摘要 这段时间在搞一个微型的Linux,将它作为一个项目的平台，这个过程中，看了研究了一下Linux的启动过程，同时把启动配置文件看了一下，作了一下注释，同时和大家共享一下:)。我使用的Linux平台是Red Hat Linux 7.3 # # inittab This file describes how the INIT process should set up # the system in a certain run-level. # # Author: Miquel van Smoorenburg, # Modified for RHS Linux by Marc Ewing and Donnie Barnes # # Default runlevel. The runlevels used by RHS are: # 0 - halt (Do NOT set initdefault to this) # 1 - Single user mode # 2 - Multiuser, without NFS (The same as 3, if you do not have networking) # 3 - Full multiuser mode # 4 - unused # 5 - X11 # 6 - reboot (Do NOT set initdefault to this) id:3:initdefault: ##这是init进程启动以后读取的第一条内容,用来确定运行级别. ##这条内容读入以后,runlevel这个工具就可以正常显示运行级别了 ##在rc这个脚本文件中将用到runlevel这个工具 # System initialization. si::sysinit:/etc/rc.d/rc.sysin l0:0:wait:/etc/rc.d/rc 0 l1:1:wait:/etc/rc.d/rc 1 l2:2:wait:/etc/rc.d/rc 2 l3:3:wait:/etc/rc.d/rc 3 l4:4:wait:/etc/rc.d/rc 4 l5:5:wait:/etc/rc.d/rc 5 l6:6:wait:/etc/rc.d/rc 6 ##第三个域中的wait表示init进程在启动的时候运行一次后边的内容 ##而且，init进程会等待这个运行的部分正常返回以后才往下运行其它内容。 # Things to run in every runlevel. ud::once:/sbin/update ##这个update使用来自动让你缓存中的数据写回磁盘。 # Trap CTRL-ALT-DELETE ca::ctrlaltdel:/sbin/shutdown -t3 -r now ##定义当用户按下Ctrl+Alt+Delete这三个组合键后init进程做的动作。 # When our UPS tells us power has failed, assume we have a few minutes # of power left. Schedule a shutdown for 2 minutes from now. # This does, of course, assume you have powerd installed and your # UPS connected and working correctly. pf::powerfail:/sbin/shutdown -f -h +2 "Power Failure; System Shutting Down" # If power was restored before the shutdown kicked in, cancel it. pr:12345:powerokwait:/sbin/shutdown -c "Power Restored; Shutdown Cancelled" # Run gettys in standard runlevels 1:2345:respawn:/sbin/mingetty tty1 2:2345:respawn:/sbin/mingetty tty2 3:2345:respawn:/sbin/mingetty tty3 4:2345:respawn:/sbin/mingetty tty4 5:2345:respawn:/sbin/mingetty tty5 6:2345:respawn:/sbin/mingetty tty6 ##第三个域中间的respawn意思是让init进程一直监视后面的进程， ##如果后面的进程结束了，马上重新启动 # Run xdm in runlevel 5 # xdm is now a separate service x:5:respawn:/etc/X11/prefdm -nodaemon
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