Red Hat9.0可以使用lilo或grub等引导程序开始引导Linux系统,当引导程序成功完成引导任务后,Linux从它们手中接管了CPU的控制权,然后CPU就开始执行Linux的核心映象代码,开始了Linux启动过程。这里使用了几个汇编程序来引导Linux,这一步泛及到Linux源代码树中的“arch/i386/boot”下的这几个文件:bootsect.S、setup.S、video.S等。
# # 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 havenetworking) # 3 - Full multiuser mode # 4 - unused # 5 - X11 # 6 - reboot (Do NOT set initdefault to this) # ###表示当前缺省运行级别为5(initdefault); id:5:initdefault:
###启动时自动执行/etc/rc.d/rc.sysinit脚本(sysinit) # System initialization. si::sysinit:/etc/rc.d/rc.sysinit
###在启动过程中允许按CTRL-ALT-DELETE重启系统 # Trap CTRL-ALT-DELETE ca::ctrlaltdel:/sbin/shutdown -t3 -r now
# 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"
###在2、3、4、5级别上以ttyX为参数执行/sbin/mingetty程序,打开ttyX终端用于用户登录, ###如果进程退出则再次运行mingetty程序(respawn) # 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
###在5级别上运行xdm程序,提供xdm图形方式登录界面,并在退出时重新执行(respawn) # Run xdm in runlevel 5 x:5:respawn:/etc/X11/prefdm -nodaemon