runlevel in Linux and Solaris and AIX

运行级别对于系统使用来说应该是一个很重要的基本概念，原来一直使用Linux，现在又用Solaris和AIX，一下模糊了，他们对runlevel的定义有些许不同，现本人搜集了哈，做个比较。

runlevel	Linux	Solaris
0	halt (Do NOT set initdefault to /etc/inittal "initlevel" entry)	halt
1	Single user mode	Single user mode
2	Multiuser, without NFS (The same as 3, if you do not have networking)	multiuser, unshare net
3	Full multiuser mode	multiuser, deafult
4	unused	unused
5	X11	halt, power off
6	reboot (Do NOT set initdefault to this)	reboot to level 3
S	None	equal “init 1”, “boot -s”

AIX:

"AIX does not follow the System V R4 (SVR4) run level specification, with run levels from 0 to 9 available, as well as from a to c. 0 and 1 are reserved, 2 is the default normal multiuser mode and run levels from 3 to 9 are free to be defined by the administrator. Run levels from a to c allow the execution of processes in that run level without killing processes started in another."

本来想把上个表格做得更全些的，结果在google上一搜，晕！人家http://en.wikipedia.org/wiki/Runlevel做得之巴适！我晕！真是众人拾柴火焰高啊！大家还是有空多去看看wikipedia吧！