to PROM monitor or Security monitor state. It is safe to power off the hardware.

1,s,S - Single-User or Administrative mode where user logins are disabled. Also minimal Kernel functions and minimal required file systems are mounted (/ and /usr).

2 - Multi-User mode without Networking (No NFS)

3 - Multi-User mode with Networking (Default)

4 - Not in use

5 - Shut-down and power OFF. Power OFF supported on Sun 4m & Sun 4u architecture. More like a boot -a where the system is taken down to run level 0 and then an interactive boot.

6 - Reboot. takes the system down to run level 0 and then back to the default run level (3)