From Gentoo Linux Wiki

[edit] The initial bootwait process

Following completion of the sysinit system initialization process, the init process triggers the bootwait processes. The inittab configuration file contains the following entry:

rc::bootwait:/sbin/rc boot

This line tells the init process to run to the rc script again, but this time using the boot command line parameter. The init process sets the environmental variables as sysinit before, and runs the !/sbin/rc script again. The script takes the following actions:

Configure the rcsigtrap signal trap, as before

Set the umask to 022, as before

Obtain definitions and functions from the functions.sh include file, as before

Disable the RC_INTERACTIVE flag, if interactive mode is not possible on the terminal type

Define try, check_statedir, noblock_read, user_want_interactive, do_interactive, get_critical_services, and check_critical_services functions.

Set argv1 to the "boot" (passed as a parameter from inittab by the init daemon.)

Configure the initial system path

Run the setup_defaultlevels function to determine if a default runlevel has been specified

If a non-default runlevel has been specified, write this DEFAULTLEVEL to a configuration file.

Export the BOOT flag as a "yes" value

Reset argv1 to BOOTLEVEL (this may have been provided on the kernel command line)

Ensure criticalservices are in the current runlevel.

Run /lib/rcscripts/sh/rc-services.sh

Set OLDSOFTLEVEL = sysinit, Set SOFTLEVEL = boot

Update the splashscreen

Exit if boot /etc/runlevels/boot directory does not exist

Use dolisting to create mylevels as a list of files in /etc/runlevels/boot

Start any coldplug services that failed due to existing /dev/.rcboot

Run the scripts in /etc/runlevels/boot

Remove /dev/.rcboot

Create a list of script names from the mylevels list

Create a set of symlinks to the init scripts in $svcdir (/var/lib/init.d)

Stop all services in get_stop_services

Start all services in get_start_services

Restart devfsd if it is not running

Uninitialize CONSOLETYPE

Update the splash screen

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initdefault The initial default processes