On system bootup, the init process runs the /etc/rc.d/rc.sysinit script to setup the system, such as setting the clock, system font, keyboard map and checking the file systems. rc.sysinit also runs the /etc/rc.d/rc.local script and then runs all the programs in the /etc/rc.d/rc.startup directory, all with the command line parameter start.
For ttylinux systems installed by the /sbin/ttylinux-flash script, the system startup script /etc/rc.d/rc.sysinit attempts to find and mount the drive that is booted from and then run a script on that drive. Remember: this ttylinux system is a RAM disk system, changes made to files are not retained for the next boot because the file system is in RAM. This feature of mounting the booted drive and running a startup script provides the user with a persistent boot-time startup configuration that is retained from one boot to the next. This user-maintainable startup script on the boot drive is in the config/ttylinux directory; a default version of this script is put onto the drive when the /sbin/ttylinux-flash script is run. This script is a very convenient place to configure your particular network interface for ttylinux startup.
On system shutdown, the script /etc/rc.d/rc.sysdone runs. This script runs all the programs in the /etc/rc.d/rc.shutdown directory and then runs the /etc/rc.d/rc.local script, all with the command line parameter stop.
All the programs in /etc/rc.d/rc.startup and /etc/rc.d/rc.shutdown are symbolic links that reference actual shell scripts or binary programs; they are run in the ASCII order of their symbolic link file names. These symbolic links are named with leading numbers to help control their ordering e.g., 10.network is the symbolic link the the network startup program. The actual programs are in /etc/rc.d/init.d. Removing a symbolic link disables the program from starting up. These programs typically are shell scripts; they are commonly called initscripts.
Initscripts can be interactively invoked. The following command runs the network script /etc/rc.d/init.d/syslog with the command line option stop.
service syslog stop
All scripts use the command line options start, stop, reload, restart and status. They print a list of supported options if they are called with no option present.
The initscripts define the basic ttylinux bootup system configuration. The initscripts are configurable to an extent; thus the bootup configuration is configurable to an extent. The bootup system configuration is specified in ASCII text files in the /etc/sysconfig directory; this directory is intended to have only files that are read by the various initscripts. All files read by initscripts for configuration options should reside in /etc/sysconfig.
There are two files in /etc that describe your ttylinux build-time configurations. /etc/ttylinux-host is a text file that describes something about the host architecture that built your ttylinux distribution. /etc/ttylinux-target is a text file that describes some things about the architecture of your running ttylinux distribution.