Debian's init scripts (the scripts that runs at ["boot"] time ) are found in the directory /etc/init.d/
Init is the first program to run after your system is booted, and continues to run as process number 1 until your system halts. Init's job is to start other programs that are essential to the operation of your system. All processes are descended from init. For more information, see the manual page init(8).
[http://node1.yo-linux.com/cgi-bin/man2html?cgi_command=init Init man page].
[http://linuxreviews.net/man/init/ Init(8) man page].
- update-rc.d, the equivalent to chkconfig