Booting

This page contains information about the similarities and differences between different versions of Unix.

Boot Files and Directories

AIX 4.X HP-UX 11.X IRIX 6.X Linux Solaris 2.X
Location of boot scripts /etc/rc* /sbin/init.d /etc/init.d /etc/rc.d/init.d /etc/init.d
Other directories or files containing system defaults, etc. /etc/rc.config.d /etc/config /etc/sysconfig /etc/default
/etc/system

Run Levels

Different systems assign different meanings to run levels, and not all systems implement all possible levels:

Run level AIX 4.X HP-UX 11.X IRIX 6.X Linux Solaris 2.X
S * single-user single-user single-user single-user single-user
0 halt halt halt halt
1 * single-user single-user single-user single-user
2 full multi-user mode
[default] 		same as 3, minus NFS server facility full multi-user mode
[default] 		same as 3, minus NFS server facility same as 3, minus NFS server facility
3 full multi-user mode
[default] 		full multi-user mode
[default] 		full multi-user mode
[default]
4 same as 3, plus HP VUE
5 X Windows under xdm halt & turn power off
6 reboot reboot reboot

* When a system has both run levels S and 1, there may be important differences between them (e.g., what file systems are mounted, whether logins are allowed, etc.).